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BASIC CHEMISTRY

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BASIC CHEMISTRY

Fourth Edition

KAREN C. TIMBERLAKEWILLIAM TIMBERLAKE

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Copyright © 2014, 2011, 2008, 2005 Pearson Education, Inc. All rights reserved. Manufactured in the United States of America. This publication is protected by Copyright, and permission should be obtained from the publisher prior to any prohibited reproduction, storage in a retrieval system, or transmission in any form or by any means: electronic, mechanical, photocopying, recording, or likewise. To obtain permission1s2 to use material from this work, please submit a written request to Pearson Education, Inc., Permissions Department, 1 Lake Street, Department 1G, Upper Saddle River, NJ 07458.

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Library of Congress Cataloging-in-Publication Data

Timberlake, Karen C. Basic chemistry.—Fourth edition/Karen Timberlake, Los Angeles Valley College, William Timberlake, Los Angeles Harbor College.

pages cm. ISBN-13: 978-0-321-80928-5 ISBN-10: 0-321-80928-9 1. Chemistry—Textbooks. I. Timberlake, William E. II. Title. QD31.3.T54 2014 540—dc23 2012031269

1 2 3 4 5 6 7 8 9 10—CRK—16 15 14 13 12 11

ISBN-10: 0-321-80928-9ISBN-13: 978-0-321-80928-5www.pearsonhighered.com

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1 Chemistry in Our Lives 1

2 Measurements 24

3 Matter and Energy 69

4 Atoms and Elements 104

5 Electronic Structure and Periodic Trends 133

6 Ionic and Molecular Compounds 168

7 Chemical Quantities 207

8 Chemical Reactions 239

9 Chemical Quantities in Reactions 279

10 Properties of Solids and Liquids 306

11 Gases 351

12 Solutions 392

13 Reaction Rates and Chemical Equilibrium 437

14 Acids and Bases 473

15 Oxidation and Reduction 521

16 Nuclear Chemistry 559

17 Organic Chemistry 594

18 Biochemistry 637

Brief Contents

v

vi

1Chemistry in Our Lives 1

1.1 Chemistry and Chemicals 3CHEMISTRY LINK TO HISTORYEarly Chemists: The Alchemists 4

1.2 Scientific Method: Thinking Like a Scientist 6CHEMISTRY LINK TO THE ENVIRONMENTDDT—Good Pesticide, Bad Pesticide 8

1.3 Learning Chemistry: A Study Plan 91.4 Learning Chemistry: Key Math Skills 12

Chapter Review 18Concept Map 19Key Terms 19Key Math Skills 19Understanding the Concepts 20Additional Questions and Problems 21Challenge Questions 22Answers 22

2Measurements 24

2.1 Units of Measurement 252.2 Scientific Notation 282.3 Measured Numbers and Significant Figures 322.4 Significant Figures in Calculations 352.5 Prefixes and Equalities 382.6 Writing Conversion Factors 42

CHEMISTRY LINK TO HEALTH Toxicology and Risk–Benefit Assessment 47

2.7 Problem Solving Using Unit Conversion 482.8 Density 54

CHEMISTRY LINK TO THE ENVIRONMENT Density of Crude Oil 56CHEMISTRY LINK TO HEALTHBone Density 59

Table of Contents

Chapter Review 61Concept Map 62Key Terms 62Key Math Skills 63Core Chemistry Skills 63Understanding the Concepts 64Additional Questions and Problems 65Challenge Questions 66Answers 67

3Matter and Energy 69

3.1 Classification of Matter 70CHEMISTRY LINK TO HEALTHBreathing Mixtures for Scuba 73

3.2 States and Properties of Matter 743.3 Temperature 78

CHEMISTRY LINK TO HEALTHVariation in Body Temperature 82

3.4 Energy 833.5 Specific Heat 85

CHEMISTRY LINK TO THE ENVIRONMENTCarbon Dioxide and Global Warming 89

3.6 Energy and Nutrition 91CHEMISTRY LINK TO HEALTHLosing and Gaining Weight 94

Chapter Review 95Concept Map 96Key Terms 96Core Chemistry Skills 97Understanding the Concepts 98Additional Questions and Problems 99Challenge Questions 100Answers 100

Combining Ideas from Chapters 1 to 3 102

vi

TABLE OF CONTENTS vii

4Atoms and Elements 104

4.1 Elements and Symbols 105CHEMISTRY LINK TO INDUSTRYMany Forms of Carbon 106CHEMISTRY LINK TO HEALTH Mercury 108

4.2 The Periodic Table 108CHEMISTRY LINK TO HEALTHElements Essential to Health 113

4.3 The Atom 1154.4 Atomic Number and Mass Number 1184.5 Isotopes and Atomic Mass 122


5Electronic Structure and Periodic Trends 133

5.1 Electromagnetic Radiation 134CHEMISTRY LINK TO HEALTH Biological Reactions to UV Light 136

5.2 Atomic Spectra and Energy Levels 138CHEMISTRY LINK TO THE ENVIRONMENTEnergy-Saving Fluorescent Bulbs 140

5.3 Sublevels and Orbitals 1415.4 Orbital Diagrams and Electron

Configurations 1455.5 Electron Configurations and the

Periodic Table 1505.6 Trends in Periodic Properties 154

Chapter Review 161Concept Map 162

Key Terms 163Core Chemistry Skills 163Understanding the Concepts 164Additional Questions and Problems 164Challenge Questions 165Answers 166

6Ionic and Molecular Compounds 168

6.1 Ions: Transfer of Electrons 169CHEMISTRY LINK TO INDUSTRYSome Uses for Noble Gases 170CHEMISTRY LINK TO HEALTH Some Important Ions in the Body 174

6.2 Writing Formulas for Ionic Compounds 1756.3 Naming Ionic Compounds 1786.4 Polyatomic Ions 1826.5 Molecular Compounds: Sharing Electrons 1876.6 Organic Compounds: Extended Topic 1936.7 Names and Formulas of Alkanes: Extended

Topic 195CHEMISTRY LINK TO INDUSTRYCrude Oil 198


7Chemical Quantities 207

7.1 The Mole 2087.2 Molar Mass 2137.3 Calculations Using Molar Mass 2157.4 Mass Percent Composition and Empirical

Formulas 219CHEMISTRY LINK TO THE ENVIRONMENTFertilizers 221

viii TABLE OF CONTENTS

9Chemical Quantities in Reactions 279

9.1 Mole Relationships in Chemical Equations 2809.2 Mass Calculations for Reactions 2859.3 Limiting Reactants 2889.4 Percent Yield 2929.5 Energy in Chemical Reactions 294

CHEMISTRY LINK TO HEALTH Cold Packs and Hot Packs 297


10Properties of Solids and Liquids 306

10.1 Electron-Dot Formulas 30710.2 Shapes of Molecules and Ions 1VSEPR Theory2 31410.3 Electronegativity and Polarity 31810.4 Attractive Forces in Compounds 324

CHEMISTRY LINK TO HEALTH Attractive Forces in Biological Compounds 327

10.5 Changes of State 328CHEMISTRY LINK TO HEALTH Steam Burns 336



7.5 Molecular Formulas 226



8Chemical Reactions 239

8.1 Equations for Chemical Reactions 2408.2 Balancing a Chemical Equation 2448.3 Types of Reactions 247

CHEMISTRY LINK TO HEALTH Smog and Health Concerns 249CHEMISTRY LINK TO HEALTH Incomplete Combustion: Toxicity of Carbon Monoxide 252

8.4 Functional Groups and Reactions of Organic Compounds: Extended Topic 253CHEMISTRY LINK TO THE ENVIRONMENTPheromones in Insect Communication 255CHEMISTRY LINK TO HEALTH Polycyclic Aromatic Hydrocarbons 1PAHs2 256CHEMISTRY LINK TO HEALTH Hand Sanitizers and Ethanol 257CHEMISTRY LINK TO HEALTHSalicylic Acid from the Willow Tree 259CHEMISTRY LINK TO HEALTHAmines in Health and Medicine 260

8.5 Biochemical Compounds: Extended Topic 263CHEMISTRY LINK TO HEALTH Omega-3 Fatty Acids in Fish Oils 264CHEMISTRY LINK TO INDUSTRYHydrogenation of Unsaturated Fats 266

Chapter Review 270Concept Map 271Key Terms 271Core Chemistry Skills 272Summary of Reactions 273Understanding the Concepts 273Additional Questions and Problems 275Challenge Questions 276Answers 277

TABLE OF CONTENTS ix

12.4 Concentration of Solutions 40512.5 Dilution and Chemical Reactions in Solution 41112.6 Properties of Solutions 418

CHEMISTRY LINK TO HEALTH Dialysis by the Kidneys and the Artificial Kidney 426


13Reaction Rates and Chemical Equilibrium 437

13.1 Rates of Reactions 439CHEMISTRY LINK TO THE ENVIRONMENT Catalytic Converters 442

13.2 Chemical Equilibrium 44313.3 Equilibrium Constants 44613.4 Using Equilibrium Constants 45113.5 Changing Equilibrium Conditions: Le Châtelier’s

Principle 454CHEMISTRY LINK TO HEALTH Oxygen–Hemoglobin Equilibrium and Hypoxia 457CHEMISTRY LINK TO HEALTH Homeostasis: Regulation of Body Temperature 460

13.6 Equilibrium in Saturated Solutions 461


11Gases 351

11.1 Properties of Gases 352CHEMISTRY LINK TO HEALTH Measuring Blood Pressure 355

11.2 Gas Pressure 35611.3 Pressure and Volume 1Boyle’s Law2 358

CHEMISTRY LINK TO HEALTH Pressure–Volume Relationship in Breathing 361

11.4 Temperature and Volume 1Charles’s Law2 362CHEMISTRY LINK TO THE ENVIRONMENTGreenhouse Gases 364

11.5 Temperature and Pressure 1Gay-Lussac’s Law2 366

11.6 The Combined Gas Law 36911.7 Volume and Moles 1Avogadro’s Law2 37111.8 The Ideal Gas Law 37511.9 Gas Laws and Chemical Reactions 37811.10 Partial Pressures 1Dalton’s Law2 380

CHEMISTRY LINK TO HEALTH Blood Gases 383CHEMISTRY LINK TO HEALTH Hyperbaric Chambers 384


12Solutions 392

12.1 Solutions 393CHEMISTRY LINK TO HEALTH Water in the Body 395

12.2 Electrolytes and Nonelectrolytes 39812.3 Solubility 400

CHEMISTRY LINK TO HEALTH Gout and Kidney Stones: A Problem of Saturation in Body Fluids 403

x TABLE OF CONTENTS

CHEMISTRY LINK TO THE ENVIRONMENTFuel Cells: Clean Energy for the Future 542

15.5 Oxidation–Reduction Reactions That Require Electrical Energy 543

15.6 Oxidation of Alcohols: Extended Topic 545CHEMISTRY LINK TO HEALTH Oxidation of Ethanol in the Body 547

Chapter Review 548Summary of Reactions 549Concept Map 550Key Terms 550Core Chemistry Skills 550Understanding the Concepts 552Additional Questions and Problems 553Challenge Questions 554Answers 555

16Nuclear Chemistry 559

16.1 Natural Radioactivity 56016.2 Nuclear Reactions 564

CHEMISTRY LINK TO THE ENVIRONMENTRadon in Our Homes 566

16.3 Radiation Measurement 571CHEMISTRY LINK TO THE ENVIRONMENTRadiation and Food 573

16.4 Half-Life of a Radioisotope 575CHEMISTRY LINK TO THE ENVIRONMENTDating Ancient Objects 577

16.5 Medical Applications Using Radioactivity 579CHEMISTRY LINK TO HEALTH Brachytherapy 581

16.6 Nuclear Fission and Fusion 582CHEMISTRY LINK TO THE ENVIRONMENTNuclear Power Plants 585


Combining Ideas from Chapters 15 and 16 592

14Acids and Bases 473

14.1 Acids and Bases 47514.2 Brønsted–Lowry Acids

and Bases 47814.3 Strengths of Acids and Bases 48114.4 Dissociation Constants for Acids and Bases 48614.5 Ionization of Water 48814.6 The pH Scale 491

CHEMISTRY LINK TO HEALTH Stomach Acid, HCl 498

14.7 Reactions of Acids and Bases 499CHEMISTRY LINK TO THE ENVIRONMENTAcid Rain 500CHEMISTRY LINK TO HEALTH Antacids 502

14.8 Acid–Base Titration 50314.9 Buffers 505

CHEMISTRY LINK TO HEALTH Buffers in the Blood 508

Chapter Review 510Concept Map 512Key Terms 512Key Math Skills 513Core Chemistry Skills 513Understanding the Concepts 514Additional Questions and Problems 515Challenge Questions 515Answers 517


15Oxidation and Reduction 521

15.1 Oxidation–Reduction Reactions 52315.2 Oxidation Numbers 52515.3 Balancing Oxidation–Reduction Equations Using

Half-Reactions 52915.4 Electrical Energy from Oxidation–Reduction

Reactions 534CHEMISTRY LINK TO THE ENVIRONMENTCorrosion: Oxidation of Metals 540

TABLE OF CONTENTS xi

18Biochemistry 637

18.1 Carbohydrates 638CHEMISTRY LINK TO HEALTH Hyperglycemia and Hypoglycemia 640

18.2 Disaccharides and Polysaccharides 644CHEMISTRY LINK TO HEALTH How Sweet Is My Sweetener? 646

18.3 Lipids 651CHEMISTRY LINK TO HEALTH Olestra: A Fat Substitute 657CHEMISTRY LINK TO HEALTH Trans Fatty Acids and Hydrogenation 658

18.4 Proteins 660CHEMISTRY LINK TO HEALTH Essential Amino Acids 663

18.5 Protein Structure 66518.6 Proteins as Enzymes 66918.7 Nucleic Acids 67118.8 Protein Synthesis 677

Chapter Review 682Concept Map 683Key Terms 684Understanding the Concepts 685Additional Questions and Problems 686Challenge Questions 687Answers 688

Combining Ideas from Chapters 17 and 18 691

Credits C-1

Glossary/Index I-1

17Organic Chemistry 594

17.1 Alkanes and Naming Substituents 595

17.2 Alkenes, Alkynes, and Polymers 60117.3 Aromatic Compounds 605

CHEMISTRY LINK TO THE ENVIRONMENTSome Common Aromatic Compounds 606

17.4 Alcohols, Phenols, and Ethers 608CHEMISTRY LINK TO HEALTH Some Important Alcohols and Phenols 609

17.5 Aldehydes and Ketones 611CHEMISTRY LINK TO THE ENVIRONMENTVanilla 613

17.6 Carboxylic Acids and Esters 615CHEMISTRY LINK TO HEALTH Carboxylic Acids in Metabolism 617

17.7 Amines and Amides 622CHEMISTRY LINK TO THE ENVIRONMENTAlkaloids: Amines in Plants 624

Chapter Review 628Concept Map 630Summary of Naming 630Summary of Reactions 631Key Terms 631Understanding the Concepts 632Additional Questions and Problems 632Challenge Questions 634Answers 634

xii

vv

Classifying Types of Chemical Reactions 247Balancing Combustion Reactions 251Identifying Functional Groups 254Using Mole–Mole Factors 282Converting Grams to Grams 285Calculating Quantity of Product from a Limiting

Reactant 289Calculating Percent Yield 292Using the Heat of Reaction 296Drawing Electron-Dot Formulas 308Drawing Resonance Structures 311Predicting Shape 314Using Electronegativity 318Identifying Polarity of Molecules 322Identifying Attractive Forces 324Calculating Heat for Change of State 330Using the Gas Laws 359Using the Ideal Gas Law 375Calculating Mass or Volume of a Gas in a Chemical

Reaction 378Calculating Partial Pressure 380Using Solubility Rules 402Calculating Concentration 406Using Concentration as a Conversion Factor 409Calculating the Quantity of a Reactant or Product for a

Chemical Reaction in Solution 414Calculating Temperature Change 421Writing the Equilibrium Constant Expression 447Calculating an Equilibrium Constant 449Calculating Equilibrium Concentrations 453Using Le Châtelier’s Principle 455Writing the Solubility Product Expression 461Calculating a Solubility Product Constant 462Calculating the Molar Solubility 463Identifying Conjugate Acid–Base Pairs 479Calculating 3H3O+4 and 3OH- 4 in Solutions 490Writing Equations for Reactions of Acids and Bases 500Calculating Molarity or Volume of an Acid or Base in a

Titration 503Calculating the pH of a Buffer 506Identifying Oxidized and Reduced Substances 523Assigning Oxidation Numbers 525Using Oxidation Numbers 527Identifying Oxidizing and Reducing Agents 528Using Half-Reactions to Balance Redox Equations 529Identifying Spontaneous Reactions 534Writing Nuclear Equations 564Using Half-Lives 575

Key Math SkillsIdentifying Place Values 12Using Positive and Negative Numbers in Calculations 13Calculating a Percentage 14Solving Equations 14Interpreting a Line Graph 16Using Scientific Notation 29Calculating pH from 3H3O+ 4 493Calculating 3H3O+ 4 from pH 497

Core Chemistry SkillsCounting Significant Figures 33Rounding Off 35Using Significant Figures in Calculations 36Using Prefixes 39Writing Conversion Factors from Equalities 42Using Conversion Factors 48Using Density as a Conversion Factor 58Classifying Matter 70Identifying Physical and Chemical Changes 75Converting between Temperature Scales 79Using Energy Units 84Calculating Specific Heat 85Using the Heat Equation 87Counting Protons and Neutrons 119Writing Atomic Symbols for Isotopes 122Writing Electron Configurations 146Using the Periodic Table to Write Electron

Configurations 150Identifying Trends in Periodic Properties 154Drawing Electron-Dot Symbols 156Writing Positive and Negative Ions 170Writing Ionic Formulas 177Naming Ionic Compounds 178Writing the Names and Formulas for Molecular

Compounds 189Naming and Drawing Alkanes 196Converting Particles to Moles 208Calculating Molar Mass 213Using Molar Mass as a Conversion Factor 215Calculating Mass Percent Composition 219Calculating an Empirical Formula 221Calculating a Molecular Formula 227Balancing a Chemical Equation 244

Applications and Activities

xii

APPLICATIONS AND ACTIVITIES xiii

Determination of Polarity of a Molecule 323Calculations Using Heat of Fusion 330Calculations Using Heat of Vaporization 333Using the Gas Laws 359Using Molar Volume 373Using the Ideal Gas Law 376Calculating the Molar Mass of a Gas 377Reactions Involving the Ideal Gas Law 379Calculating Partial Pressure 381Gases Collected over Water 382Writing an Equation for the Formation of an Insoluble

Salt 404Calculating Solution Concentration 406Using Concentration to Calculate Mass or Volume 409Calculating Dilution Quantities 413Calculations Involving Solutions in Chemical

Reactions 414Calculating Molality 420Using Molality 422Writing the Equilibrium Constant Expression 448Calculating the Kc Value 450Using the Equilibrium Constant 453Calculating Ksp 462Calculating Molar Solubility from Ksp 463Writing Conjugate Acid–Base Pairs 480Calculating 3H3O+ 4 and 3OH- 4 in Aqueous

Solutions 490Calculating pH of an Aqueous Solution 495Calculating 3H3O+ 4 from pH 497Balancing an Equation for Neutralization 501Calculations for an Acid–Base Titration 504Calculating pH of a Buffer 507Using Oxidation Numbers 527Balancing Redox Equations Using Half-Reactions 530Completing a Nuclear Equation 565Using Half-Lives 576Naming Alkanes 598Drawing Alkane Formulas 599Naming Alkenes and Alkynes 601Naming Aromatic Compounds 607Naming Alcohols 609Naming Aldehydes 612Naming Ketones 614Naming Carboxylic Acids 616Naming Esters 621Drawing Haworth Structures 641

Guide to Problem Solving

Writing a Number in Scientific Notation 31Using Conversion Factors 50Calculating Density 56Using Density 58Calculating Temperature 80Calculating Specific Heat 87Calculations Using Specific Heat 87Calculating the Energy from a Food 93Using the Wave Equation 137Drawing Orbital Diagrams 148Writing Electron Configurations Using Sublevel

Blocks 152Naming Ionic Compounds with Metals That Form a

Single Ion 178Naming Ionic Compounds with Variable Charge

Metals 180Writing Formulas from the Name of an Ionic

Compound 181Writing Formulas with Polyatomic Ions 184Naming Ionic Compounds with Polyatomic Ions 185Naming Molecular Compounds 190Writing Formulas for Molecular Compounds 191Calculating the Atoms or Molecules of a Substance 210Calculating Moles 212Calculating Molar Mass 214Calculating the Moles 1or Grams2 of a Substance from

Grams 1or Moles2 216Calculating the Particles of a Substance from Grams 218Calculating Mass Percent Composition 220Calculating an Empirical Formula 222Calculating a Molecular Formula from an Empirical

Formula 228Balancing a Chemical Equation 244Calculating the Quantities of Reactants and Products in a

Chemical Reaction 283Calculating the Moles of Product from a Limiting

Reactant 289Calculating the Grams of Product from a Limiting

Reactant 290Calculations for Percent Yield 293Calculations Using the Heat of Reaction 1!H2 297Drawing Electron-Dot Formulas 308Predicting Molecular Shape 1VSEPR Theory2 317

xiv

Welcome to the fourth edition of Basic Chemistry. This text was written and designed to help you prepare for science-related professions, such as engineering, nursing, medicine, environ-mental or agricultural science, or for careers such as laboratory technology. This text assumes no prior knowledge of chemistry. The main objective in writing this text is to make the study of chemistry an engaging and positive experience for you by relat-ing the structure and behavior of matter to real life. This new edition introduces more problem-solving strategies, including math remediation, new concept checks, more problem-solving guides, new Analyze the Problem features, conceptual and chal-lenge problems, and new sets of combined problems.

It is our goal to help you become a critical thinker by understanding scientific concepts that will form a basis for making important decisions about issues concerning health and the environment. Thus, we have utilized materials that

• help you to learn and enjoy chemistry• develop problem-solving skills that lead to success in

your chemistry course• promote learning and success in your chosen career

New to This Fourth EditionNew and updated features have been added throughout this fourth edition, including the following:

• Chapter Openers provide timely examples and engag-ing, topical issues of the chemistry that is part of contem-porary professions.

• Integrated math remediation includes new Key Math Skills that review basic math relevant to chemistry throughout the text concluding with a Key Math Skills review at the end of each chapter with examples.

• Core Chemistry Skills icons identify the key chemi-cal principles in each chapter that are required for suc-cessfully learning chemistry. A Core Chemistry Skills review at the end of each chapter summarizes and gives examples.

• Chapter Readiness at the beginning of each chapter lists the Key Math Skills and Core Chemistry Skills from the previous chapters that provide the foundation for new chemistry principles in the current chapter.

• Analyze the Problem features that are now included in the solutions of the Sample Problems to strengthen critical-thinking skills illustrate the breakdown of a word problem into the components required to solve it.

• UPDATED! Combining Ideas features offer sets of integrated problems that test students’ understanding by integrating topics from two or more previous chapters.

• UPDATED! End-of-Chapter Problems based on reviewer feedback and MasteringChemistry® metadata ensure a range of difficulty levels, while added section references make homework and review more efficient for students.

• UPDATED! Chemistry Link to Health boxes, “Brachy-therapy,” “Polycyclic Aromatic Hydrocarbons 1PAHs2,” and “Breathing Mixtures for Scuba,” have been added.

• UPDATED! Chemistry Link to the Environment boxes, “Energy-Saving Fluorescent Bulbs,” “Vanilla,” and “Pheromones in Insect Communication,” have been added.

• UPDATED! Guides to Problem Solving have been added.• UPDATED! Chapter Reviews now include bulleted

lists and thumbnail art samples related to the content of each section.

Chapter-by-Chapter Organization and Changes to the Fourth EditionIn each textbook we write, we consider it essential to relate every chemical concept to real-life issues of health and envi-ronment. Because a chemistry course may be taught in differ-ent time frames, it may be difficult to cover all the chapters in this text. However, each chapter is a complete package, which allows some chapters to be skipped or the order of presenta-tion to be changed. In this edition, we have incorporated many topics of organic chemistry from Chapter 17 and some of bio-chemistry from Chapter 18 into the early chapters of the text to integrate general chemistry with organic chemistry.

Chapter 1, Chemistry in Our Lives, introduces the concepts of chemicals and chemistry, discusses the scientific method in everyday terms, and guides students in developing a study plan for learning chemistry.

• New Chapter Opener features the work and career of a forensic scientist.

• A new section, “Learning Chemistry: Key Math Skills,” reviews basic math required in chemistry, such as place values, positive and negative numbers, percentages, solv-ing equations, and interpreting a line graph.

Chapter 2, Measurements, looks at measurement and empha-sizes the need to understand numerical relationships of the

Preface

xiv

PREFACE xv

metric system. An explanation of scientific notation and work-ing with a calculator is included in the chapter.

• New Chapter Opener features the work and career of a registered nurse.

• New Guide to Writing a Number in Scientific Notation was added.

• New material was added that illustrates how to count significant figures in equalities and in conversion factors used in a problem setup.

• New photos that were added include the standard kilo-gram, mass of a nickel, and a virus.

• The number of parts in multiple-part questions in MasteringChemistry was reduced when time needed for students to complete them exceeded 15 minutes.

Chapter 3, Matter and Energy, classifies matter and states of matter, describes temperature measurement, and discusses energy and its measurement. Physical and chemical changes and physical and chemical properties are now discussed in more depth. The section on forms of energy has been deleted. The feature Combining Ideas utilizing concepts from Chapters 1, 2, and 3 follows as an interchapter problem set.

• New Chapter Opener features the work and career of a dietitian.

• New Guide to Calculating Temperature was added.• New problems were added to complete matched sets of

problems.• The effect of the high specific heat of water on coastal

cities compared to inland cities was added.• New Guide to Calculating Specific Heat was added.• New Guide to Calculating Energy from a Food was

added.• Problems with high difficulty in MasteringChemistry

were rewritten to identify data and needed answers.

Chapter 4, Atoms and Elements, looks at elements, atoms, subatomic particles, atomic numbers, and mass numbers. Using the naturally occurring isotopes and abundances, atomic mass is calculated.

• New Chapter Opener now features the chemistry utilized by a farmer and farming as a career.

• Number of elements now given as 118.• Table 4.1 was expanded to include the symbols of the

elements listed.• Symbols of the elements Copernicium, Cn 11122 ,

Flerovium, Fl 11142, and Livermorium, Lv 11162 were added to the periodic table of elements.

• “Chemistry Link to Industry: Many Forms of Carbon” was moved into Section 4.1, “Elements and Symbols.”

• Photo upgrades through Chapter 4 improve the visual representations of concepts.

• Updated art for the nuclei of the three naturally occurring magnesium isotopes now shows them as three different shades of blue.

• New analogy for the weighted average of bowling balls now introduces concepts of weighted average for atomic mass of an element.

• Table 4.8 now includes the “most prevalent isotopes.”• Isotopes and percent abundances of thallium and rubid-

ium are now included in atomic mass calculations.• Questions and Problems in MasteringChemistry that had

high difficulty for students were rewritten.

Chapter 5, Electronic Structure and Periodic Trends, uses the electromagnetic spectrum to explain atomic spectra and develop the concept of energy levels and sublevels. Electrons in sublev-els and orbitals are represented using orbital diagrams and elec-tron configurations. Periodic properties of elements, including atomic radius and ionization energy, are related to their valence electrons. Section 5.4 is now titled “Orbital Diagrams and Electron Configurations.” Section 5.6 is now titled “Trends in Periodic Properties.” Small periodic tables have been added to Section 5.6 to illustrate the trends of periodic properties.

• New Chapter Opener features engineers working in the field of materials science.

• Peaks and dips of a wave are now described as crests and troughs.

• The wave equation is now solved for wavelength or for frequency.

• New Guide to Using the Wave Equation was added.• New Guide to Drawing Orbital Diagrams was added.• The discussion on electron energy levels was rewritten,

and an updated illustration of energy levels was added.• New diagrams of the d orbitals have been added to the

representations of s and p orbitals.• A discussion of metallic character has been added to Sec-

tion 5.6, “Trends in Periodic Properties.”• A new summary of the properties for valence electrons,

atomic size, ionization energy, and metallic character from top to bottom of a group and going from left to right across a period was added to Section 5.6, “Trends in Periodic Properties.”

Chapter 6, Ionic and Molecular Compounds, describes how atoms form ionic and covalent bonds. Chemical formulas are written, and ionic compounds—including those with polyatomic ions—and molecular compounds are named. An introduction to the three-dimensional shape of carbon molecules provides a basis for the shape of organic and biochemical compounds. Organic chemistry is introduced with the properties of inorganic and organic compounds and condensed structural formulas of alkanes. Section 6.1 is now titled “Ions: Transfer of Electrons,” 6.2 is titled “Writing Formulas for Ionic Compounds,” 6.3 is

xvi PREFACE

titled “Naming Ionic Compounds,” and 6.5 is titled “Molecular Compounds: Sharing Electrons.”

• New Chapter Opener features the work and career of a pharmacist.

• “Ions: Transfer of Electrons” has been rewritten to emphasize the stability of the electron configuration of a noble gas.

• New art comparing the particles and bonding of ionic compounds and molecular compounds has been added.

• New flowchart for Naming Chemical Compounds in Section 6.5 shows naming patterns for ionic and molecu-lar compounds and includes naming alkanes.

• New Guide to Writing Formulas with Polyatomic Ions was added.

• New Concept Check, “Electron-Dot Formulas,” was added.

• New Concept Checks include the names and formulas of ionic and covalent compounds.

• “Organic Compounds” and “Names and Formulas of Alkanes” are labeled as Extended Topics.

• Representations of methane and ethane have been updated to emphasize the tetrahedral shape.

• The skeletal formulas of alkanes have been added to the types of formulas for drawing alkanes.

Chapter 7, Chemical Quantities, discusses Avogadro’s number, the mole, and molar masses of compounds, which are used in calculations to determine the mass or number of particles in a quantity of a substance. The mass percent composition of a compound is calculated and used to determine its empirical and molecular formula. Combining Ideas from Chapters 4, 5, 6, and 7 follows as an interchapter problem set.

• New Chapter Opener describes the work and career of a veterinarian.

• The periodic table in Section 7.2 now includes symbols of Fl 11142 and Lv 11162.

• New Concept Check 7.4, “Calculating Mass Percent from Experimental Data,” was added.

• New Guide to Calculating Moles was added.• New Guide to Calculating Mass Percent Composition

was added.

Chapter 8, Chemical Reactions, looks at the interaction of atoms and molecules in chemical reactions. Chemical equa-tions are balanced and organized into combination, decomposi-tion, single replacement, double replacement, and combustion reactions. Section 8.4, “Functional Groups and Reactions of Organic Compounds,” and Section 8.5, “Biochemical Com-pounds,” are now Extended Topics, which classify compounds according to their structures to predict their properties and reactions. The Chemistry Link to Health features, “Amines in Health and Medicine” and “Omega-3 Fatty Acids in Fish Oils,”

and the Chemistry Link to Industry feature, “Hydrogenation of Unsaturated Fats,” are included in Chapter 8.

• New Chapter Opener describes the work and career of an exercise physiologist.

• Section 8.3, “Types of Reactions,” now includes combus-tion reactions and balancing equations for combustion reactions.

• Chemistry Links to Health were added, including “Hand Sanitizers and Ethanol,” “Polycyclic Aromatic Hydrocar-bons 1PAHs2” 1moved from Chapter 172, and “Salicylic Acid from the Willow Tree” 1moved from Chapter 142, and a new Chemistry Link to the Environment, “Phero-mones in Insect Communication,” was also added.

• Section 8.5 is now titled “Biochemical Compounds: Extended Topic,” which discusses functional groups in carbohydrates, lipids, and proteins.

Chapter 9, Chemical Quantities in Reactions, describes the mole and mass relationships among the reactants and prod-ucts and provides calculations of limiting reactants and percent yields. A section on “Energy in Chemical Reactions” com-pletes the chapter.

• New Chapter Opener describes the work and career of an environmental scientist.

• Mole and mass relationships among the reactants and products are examined along with calculations of percent yield and limiting reactants.

• A new diagram illustrates the process of changing grams of one substance to the grams of another substance.

• New diagrams illustrate the change in energy level of reactants and products for exothermic reactions and for endothermic reactions.

Chapter 10, Properties of Solids and Liquids, introduces elec-tron-dot formulas for molecules and ions with single and mul-tiple bonds as well as resonance structures. Electronegativity leads to a discussion of the polarity of bonds and molecules. Electron-dot formulas and VSEPR theory illustrate covalent bonding and the three-dimensional shapes of molecules and ions. The attractive forces between particles and their impact on states of matter and changes of state are described. Combin-ing Ideas from Chapters 8, 9, and 10 follows as an interchapter problem set.

• New Chapter Opener describes the work and career of a histologist.

• New illustrations of molecular models provide visual representations of three-dimensional structures.

• New wedge–dash notation for tetrahedral structures and trigonal pyramidal structures was added.

• The heating curve, Figure 10.6, for water has been updated.

PREFACE xvii

• Ethanol, acetic acid, and acetone have been added to heat calculations.

• Heat equation for combining energy calculations is reviewed.

• A new Guide to Determination of Polarity of a Molecule has been added.

• The Guides to Calculations Using Heat of Fusion and Heat of Vaporization were rewritten.

• Table 10.6, Comparison of Bonding and Attractive Forces, has been updated.

• A new diagram of unsymmetrical distribution of elec-trons in nonpolar molecules to give weak dispersion force attractions was added.

• Sublimation was moved to the end of the chapter.

Chapter 11, Gases, describes the properties of a gas and calcu-lates changes in gases using the gas laws and the ideal gas law. The amounts of gases required or produced in chemical reac-tions are calculated.

• New Chapter Opener describes the work and career of a respiratory therapist.

• A table of initial and final gas conditions now includes the factors that remain constant.

• A new Guide to Calculating the Molar Mass of a Gas has been added.

• Several GPS Steps have been rewritten.

Chapter 12, Solutions, describes solutions, saturation and solu-bility, concentrations, and colligative properties. The volumes and molarities of solutions are used in calculations of reactants and products in chemical reactions, as well as dilutions and titra-tions. Section 12.4 is now titled “Concentration of Solutions” and Section 12.5 is now titled “Dilution and Chemical Reactions in Solution.” Section 12.6, “Properties of Solutions,” discusses the properties of solutions and the impact of particle concentra-tion on the boiling point, freezing point, and osmotic pressure.

• New Chapter Opener describes the work and career of a dialysis nurse.

• Sections on “Formation of Solutions” and “Electrolytes” have been rewritten for improved clarity.

• New photos added include rock candy made from a satu-rated sugar solution, vanilla extract and lemon extract, and the Alaska Upis beetle, which produces its own bio-logical antifreeze.

• A new Table 12.7 summarizes percent concentration and molarity and their units.

• A new Guide to Calculating Molality was added.• A new Guide to Using Molality was added.• New material on using molality to calculate freezing

point depression and boiling point elevation was added.• New problems were added to provide matched sets of

problems.

Chapter 13, Reaction Rates and Chemical Equilibrium, looks at the rates of reactions and the equilibrium condition when forward and reverse rates for a reaction become equal. Equilibrium expressions for reactions are written, and equi-librium constants are calculated. Using equilibrium constants, reactions are evaluated to determine whether stress causes the equilibrium to shift in the direction of the reactants or the products. Le Châtelier’s principle is used to evaluate the impact on concentrations when a stress is placed on the equi-librium system. The equilibrium of dissolving and crystalliz-ing in saturated solutions is evaluated using solubility product constants.

• New Chapter Opener describes the work and career of a chemical oceanographer.

• Enzymes in laundry detergents are discussed as examples of catalysts in everyday products.

• Art in Figures 13.8 and 13.9 has been updated.• A new diagram of analogy of water in tanks reaching

equilibrium has been added. • A new Figure 13.11 has been added, illustrating the

effect of concentration changes on equilibrium.• Updated diagrams illustrate the decrease of reactants and

increase of products to reach equilibrium.• Guides to Writing the Equilibrium Constant Expression,

Calculating the Kc Value, Using the Equilibrium Con-stant, Calculating Ksp, and Calculating Molar Solubility from Ksp have been updated and rewritten.

• Art on the effect of adding a common ion of Mg2 + or CO3

2 - to a solution of MgCO3 has been updated.• New photos of slightly soluble salts, including calcium

oxalate, calcium carbonate, and cadmium sulfide, have been added.

Chapter 14, Acids and Bases, discusses acids and bases and their strengths, conjugate acid–base pairs, the dissociation of weak acids and bases and water, pH and pOH, and buffers. Acid–base titration uses the neutralization reactions between acids and bases to calculate quantities of acid in a sample. Sec-tion 14.9, “Acid–Base Properties of Salt Solutions,” has been deleted. Combining Ideas from Chapters 11, 12, 13, and 14 fol-lows as an interchapter problem set.

• New Chapter Opener describes the work and career of a clinical laboratory technician.

• Three-dimensional models of sulfuric acid, bicarbonate, carbonic acid, formate, and formic acid were added.

• Table 14.4, Relative Strengths of Acids and Bases, was moved to Section 14.3, “Strengths of Acids and Bases.”

• A new Guide to Writing Conjugate Acid–Base Pairs has been added.

• New material on diprotic acids has been added.• New art on weak acid hydrofluoric acid was added.

xviii PREFACE

• New material and art on gastric cells and the produc-tion of HCl has been added to Chemistry Link to Health, “Stomach Acid, HCl.”

• New photos of calcium hydroxide and information about its use in the food industry, dentistry, and preparation of corn kernels for hominy were added.

• Guides to Calculating 3H3O+ 4 and 3OH- 4 in Aqueous

Solutions and Calculating pH of an Aqueous Solution have been rewritten.

• A new Guide Calculating 3H3O+ 4 from pH was added.

• A new photo of sodium bicarbonate reacting with acetic acid has been added to chemical reactions of acids and bases.

Chapter 15, Oxidation and Reduction, looks at the character-istics of oxidation and reduction reactions. Oxidation numbers are assigned to the atoms in elements, molecules, and ions to determine the components that lose electrons during oxidation and gain electrons during reduction. The half-reaction method is utilized to balance oxidation–reduction reactions. The pro-duction of electrical energy in voltaic cells and the requirement of electrical energy in electrolytic cells are diagrammed using half-cells. The activity series is used to determine the spontane-ous direction of an oxidation–reduction reaction.

• New Chapter Opener describes the work and career of a dentist.

• A new Guide to Using Oxidation Numbers has been added.

• Oxidation–reduction equations are now balanced using half-reactions in acidic or basic solutions.

• The Guide to Balancing Redox Equations Using Half-Reactions was rewritten.

• Section 15.4, which is titled “Electrical Energy from Oxidation–Reduction Reactions,” now begins with the Activity Series followed by Voltaic Cells.

• The section “Oxidation of Alcohols” is now an Extended Topic at the end of the chapter and includes the oxidation of alcohol in the body.

Chapter 16, Nuclear Chemistry, looks at the type of radioac-tive particles that are emitted from the nuclei of radioactive atoms. Equations are written and balanced for both naturally occurring radioactivity and artificially produced radioactivity. The half-lives of radioisotopes are discussed, and the amount of time for a sample to decay is calculated. Radioisotopes important in the field of nuclear medicine are described. Com-bining Ideas from Chapters 15 and 16 follows as an interchap-ter problem set.

• New Chapter Opener describes the work and career of a radiologist.

• A new Sample Problem, Dating Using Half-Lives, now calculates time elapsed for a bone sample.

• New photos added include a smoke detector and bone in a skeleton used in carbon dating.

Chapter 17, Organic Chemistry, discusses each family of organic compounds, thus forming a basis for understanding the biomolecules of living systems. In this fourth edition, top-ics such as functional groups, reactions of organic compounds, and naming organic acids are now included in earlier chapters on naming molecular compounds and chemical reactions. This organic chapter is now streamlined with an emphasis on nam-ing and drawing formulas of organic compounds from alkanes with substituents to amines and amides.

• New Chapter Opener describes the work and career of a firefighter.

• The skeletal formula for carbon chains has been added.• Drawing a skeletal formula has been added to Sample

Problem 17.2 along with drawing condensed structural formulas.

• A new Guide to Naming Aromatic Compounds has been added.

• Skeletal structures are now included as compounds in Questions and Problems.

• A table of the IUPAC and common names of selected carboxylic acids was added.

• New illustrations for naming esters were added.

Chapter 18, Biochemistry, looks at the chemical structures and reactions of chemicals that occur in living systems. We focus on four types of biomolecules—carbohydrates, lipids, proteins, and nucleic acids—as well as their biochemical reactions. The shape of proteins is related to the activity and regulation of enzyme activity. A discussion of the genetic code and protein synthesis completes the chapter. Combining Ideas from Chap-ters 17 and 18 follows as an interchapter problem set.

• New Chapter Opener describes the work and career of a forensic toxicologist.

• An updated graph of blood glucose levels with time has replaced the previous graph.

• New monosaccharide open-chain structures have been added to Questions and Problems for Carbohydrates.

• The term Haworth Structures is now used for the term cyclic structures for monosaccharides, disaccharides, and polysaccharides.

• The Guide to Drawing Haworth Structures has been rewritten.

• Art added to the introduction of lipids distinguishes between the structures of fatty acids, waxes, triacylglyc-erols, and steroids.

PREFACE xix

• Table 18.2 has been expanded and includes more exam-ples of common fatty acids as well as their skeletal formulas.

• New art and ball-and-stick models of cis-2-butene and trans-2-butene have been added.

• New material on some typical waxes and their condensed structural formulas has been added.

• New art illustrating triacylglycerols has been added.• New art for the olestra molecule has been added.• New art for a steroid and cholesterol has been added.• New art for amino acids and ionized amino acids has

been added.• New single letter abbreviations for amino acids have

been added.• New art for the ribbon models of proteins has been added.• New art for the induced-fit model of enzyme action has

been added.

Instructional PackageBasic Chemistry, Fourth Edition, provides an integrated teach-ing and learning package of support material for both students and professors.

For StudentsThe Study Guide for Basic Chemistry, Fourth Edition, by Karen Timberlake is keyed to the learning goals in the text and designed to promote active learning through a variety of exer-cises with answers as well as practice tests. The Study Guide also contains complete solutions to odd-numbered problems. 1ISBN 03218344372MasteringChemistry® The most advanced, most widely used online chemistry tutorial and homework program is available for the fourth edition of Basic Chemistry. MasteringChem-istry® utilizes the Socratic method to coach students through problem-solving techniques, offering hints and simpler ques-tions on request to help students learn, not just practice. A powerful grade book with diagnostics that gives instructors unprecedented insight into their students’ learning is also avail-able. For the fourth edition, 12 new tutorials have been created to guide students through the most challenging Basic Chemis-try topics and help them make connections between chemical concepts.

Pearson eText offers students the power to create notes, highlight text in different colors, create bookmarks, zoom, and view single or multiple pages. Access to the Pearson eText for Basic Chemistry, Fourth Edition, is available for purchase either as a stand-alone item 1ISBN 03218342912 or within Mastering Chemistry®. 1ISBN 032183433X2

Laboratory Manual by Karen Timberlake This best-selling lab manual coordinates 35 experiments with the topics in Basic Chemistry, Fourth Edition, and uses new terms during the lab and explores chemical concepts. Laboratory investiga-tions develop skills of manipulating equipment, reporting data, solving problems, making calculations, and drawing conclu-sions. These labs are also available within Pearson Custom Library, which gives instructors the power to create a custom text by selecting content from our course-specific collections. 1ISBN 03218118522For InstructorsMasteringChemistry® MasteringChemistry® is the first adaptive-learning online homework and tutorial system. Instructors can create online assignments for their students by choosing from a wide range of items, including end-of-chapter problems and research-enhanced tutorials. Assignments are automatically graded with up-to-date diagnostic information, helping instruc-tors pinpoint where students struggle either individually or as a class as a whole. For the fourth edition, new tutorials have been created to guide students through the most challenging Basic Chemistry topics and help them make connections between chemical concepts.

Instructor Solutions Manual Prepared by Mark Quirie, this manual highlights chapter topics. It contains complete solu-tion setups and answers to all the problems in the text. 1ISBN 03218344452Instructor’s Resource Materials for Basic Chemistry, Fourth Edition This resource includes all the art, photos, and tables from the book in JPG format for use in classroom projec-tion or when creating study materials and tests. In addition, the instructors can access the PowerPointTM lecture outlines, featuring over 2000 slides. Also available are downloadable files of the Instructor Solutions Manual and a set of “clicker questions” designed for use with classroom-response systems. 1ISBN 03218094832TestGen Test Bank Prepared by William Timberlake, this resource includes more than 1600 questions in multiple-choice, matching, true/false, and short-answer format. 1ISBN 032183447X2Online Instructor Manual for Laboratory Manual This manual contains answers to report pages for the Laboratory Manual. 1ISBN 03218128592

Also visit the Pearson Education catalog page for Timberlake’s Basic Chemistry, Fourth Edition, at www.pearsonhighered.com to download available instructor supplements.

xx PREFACE

AcknowledgmentsThe preparation of a new text is a continuous effort of many people. As in our work on other textbooks, we are thankful for the support, encouragement, and dedication of many people who put in hours of tireless effort to produce a high-quality book that provides an outstanding learning package. The edito-rial team at Pearson Publishing has done an exceptional job. We want to thank, Adam Jaworski, editor in chief, who supported our vision of this fourth edition and the development of new math remediation strategies with Chapter Readiness, Key Math Skills, and Core Chemistry Skills, which appear throughout the chapter along with their reviews at the end of each chapter and with the new Analyze the Problem feature that clarifies the components of a word problem for problem solving. We also appreciate the addition of new Concept Checks, more Guides to Problem Solving, new Chemistry Links to Health, Chemis-try Link to History, Chemistry Link to Industry, and Chemistry Link to the Environment boxes, and new problems in Under-standing the Concepts and Combining Ideas.

We much appreciate all the wonderful work of Jessica Moro, project editor, who was like an angel encouraging us at each step, while skillfully coordinating reviews, art, web site materials, and all the things it takes to make a book come together. We appreciate the work of Beth Sweeten, project manager, and Andrea Stefanowicz of PreMediaGlobal, who brilliantly coordinated all phases of the manuscript to the final pages of a beautiful book. Thanks to Mark Quirie, manu-script and accuracy reviewer, and Betty Pessagno, copy editor, who precisely analyzed and edited the initial and final manu-scripts and pages to make sure the words and problems were correct to help students learn chemistry. Their keen eyes and

thoughtful comments were extremely helpful in the develop-ment of this text.

We are especially proud of the art program in this text, which lends beauty and understanding to chemistry. We would like to thank Connie Long and Derek Bacchus, art director and book designer, whose creative ideas provided the outstand-ing design for the cover and pages of the book. Eric Schrader, photo researcher, was invaluable in researching and selecting vivid photos for the text so that students can see the beauty of chemistry. Thanks also to Bio-Rad Laboratories for their cour-tesy and use of KnowItAll ChemWindows, drawing software that helped us produce chemical structures for the manuscript. The macro-to-micro illustrations designed by Production Solu-tions and Precision Graphics give students visual impressions of the atomic and molecular organization of everyday things and are a fantastic learning tool. We want to thank Martha Ghent for the hours spent proofreading all the pages. We also appreciate all the hard work put in by the marketing team in the field and Jonathan Cottrell, marketing manager.

We are extremely grateful to an incredible group of peers for their careful assessment of all the new ideas for the text; for their suggested additions, corrections, changes, and deletions; and for providing an incredible amount of feedback about improvements for the book. In addition, we appreciate the time scientists took to let us take photos and discuss their work with them. We admire and appreciate every one of you.

If you would like to share your experience with chemis-try, or have questions and comments about this text, we would appreciate hearing from you.

Karen and Bill TimberlakeEmail: [email protected]

xxi

Reviewers

Fourth Edition ReviewersEdward AlexanderSan Diego Mesa College

Kristen CaseyAnne Arundel Community College

James FalenderCentral Michigan University

Tamara HannaTexas Tech University

Shawn KormanRio Salado Community College

Robin LaseyArkansas Tech University

Lynda NelsonUniversity of Arkansas Fort Smith

Mary RepaskeCincinnati State Technical and Community College

Mitchell RobertsonSouthwestern Illinois College

Alan ShermanMiddlesex County College

Trent VorlicekMinnesota State University-Mankato

Joy WalkerTruman College

Marie WolffJoliet Junior College

Regina ZibuckWayne State University

Accuracy ReviewerMark QuirieAlgonquin College

Previous Edition ReviewersMaher AtteyaGeorgia Perimeter College

Pamela GoodmanMoraine Valley Community College

David NachmanMesa Community College

MaryKay OrgillUniversity of Nevada, Las Vegas

Mark QuirieAlgonquin College

Ben RutherfordWashington State Community College

About the Author

KAREN TIMBERLAKE is Professor Emerita of Chemistry at Los Angeles Valley College, where she taught chemistry for allied health and preparatory chemistry for 36 years. She received her bachelor’s degree in chemistry from the University of Washington and her master’s degree in biochemistry from the University of California at Los Angeles.

Professor Timberlake has been writing chemistry textbooks for 40 years. During that time, her name has become associated with the strategic use of pedagogical tools that promote student success in chemistry and the application of chemistry to real-life situations. More than one million students have learned chemistry using texts, laboratory manuals, and study guides written by Karen Timberlake. In addition to Basic Chemistry, Fourth Edition, she is also the author of Chemistry: An Introduction to General, Organic, and Biological Chemistry, Eleventh Edition, and General, Organic, and Biological Chemistry: Structures of Life, Fourth Edition.

Professor Timberlake belongs to numerous scientific and educational organizations including the American Chemical Society 1ACS2 and the National Science Teachers Association 1NSTA2. She was the Western Regional Winner of Excellence in College Chemistry Teaching Award given by the Chemical Manufacturers Association. She received the McGuffey Award in Physical Sciences from the Textbook Authors Association for her textbook

Chemistry: An Introduction to General, Organic, and Biological Chemistry, Eighth Edition. She received the “Texty” Textbook Excellence Award from the Textbook Authors Association for the first edition of Basic Chemistry. She has participated in education grants for science teaching including the Los Angeles Collaborative for Teaching Excellence 1LACTE2 and a Title III grant at her college. She speaks at conferences and educational meetings on the use

of student-centered teaching methods in chemistry to promote the learning success of students.

Her husband, William Timberlake, who is the coauthor of this text, is Professor Emeritus of Chemistry at Los Angeles Harbor College, where he taught preparatory and organic chemistry for 36 years. He received his bachelor’s degree in chemistry from Carnegie Mellon University and his master’s degree in organic chemistry from the University of California at Los Angeles. When the Professors Timberlake are not writing textbooks, they relax by hiking, traveling, trying new restaurants, cooking, playing tennis, and taking care of their grandchildren, Daniel and Emily.

We dedicate this book to

• Our son, John, daughter-in-law, Cindy, grandson, Daniel, and granddaughter, Emily, for the precious things in life

• The wonderful students over many years whose hard work and commitment always motivated us and put purpose in our writing

DEDICATION

Students learn chemistry using real-world examples

Description

Chapters begin with storiesinvolving careers in fields such as nursing, dentistry, agriculture, engineering, exercise physiology, and veterinary sciences.

Page

69

Feature

NEW! Chapter Opener

Benefit

Shows you how health professionals use chemistry every day

“Discovery consists of seeing what everybody has seen and thinking what nobody has thought.”—Albert Szent-Györgyi

Chemistry Links to Health apply chemical concepts to relevant topics of health and medicine such as weight loss and weight gain, trans fats, anabolic steroids, alcohol abuse, blood buffers, kidney dialysis, and cancer.

Chemistry Links to the Environment relate chemistry to environmental topics such as global warming, radon in our homes, acid rain, and pheromones.

Chemistry Links to Industry describe industrial and commercial applications while Chemistry Links to History describe the historical development of chemical ideas.

Macro-to-Micro Art utilizes photographs and drawings to illustrate the atomic structure of chemical phenomena.

259

56

106, 4

245

UPDATED! Chemistry Link to Health

Chemistry Links to the Environment

Chemistry Links to Industry and Chemistry Link to History

Provides you with connections that illustrate the importance of understanding chemistry in real life health and medical situations

Helps you extend your understanding of the impact of chemistry on the environment

Helps you understand the importance of chemistry in industry and history

Helps you connect the world of atoms and molecules to the macroscopic world

UPDATED! Macro-to-Micro Art

Mg2+ Na+Cl– PO43–

Feature

Learning Goals

Writing Style

UPDATED! Concept Maps

NEW! Key Math Skills

NEW! Core Chemistry Skills

UPDATED! Art Program

UPDATED! Chapter Reviews

Description

Learning Goals at the beginning and end of each section identify the key concepts for that section and provide a roadmap for your study.

Timberlake’s accessible writing style is based on careful development of chemical concepts suited to the skills and backgrounds of students in preparatory chemistry.

Concept Maps at the end of each chapter show how all the key concepts fit together.

The art program is beautifully rendered, pedagogically effective, and includes questions with all the figures.

The Chapter Reviews include Learning Goals and new visual thumbnails to summarize the key points in each section.

Benefit

Helps you focus your studying by emphasizing what is most important in each section

Helps you understand new terms and chemical concepts

Encourages learning by providing a visual guide to the interrelationship among all the concepts in each chapter

Helps you master the basic quantitative skills to succeed in preparatory chemistry

Helps you master the basic problem-solving skills needed to succeed in chemistry

Helps you think critically using photos and illustrations

Helps you determine your mastery of the chapter concepts and study for your tests

Page

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498

Engage students in the world of chemistry

61

“I never teach my pupils; I only attempt to provide the conditions in which they can learn.”—Albert Einstein

Key Math Skills provide practice problems related to basic math.

Core Chemistry Skills provide content crucial to problem-solving strategies related to chemistry.

CORE CHEMISTRY SKILL

Counting Significant Figures

Feature

UPDATED! Guides to Problem Solving 1GPS2

End-of-Section Questions and Problems

UPDATED! Concept Checks

UPDATED! Sample Problems with Study Checks

Description Benefit Page

31

34

88

214

Guides to Problem Solving 1GPS2 illustrate the steps needed to solve problems.

Questions and Problems are placed at the end of each section. Problems are paired and the Answers to the odd-numbered problems are given at the end of each chapter.

Concept Checks that transition from conceptual ideas to problem- solving strategies are placed throughout each chapter.

Allows you to check your understanding of new chemical terms and ideas as they are introduced in the chapter

Provides the intermediate steps to guide you successfully through each type of problem

UPDATED! Understanding the Concepts

273Understanding the Concepts are questions with visual representations placed at the end of each chapter.

Builds an understanding of newly learned chemical concepts

Challenge Questions 276Challenge Questions at the end of each chapter provide complex questions.

UPDATED! Combining Ideas 102Combining Ideas are sets of integrated problems that are placed after every 2–4 chapters.

Tests your understanding of the concepts from previous chapters by integrating topics

Many tools show students how to solve problems

UPDATED! Additional Questions and Problems

275Additional Questions and Problems at the end of chapter provide further study and application of the topics from the entire chapter.

Promotes critical thinking

NEW! Analyze the Problems 214Analyze the Problems feature now included in Sample Problem Solutions convert information in a word problem into components for problem solving.

Helps you identify and utilize the components within a word problem to set up a solution strategy

“The whole art of teaching is only the art of awakening the natural curiosity of young minds.”—Anatole France

Visually guides you step-by-step through each problem-solving strategy

Encourages you to become involved immediately in the process of problem solving

Sample Problems illustrate worked-out solutions with step-by-step explanations and required calculations. Study Checks associated with each Sample Problem allow you to check your problem-solving strategies.

Promotes critical thinking, group work, and cooperative learning environments

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L O O K I N G A H E A D1.1 Chemistry and Chemicals1.2 Scientific Method: Thinking Like

a Scientist1.3 Learning Chemistry: A Study Plan1.4 Learning Chemistry: Key Math Skills

A. Identifying Place ValuesB. Using Positive and Negative Numbers

in CalculationsC. Calculating a PercentageD. Solving EquationsE. Interpreting a Line Graph

Chemistry in Our Lives

Sarah works as a forensic scientist where she applies scientific procedures to evidence from law enforcement agencies. Such evidence may include blood, hair, or fiber from clothing found at a crime scene. At work, she analyzes blood for the presence of drugs, poisons, and alcohol. She prepares tissues for typing factors and for DNA analysis. Her lab partner Mark is working on matching characteristics of a bullet to a firearm found at a crime scene. He is also using fingerprinting techniques to identify the victim of a crime.

A female victim is found dead in her home. The police suspect that she was murdered, so samples of her blood and stomach contents are sent to Sarah. Using a variety of qualitative and quantitative tests, Sarah finds traces of ethylene glycol. The qualitative tests show that ethylene glycol is present, while the quantitative tests indicate the amount of ethylene glycol the victim has in her system. Sarah determines that the victim was poisoned when she ingested ethylene glycol placed in an alcoholic beverage. Since the initial symptoms of ethylene glycol poisoning are similar to being intoxicated, the victim was unaware of the poisoning.

1

1

The alcohol in beverages undergoes oxidation reactions to other compounds that are eliminated by the body. When ethylene glycol is oxidized, the products can cause renal failure and may be toxic to the body.

Career: Forensic ScientistMost forensic scientists work in crime laboratories that are part of city or county legal systems where they analyze bodily fluids and tissue samples collected by crime scene investigators. In analyzing these samples, a forensic scientist identifies the presence or absence of specific chemicals within the body to help solve the criminal case. Some of the chemicals they look for include alcohol, illegal or prescription drugs, poisons, arson debris, metals, and various gases such as carbon monoxide. In order to identify these substances, a variety of chemical instruments and highly specific methodologies are used. A forensic scientist also analyzes samples from criminal suspects, athletes, and potential employees. They also work on cases involving environmental contamination and animal samples for wildlife crimes. A forensic scientist usually has a bachelor’s degree that includes courses in math, chemistry, and biology.

2 CHAPTER 1 CHEMISTRY IN OUR LIVES

Now that you are in a chemistry class, you may be wondering what you will be learning. What questions in science have you been curious about? Perhaps you are interested in how smog is formed, what causes ozone depletion, how nails form

rust, or how aspirin relieves a headache. Just like you, chemists are curious about the world we live in.

• How does car exhaust produce the smog that hangs over our cities? One com-ponent of car exhaust is nitrogen oxide 1NO2, which forms in car engines where high temperatures convert nitrogen gas (N2) and oxygen gas (O2) to NO. In chemistry, these reactions are written in the form of equations such as N21g2 + O21g2 h 2NO1g2.

• Why has the ozone layer been depleted in certain parts of the atmosphere? During the 1970s, scientists discovered that substances called chlorofluorocarbons 1CFCs2 were associated with the depletion of ozone. As CFCs are broken down by ultra-violet 1UV2 light, chlorine 1Cl2 is released that causes the breakdown of ozone (O3) molecules and destroys the ozone layer.

Cl1g2 + O31g2 h ClO1g2 + O21g2Molecules of NO2

The chemical reaction of NO with oxygen in the air forms NO2, which produces the reddish brown color of smog.

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1.1 CHEMISTRY AND CHEMICALS 3

• Why does aspirin relieve a headache? When a part of the body is injured, substanc-es called prostaglandins are produced, which cause inflammation and pain. Aspirin acts to block the production of prostaglandins, thereby reducing inflammation, pain, and fever.

Chemists perform many different kinds of research. Some design new fuels and more efficient ways to use them. Researchers in the medical field develop new treatments for diabetes, genetic defects, cancer, AIDS, and other diseases. Researchers in the environmental field study the ways in which human development impacts the environment and develop pro-cesses that help reduce environmental degradation. For the researcher in the laboratory, the physician in the dialysis unit, the environmental chemist, or the agricultural scientist, chemistry plays a central role in understanding problems, assessing possible solutions, and making important decisions.

CHAPTER READINESS

Key Math Skills

◆ Identifying Place Values (1.4A)

◆ Using Positive and Negative Numbers in Calculations (1.4B)

◆ Calculating a Percentage (1.4C)

◆ Solving Equations (1.4D)

◆ Interpreting a Line Graph (1.4E)

1.1 Chemistry and ChemicalsChemistry is the study of the composition, structure, properties, and reactions of matter. Matter is another word for all the substances that make up our world. Perhaps you imagine that chemistry takes place only in a laboratory where a chemist is working in a white coat and goggles. Actually, chemistry happens all around you every day and has an impact on everything you use and do. You are doing chemistry when you cook food, add bleach to your laundry, or start your car. A chemical reaction has taken place when silver tarnishes or an antacid tablet fizzes when dropped into water. Plants grow because chemical reac-tions convert carbon dioxide, water, and energy to carbohydrates. Chemical reactions take place when you digest food and break it down into substances that you need for energy and health.

Branches of ChemistryThe field of chemistry is divided into several branches. General chemistry is the study of the composition, properties, and reactions of matter. Organic chemistry is the study of sub-stances that contain the element carbon. Biological chemistry is the study of the chemical reactions that take place in biological systems.

Today chemistry is often combined with other sciences, such as geology and physics, to form cross-disciplines such as geochemistry and physical chemistry. Geochemistry is the study of the chemical composition of ores, soils, and minerals of the surface of the Earth and other planets. Physical chemistry is the study of the physical nature of chemical systems, including energy changes.

Antacid tablets undergo a chemical reaction when dropped into water.

L E A R N I N G G O A LDefine the term chemistry and identify substances as chemicals.

A geochemist collects newly erupted lava samples from Kilauea Volcano, Hawaii.

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Toothpaste is a combination of many chemicals.

Chemistry Link to HistoryEARLY CHEMISTS: THE ALCHEMISTS

For many centuries, chemists have studied changes in matter. From the time of the ancient Greeks to about the sixteenth century, early scien-tists, called alchemists, described matter in terms of four components of nature: earth, air, fire, and water. These components had the quali-ties of hot, cold, wet, or dry. By the eighth century, alchemists believed that they could rearrange these qualities to change metals such as copper and lead into gold and silver. They searched for an unknown substance called a philosopher’s stone, which they thought would turn metals into gold as well as prolong youth and postpone death. Although these efforts failed, the alchemists did provide information on the processes and chemical reactions involved in the extraction of metals from ores. During the many centuries that alchemy flourished, alchemists made observations of matter and identified the properties of many substances. They also designed some of the first laboratory equipment and developed early laboratory procedures.

The alchemist Paracelsus 11493–15412 thought that alchemy should be about preparing new medicines, not about producing gold. Using observation and experimentation, he proposed that a healthy body was regulated by a series of chemical processes that could be unbalanced by certain chemical compounds and rebalanced by using minerals and medicines. For example, he determined that inhaled dust, not underground spirits, caused lung disease in miners. He also thought that goiter was a problem caused by contaminated water, and he treated syphilis with compounds of mercury. His opinion of

medicines was that the right dose makes the difference between a poison and a cure. Today this idea is part of the risk–benefit assess-ment of medicine. Paracelsus changed alchemy in ways that helped to establish modern medicine and chemistry.

Alchemists in the Middle Ages developed laboratory procedures.

Swiss alchemist Paracelsus 11493–15412 believed that chemicals and minerals could be used as medicines.

ChemicalsA chemical is a substance that always has the same composition and properties wherever it is found. All the things you see around you are composed of one or more chemicals. Chemical processes take place in chemistry laboratories, manufacturing plants, and phar-maceutical labs as well as every day in nature and in our bodies. Often the terms chemical and substance are used interchangeably to describe a specific type of matter.

Every day, you use products containing substances that were developed and prepared by chemists. Soaps and shampoos contain chemicals that remove oils on your skin and scalp. When you brush your teeth, the substances in toothpaste clean your teeth, prevent plaque formation, and stop tooth decay. Some of the chemicals used to make toothpaste are listed in Table 1.1.

TABLE 1.1 Chemicals Commonly Used in Toothpaste

Chemical Function

Calcium carbonate Used as an abrasive to remove plaqueSorbitol Prevents loss of water and hardening of toothpasteSodium lauryl sulfate Used to loosen plaqueTitanium dioxide Makes toothpaste white and opaqueTriclosan Inhibits bacteria that cause plaque and gum diseaseSodium fluorophosphate Prevents formation of cavities by strengthening tooth

enamel with fluorideMethyl salicylate Gives toothpaste a pleasant wintergreen flavor

In cosmetics and lotions, chemicals are used to moisturize, prevent deterioration of the product, fight bacteria, and thicken the product. Your clothes may be made of natural mate-rials such as cotton or synthetic substances such as nylon or polyester. Perhaps you wear a

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1.1 CHEMISTRY AND CHEMICALS 5

FIGURE 1.1 Many of the items found in a kitchen are chemicals or products of chemical reactions.Q What are some other chemi-

cals found in a kitchen?

Silicon dioxide1glass2 Metal alloy

Chemically treatedwater

Natural gasNatural polymers

Fruits grownwith fertilizersand pesticides

CONCEPT CHECK 1.1 Chemicals

Why is the copper in a copper wire an example of a chemical?

ANSWER

Copper has the same composition and properties wherever it is found. Thus, copper is a chemical.

1.1 Chemistry and Chemicals

L E A R N I N G G O A L : Define the term chemistry and identify substances as chemicals.In every chapter, odd-numbered exercises in the Questions and Problems are paired with even-numbered exercises. The answers for the magenta, odd-numbered Questions and Problems are given at the end of this chapter. The complete solutions to the odd-numbered Questions and Problems are in the Student Solutions Manual.

1.1 Write a one-sentence definition for each of the following:a. chemistry b. chemical

1.2 Ask two of your friends 1not in this class2 to define the terms in Problem 1.1. Do their answers agree with the definitions you provided?

1.3 Obtain a bottle of multivitamins and read the list of ingredi-ents. What are four chemicals from the list?

1.4 Obtain a box of breakfast cereal and read the list of ingredi-ents. What are four chemicals from the list?

1.5 Read the labels on some items found in your medicine cabinet. What are the names of some chemicals contained in those items?

1.6 Read the labels on products used to wash and clean your car. What are the names of some chemicals contained in those products?

1.7 Pesticides are chemicals. Give one advantage and one dis advantage of using pesticides.

1.8 Sugar is a chemical. Give one advantage and one disadvantage of eating sugar.

QUESTIONS AND PROBLEMS

SAMPLE PROBLEM 1.1 Everyday Chemicals

Identify the chemical in each of the following statements:

a. Soda cans are made from aluminum.b. Salt 1sodium chloride2 is used to preserve meat and fish.c. Sugar 1sucrose2 is used as a sweetener.

SOLUTIONa. aluminum b. salt 1sodium chloride2 c. sugar 1sucrose2STUDY CHECK 1.1Which of the following are chemicals?

a. iron b. tin c. a low temperature d. water

The answers to all of the Study Checks can be found at the end of each chapter.

ring or watch made of gold, silver, or platinum. Your breakfast cereal is probably fortified with iron, calcium, and phosphorus, while the milk you drink is enriched with vitamins A and D. Antioxidants are chemicals added to food to prevent it from spoiling. Some of the chemicals you may encounter when you cook in the kitchen are shown in Figure 1.1.

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1.2 Scientific Method: Thinking Like a ScientistWhen you were very young, you explored the things around you by touching and tast-ing. As you grew, you asked questions about the world in which you live. What is light-ning? Where does a rainbow come from? Why is water blue? As an adult, you may have wondered how antibiotics work or why vitamins are important to your health. Every day, you ask questions and seek answers to organize and make sense of the world around you.

When the late Nobel Laureate Linus Pauling described his student life in Oregon, he recalled that he read many books on chemistry, mineralogy, and physics. “I mulled over the properties of materials: why are some substances colored and others not, why are some minerals or inorganic compounds hard and others soft?” He said, “I was building up this tremendous background of empirical knowledge and at the same time asking a great number of questions.” Linus Pauling won two Nobel Prizes: the first, in 1954, was in chemistry for his work on the nature of chemical bonds and the deter-mination of the structures of complex substances; the second, in 1962, was the Peace Prize.

Scientific MethodAlthough the process of trying to understand nature is unique to each scientist, a set of general principles, called the scientific method, helps to describe how a scientist thinks.

1. Observations. The first step in the scientific method is to observe, describe, and measure an event in nature. Observations based on measurements are called data.

2. Hypothesis. After sufficient data are collected, a hypothesis is proposed, which states a possible interpretation of the observations. The hypothesis must be stated in a way that it can be tested by experiments.

3. Experiments. Experiments are tests that determine the validity of the hypothesis. Often, many experiments are performed to test the hypothesis, and a large amount of information is collected. Many experiments are needed to support the origi-nal hypothesis. However, if just one experiment produces a different result than predicted by the hypothesis, a modified hypothesis must be proposed. Then new experiments are conducted to test the new hypothesis.

4. Theory. When experiments are repeated by many scientists with consistent results, the hypothesis may be confirmed. Consequently, that hypothesis may become a theory. Even then, a theory continues to be tested and, based on new experimental results, may need to be modified or replaced. Then the cycle of the scientific method begins again with the proposal of a new hypothesis.

Using the Scientific Method in Everyday LifeYou may be surprised to realize that you use the scientific method in your everyday life. Suppose you visit a friend in her home. Soon after you arrive, your eyes start to itch and you begin to sneeze. Then you observe that your friend has a new cat. Perhaps you ask yourself why you are sneezing and you form the hypothesis that you are allergic to cats. To test your hypothesis, you leave your friend’s home. If the sneezing stops, per-haps your hypothesis is correct. You test your hypothesis further by visit-ing another friend who also has a cat. If you start to sneeze again, your experimental results support your hypothesis that you are allergic to cats. However, if you continue sneezing after you leave your friend’s home, your hypothesis is not supported. Now you need to form a new hypoth-esis, which could be that you have a cold.

L E A R N I N G G O A LDescribe the activities that are part of the scientific method.

Linus Pauling won the Nobel Prize in chemistry in 1954.

Students make observations in the chemistry laboratory.

The scientific method develops a theory using observa-tions, hypotheses, and experiments.

Hypothesis Hypothesischanged ifexperimentsdo not support it.

Theory modified if additionalexperimentsdo not support it.

Experiments

Theory

Observations

Scientific Method

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1.2 SCIENTIFIC METHOD: THINKING LIKE A SCIENTIST 7

A silver tray tarnishes when exposed to the air.

CONCEPT CHECK 1.2 Scientific Method

Identify each of the following as an observation 1O2, a hypothesis 1H2, or an experiment 1E2:a. Drinking coffee at night keeps me awake.b. If I stop drinking coffee in the afternoon, I will be able to sleep at night.c. I will try drinking coffee only in the morning.

ANSWERa. Describing what happens when I drink coffee is an observation 1O2.b. Describing what may happen if I stop drinking coffee in the afternoon is a

hypothesis 1H2.c. Changing the time for drinking coffee is an experiment 1E2.

SAMPLE PROBLEM 1.2 Scientific Method

Identify each of the following statements as an observation 1O2 or a hypothesis 1H2:

a. A silver tray turns a dull gray color when left uncovered.b. North of the equator, it is warmer in summer than in winter.c. Ice cubes float in water because they are less dense.

SOLUTIONa. observation 1O2b. observation 1O2c. hypothesis 1H2STUDY CHECK 1.2The following statements are found in a student’s notebook. Identify each of the following as an observation 1O2, a hypothesis 1H2, or an experiment 1E2:a. “Today I placed two tomato seedlings in the garden, and two more in a closet. I will

give all the plants the same amount of water and fertilizer.”b. “After 50 days, the tomato plants in the garden are 3 ft high with green leaves. The

plants in the closet are 8 in. tall and yellow.”c. “Tomato plants need sunlight to grow.” Tomato plants grow faster when

placed in the sun.

Through observation you may determine that you are allergic to cat hair and dander.

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1.2 Scientific Method: Thinking Like a Scientist

L E A R N I N G G O A L : Describe the activities that are part of the scientific method.1.9 Define each of the following terms of the scientific method:

a. hypothesis b. experimentc. theory d. observation

1.10 Identify each of the following activities in the scientific method as an observation 1O2, a hypothesis 1H2, an experi-ment 1E2, or a theory 1T2:a. Formulate a possible explanation for your experimental

results.b. Collect data.


Chemistry Link to the EnvironmentDDT—GOOD PESTICIDE, BAD PESTICIDE

DDT 1Dichlorodiphenyltrichloroethane2 was once one of the most commonly used pesticides. DDT is an example of organic com-pounds, which typically are composed of the elements of carbon 1C2 and hydrogen 1H2. In a molecule of DDT, there are 14 carbon atoms and 9 hydrogen atoms, as well as 5 chlorine atoms. The hydrocarbon portion makes DDT insoluble in water, and the Cl atoms make DDT difficult to break down.

Although DDT was first synthesized in 1874, it was not used as an insecticide until 1939. Before DDT was widely used, insect-borne diseases such as malaria and typhus were rampant in many parts of the world. Paul Müller, who discovered that DDT was an effective pesticide, was recognized for saving many lives and received the Nobel Prize in Physiology or Medicine in 1948. DDT was considered the ideal pesticide because it was toxic to many insects, had a low toxicity to humans and animals, and was inexpensive to prepare.

In the United States, DDT was used extensively in homes as well as on crops, such as cotton and soybeans. Because of its stable chem-ical structure, DDT did not break down quickly in the environment, which meant that it did not have to be applied as often. At first, every-one was pleased with DDT as crop yields increased and diseases such as malaria and typhus were controlled.

However, by the early 1950s, problems attributed to DDT began to surface. Insects were becoming more resistant to the pesticide. At the same time, the public was increasingly concerned about the long-term impact of a substance that could remain in the environment for many years. The metabolic systems of humans and animals cannot break down DDT, which is soluble in fats but not in water and is stored in the fatty tissues of the body. Although the concentration of DDT applied to crops was very low, runoff containing DDT reached the oceans, where the DDT was absorbed by fish.

When birds such as the Brown Pelicans in Florida and Califor-nia consumed fish contaminated with DDT, the amount of calcium in their eggshells was significantly reduced. As a result, incubating eggs cracked open early, causing offspring to die. Due to this difficulty with reproduction, the populations of birds such as the Brown Pelican dropped significantly and they became endangered.

A 1947 advertisement recommends the household use of DDT.

The Brown Pelican was once an endangered species due to the use of DDT.

A field is sprayed with pesticide.

By 1972, DDT was banned in the United States. Since then, the population of Brown Pelicans has increased, and they are no longer considered endangered. Today new types of pesticides, which are more water-soluble and break down faster in the environment, have replaced the long-lasting pesticides such as DDT. However, these new pesticides are much more toxic to humans.

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1.3 LEARNING CHEMISTRY: A STUDY PLAN 9

1.3 Learning Chemistry: A Study PlanHere you are taking chemistry, perhaps for the first time. Whatever your reasons for choos-ing to study chemistry, you can look forward to learning many new and exciting ideas.

Features in This Text Help You Study ChemistryThis text has been designed with study features to complement your individual learning style. On the inside of the front cover is a periodic table of the elements. On the inside of the back cover are tables that summarize useful information needed throughout your study of chem-istry. Each chapter begins with Looking Ahead, which outlines the topics in the chapter. At the end of the text, there is a comprehensive Glossary and Index, which lists and defines key terms used in the text. Key Math Skills that will be helpful to your understanding of chemical calculations are reviewed. Core Chemistry Skills that are critical to learning chemistry are indicated by icons in the margin, and summarized at the end of each chapter. In the Chapter Readiness list at the beginning of every chapter, the Key Math Skills and Core Chemistry Skills from previous chapters related to the current chapter concepts are highlighted for your review.

Before you begin reading, obtain an overview of a chapter by reviewing the topics in Looking Ahead. As you prepare to read a section of the chapter, look at the section title and turn it into a question. For example, for Section 1.1, “Chemistry and Chemicals,” you could ask “What is chemistry?” or “What are chemicals?”. Throughout each chapter, you will find Concept Checks that will help you understand key ideas. When you come to a Sample Prob-lem, take the time to work it through and compare your solution to the one provided. Then try the associated Study Check. Many Sample Problems are accompanied by a Guide to Problem Solving 1GPS2, which gives the steps needed to work the problem. In some Sample Problems, an Analyze the Problem feature shows how to organize the data in the word prob-lem to obtain a solution. At the end of each chapter section, you will find a set of Questions and Problems that allows you to apply problem solving immediately to the new concepts.

Throughout each chapter, boxes titled “Chemistry Link to Health,” “Chemistry Link to History,” “Chemistry Link to Industry,” and “Chemistry Link to the Environment” help you connect the chemical concepts you are learning to real-life situations. Many of the figures and diagrams use macro-to-micro illustrations to depict the atomic level of

L E A R N I N G G O A LDevelop a study plan for learning chemistry.

c. Design an experimental plan that will give new informa-tion about a problem.

d. State a generalized summary of your experimental results.

1.11 Identify each activity, a–f, as an observation 1O2, a hypoth-esis 1H2, an experiment 1E2, or a theory 1T2. At a popular restaurant, where Chang is the head chef, the following occurred:a. Chang determined that sales of the house salad had dropped.b. Chang decided that the house salad needed a new dressing.c. In a taste test, Chang prepared four bowls of lettuce, each

with a new dressing: sesame seed, olive oil and balsamic vinegar, creamy Italian, and blue cheese.

d. The tasters rated the sesame seed salad dressing as the favorite.

e. After two weeks, Chang noted that the orders for the house salad with the new sesame seed dressing had doubled.

f. Chang decided that the sesame seed dressing improved the sales of the house salad because the sesame seed dressing enhanced the taste.

1.12 Identify each activity, a–f, as an observation 1O2, a hypoth-esis 1H2, an experiment 1E2, or a theory 1T2. Lucia wants to develop a process for dyeing shirts so that the color will not fade when the shirt is washed. She proceeds with the following activities:a. Lucia notices that the dye in a design fades when the shirt

is washed.b. Lucia decides that the dye needs something to help it

combine with the fabric.c. She places a spot of dye on each of four shirts and then

places each one separately in water, salt water, vinegar, and baking soda and water.

d. After one hour, all the shirts are removed and washed with a detergent.

e. Lucia notices that the dye has faded on the shirts in water, salt water, and baking soda, while the dye did not fade on the shirt soaked in vinegar.

f. Lucia thinks that the vinegar binds with the dye so it does not fade when the shirt is washed.

Customers rated the sesame seed dressing as the best.

KEY MATH SKILL


Analyze the Problem

Given Need

165 lb kilograms

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organization of ordinary objects. These visual models illustrate the concepts described in the text and allow you to “see” the world in a microscopic way.

At the end of each chapter, you will find several study aids that complete the chapter. Chapter Reviews provide a summary and Concept Maps show the connections between important topics. The Key Terms, which are in boldface type within the chapter, are listed with their definitions. Understanding the Concepts, a set of questions that use art and models, helps you visualize concepts. Additional Questions and Problems and Challenge Problems provide additional exercises to test your understanding of the topics in the chapter. The problems are paired, which means that each of the odd-numbered problems is matched to the following even-numbered problem. The answers to all the Study Checks, as well as the answers to all the odd-numbered problems are provided at the end of the chapter. If the answers provided match your answers, you most likely understand the topic; if not, you need to study the section again.

After some chapters, problem sets called Combining Ideas test your ability to solve problems containing material from more than one chapter.

Using Active LearningA student who is an active learner continually interacts with the chemical ideas while reading the text, working problems, and attending lectures. Let’s see how this is done.

As you read and practice problem solving, you remain actively involved in studying, which enhances the learning process. In this way, you learn small bits of information at a time and establish the necessary foundation for understanding the next section. You may also note questions you have about the reading to discuss with your professor or laboratory instructor. Table 1.2 summarizes these steps for active learning. The time you spend in a lecture is also a useful learning time. By keeping track of the class schedule and reading the assigned material before a lecture, you become aware of the new terms and concepts you need to learn. Some questions that occur during your reading may be answered during the lecture. If not, you can ask your professor for further clarification.

TABLE 1.2 Steps in Active Learning

1. Read each Learning Goal for an overview of the material.2. Form a question from the title of the section you are going to read.3. Read the section, looking for answers to your question.4. Self-test by working Concept Checks, Sample Problems, and Study Checks.5. Complete the Questions and Problems that follow that section, and check the answers

for the magenta odd-numbered problems.6. Proceed to the next section and repeat the steps.

Many students find that studying with a group can be beneficial to learning. In a group, students motivate each other to study, fill in gaps, and correct misunderstandings by teaching and learning together. Studying alone does not allow the process of peer correction. In a group, you can cover the ideas more thoroughly as you discuss the reading and problem solve with other students. You may find that it is easier to retain new material and new ideas if you study in short sessions throughout the week rather than all at once. Waiting to study until the night before an exam does not give you time to understand concepts and practice problem solving.

Making a Study PlanAs you embark on your journey into the world of chemistry, think about your approach to studying and learning chemistry. You might consider some of the ideas in the following list. Check those ideas that will help you successfully learn chemistry. Commit to them now. Your success depends on you.

My study plan for learning chemistry will include the following:

________ reading the chapter before lecture________ going to lecture________ reviewing the Learning Goals________ keeping a problem notebook

Studying in a group can be beneficial to learning.

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1.3 LEARNING CHEMISTRY: A STUDY PLAN 11

________ reading the text as an active learner________ working the Questions and Problems following each section and checking

answers at the end of the chapter________ being an active learner in lecture________ organizing a study group________ seeing the professor during office hours________ reviewing Key Math Skills and Core Chemistry Skills________ attending review sessions________ organizing my own review sessions________ studying as often as I can

CONCEPT CHECK 1.3 A Study Plan for Chemistry

What are some advantages to studying in a group?

ANSWERIn a group, students motivate and support each other, fill in gaps, and correct misunder-standings. Ideas are discussed while reading and problem solving together.

SAMPLE PROBLEM 1.3 A Study Plan for Learning Chemistry

Which of the following activities would you include in your study plan for learning chemistry successfully?

a. skipping lectureb. forming a study groupc. keeping a problem notebookd. waiting to study until the night before the exame. becoming an active learner

SOLUTIONYour success in chemistry can be improved by

b. forming a study groupc. keeping a problem notebooke. becoming an active learner

STUDY CHECK 1.3Which of the following will help you learn chemistry?

a. skipping review sessionsb. working assigned problemsc. attending the professor’s office hoursd. staying up all night before an exame. reading the assignment before a lecture

Students discuss a chemistry problem with their professor during office hours.

1.3 Learning Chemistry: A Study Plan

L E A R N I N G G O A L : Develop a study plan for learning chemistry.1.13 What are four things you can do to help yourself to succeed

in chemistry?

1.14 What are four things that would make it difficult for you to learn chemistry?

1.15 A student in your class asks you for advice on learning chemistry. Which of the following might you suggest?a. Form a study group.b. Skip a lecture.

c. Visit the professor during office hours.d. Wait until the night before an exam to study.e. Become an active learner.

1.16 A student in your class asks you for advice on learning chemistry. Which of the following might you suggest?a. Do the assigned problems.b. Don’t read the text; it’s never on the test.c. Attend review sessions.d. Read the assignment before a lecture.e. Keep a problem notebook.


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1.4 Learning Chemistry: Key Math SkillsDuring your study of chemistry, you will work many problems that involve numbers. You will need various math skills and operations. We will review some of the key math skills that are particularly important for chemistry. As we move through the chapters, we will also reference the key math skills as they apply.

A. Identifying Place ValuesFor any number, we can identify the place value for each of the digits in that number. These place values have names such as the ones place 1first place to the left of the decimal point2 or the tens place 1second place to the left of the decimal point2. Let’s look first at the place values for a number without a decimal point.

2518

Digit Place Value

2 thousands

5 hundreds

1 tens

8 ones

Now we look at a number that has a decimal point. We identify place values such as the tenths place 1first place to the right of the decimal point2 and hundredths place 1sec-ond place to the right of the decimal place2.

6.407

Digit Place Value

6 ones

4 tenths

0 hundredths

7 thousandths

Note that place values ending with the suffix ths refer to the decimal places to the right of the decimal point.

L E A R N I N G G O A LReview math concepts used in chemistry: place values, positive and negative numbers, percentages, solving equations, and interpreting line graphs.

KEY MATH SKILLIdentifying Place Values

CONCEPT CHECK 1.4 Place Values

Identify the place value for each of the digits in the number 825.10.

Digit Place Value

8

2

5

1

0

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1.4 LEARNING CHEMISTRY: KEY MATH SKILLS 13

B. Using Positive and Negative Numbers in CalculationsA positive number is any number that is greater than zero and has a positive sign 1+ 2. Often the positive sign is understood and not written in front of the number. For example, the number +8 can also be written as 8. A negative number is any number that is less than zero and is written with a negative sign 1- 2. For example, a negative eight is written as -8.

Multiplication and Division of Positive and Negative NumbersWhen two positive numbers or two negative numbers are multiplied, the answer is positive 1+ 2.

2 * 3 = +61-22 * 1-32 = +6

When a positive number and a negative number are multiplied, the answer is negative 1- 2.

2 * 1-32 = -61-22 * 3 = -6

The rules for the division of positive and negative numbers are the same as the rules for multiplication. When two positive numbers or two negative numbers are divided, the answer is positive 1+ 2.

63

= 2 -6-3

= 2

When a positive number and a negative number are divided, the answer is negative 1- 2.

-63

= -2 6

-3= -2

Addition of Positive and Negative NumbersWhen positive numbers are added, the sign of the answer is positive.

3 + 4 = 7 The + sign 1+72 is understood.

When negative numbers are added, the sign of the answer is negative.1-32 + 1-42 = -7

When a positive number and a negative number are added, the smaller number is subtracted from the larger number, and the result has the same sign as the larger number.

12 + 1-152 = -3

Subtraction of Positive and Negative NumbersWhen two numbers are subtracted, change the sign of the number to be subtracted.

12 - 1 !5 2 = 12 " 5 = 712 - 1 "5 2 = 12 ! 5 = 17-12 - 1 "5 2 = -12 ! 5 = -7-12 - 1 !5 2 = -12 " 5 = -17

KEY MATH SKILLUsing Positive and Negative Numbers in Calculations

ANSWER

Digit Place Value

8 hundreds

2 tens

5 ones

1 tenths

0 hundredths

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C. Calculating a Percentage To determine a percent, divide the parts by the total 1whole2 and multiply by 100%. For example, if there are 8 chemistry books on a shelf that has a total of 32 books, what is the percent of chemistry books?

8 chemistry books32 total books

* 100% = 25% chemistry books

When a value is described as a percent 1%2, it represents the number of parts of an item in 100 of those items. If the percent of red balls is 5%, it means there are 5 red balls in every 100 balls. If the percent of blue balls is 50%, there are 50 blue balls in every 100 balls.

5% red balls =5 red balls 100 balls

50% blue balls =50 blue balls

100 balls

CONCEPT CHECK 1.5 Percentage

If you eat 3 pieces 1parts2 of a pizza that contained 6 pieces 1whole2, what percent of the pizza did you eat?

ANSWER

We can calculate the percentage as

3 pieces of pizza6 pieces of pizza

* 100% = 50%

If you eat 3 pieces 1parts2 of a pizza that contained 6 pieces 1whole2, you ate 50% of that pizza.

KEY MATH SKILLCalculating a Percentage

Percentages as DecimalsIf you are given a percent such as 25%, it can be converted to a decimal.

1. Write the percent value over 100. 25100

2. Express the fraction as a decimal number. 0.25

D. Solving EquationsIn chemistry, we use equations that express the relationship between certain variables. Let’s look at how we would solve for x in the following equation:

2x + 8 = 14

Our overall goal is to rearrange the items in the equation to obtain x on one side.

1. Place all like terms on one side. The numbers 8 and 14 are like terms. To remove the 8 from the left side of the equation, we subtract 8. To keep a balance, we need to subtract 8 from the 14 on the other side.

2x + 8 - 8 = 14 - 82x = 6

2. Isolate the variable you need to solve for. In this problem, we obtain x by dividing both sides of the equation by 2. The value of x is the result when 6 is divided by 2.

2x2

=62

x = 3

KEY MATH SKILLSolving Equations

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3. Check your answer. Check your answer by substituting your value for x back into the original equation.

2132 + 8 = 6 + 8 = 14 Your answer x = 3 is correct.

Summary: To solve an equation for a particular variable, be sure you perform the same mathematical operations on both sides of the equation.

If you eliminate a symbol or number by subtracting, you need to subtract that same symbol or number on the opposite side.

If you eliminate a symbol or number by adding, you need to add that same symbol or number on the opposite side.

If you cancel a symbol or number by dividing, you need to divide both sides by that same symbol or number.

If you cancel a symbol or number by multiplying, you need to multiply both sides by that same symbol or number.

When we work with temperature, we may need to convert between degrees Celsius and degrees Fahrenheit using the following equation:

TF = 1.8TC + 32

To obtain the equation for converting degrees Fahrenheit to degrees Celsius, we subtract 32 from both sides.

TF = 1.8TC + 32 TF - 32 = 1.8TC + 32 - 32 TF - 32 = 1.8TC

To obtain TC by itself, we divide both sides by 1.8.

TF - 321.8

=1.8TC

1.8= TC

Temperatures are measured in degrees Fahrenheit and Celsius.

CONCEPT CHECK 1.6 Solving Equations

Solve each of the following equations for the specified variable:

a. P1V1 = P2V2; solve for V2b. q = m * !T * SH; solve for m

ANSWERa. P1V1 = P2V2

To solve for V2, divide both sides by the symbol P2.P1V1

P2=

P2V2

P2

V2 =P1V1

P2

b. q = m * !T * SH

To solve for m, divide both sides by the symbols !T and SH.q

!T * SH=

m * !T * SH!T * SH

m =q

!T * SH

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E. Interpreting a Line GraphA line graph represents the relationship between two variables. These quantities are plotted along two perpendicular axes, which are the x axis 1horizontal2 and y axis 1vertical2.ExampleIn the following graph, the volume of a gas in a balloon is plotted against its temperature.

TitleLook at the title. What does it tell us about the graph? The title indicates that the volume of a balloon was measured at different temperatures.

Vertical AxisLook at the label and the numbers on the vertical 1y2 axis. The label indicates that the vol-ume of the balloon was measured in liters. The numbers, which are chosen to include the low and high measurements of the volume of the gas, are evenly spaced from 22.0 L to 30.0 L.

Horizontal AxisThe label on the horizontal 1x2 axis indicates that the temperature of the balloon was mea-sured in degrees Celsius 1!C2. The numbers are measurements of the Celsius temperature, which are evenly spaced from 0. !C to 100. !C.

Points on the GraphEach point on the graph represents a volume in liters that was measured at a specific tem-perature. When these points are connected, a straight line is obtained.

Interpreting the Line GraphFrom the line graph, we see that the volume of the gas increases as the temperature of the gas increases. This is called a direct relationship. Now we use the line graph to determine the volume at various temperatures. For example, suppose we want to know the volume of the gas at 50. !C. We would start by finding 50. !C on the x axis and then drawing a line up to the line graph. From there, we would draw a horizontal line that intersects the y axis and read the volume value where the line crosses the y axis.

22.00. 20. 40. 60. 80. 100.

24.0

26.0

Vol

ume 1L2 28.0

30.0

Temperature 1°C2

Volume of a Balloon versus Temperature

y axis1vertical axis2

x axis 1horizontal axis2A line graph shows the relationship between two variables.

KEY MATH SKILLInterpreting a Line Graph

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CONCEPT CHECK 1.7 Interpreting a Line Graph

In this line graph, the distance traveled by a bicycle rider was measured for 10 h.

a. What is measured on the vertical axis?b. What is the range of values on the vertical axis?c. What is measured on the horizontal axis?d. What is the range of values on the horizontal axis?e. Does the distance increase or decrease with an increase in time?f. What distance, in kilometers, did the bicycle rider cover in 6 h?g. How many hours did the bicycle rider need to cover a distance of 15 km?

ANSWERa. distance, in kilometers b. 0 km to 50 kmc. time, in hours d. 0 h to 10 he. increase f. 30 kmg. 3 h

0 1 2 3 4 5 6 7 8 9 10

10

0

20

30

40

50

Time 1h2

Distance Covered by Bicycle Rider with TimeD

ista

nce 1km2


1.4 Learning Chemistry: Key Math Skills

L E A R N I N G G O A L : Review math concepts used in chemistry: place values, positive and negative numbers, percentages, solving equations, and interpreting line graphs.1.17 What is the place value for the bold digit? a. 7.3288

b. 16.1234c. 4675.99

1.18 What is the place value for the bold digit?a. 97.5689b. 375.88c. 46.1000

1.19 Solve each of the following:a. 15 - 1-82 = ________b. -8 + 1-222 = ________c. 4 * 1-22 + 6 = ________

1.20 Solve each of the following:a. -11 - 1-92 = ________b. 34 + 1-552 = ________

c. -56

8= ________

1.21 a. A test has 25 questions. If a student has 21 answers correct, what percent of the questions was correct? Express your answer to the ones place.

b. An alloy contains 56 g of pure silver and 22 g of pure copper. What is the percent silver in the alloy? Express your answer to the ones place.

c. A collection of coins contains 11 nickels, 5 quarters, and 7 dimes. What is the percent of dimes in the collection? Express your answer to the ones place.

1.22 a. A test has 35 questions. If a student has 29 answers correct, what percent was correct? Express your answer to the ones place.

b. An alloy contains 67 g of pure gold and 35 g of pure zinc. What is the percent zinc in the alloy? Express your answer to the ones place.

c. A collection of coins contains 15 pennies, 14 dimes, and 6 quarters. What is the percent of pennies in the collection? Express your answer to the ones place.

1.23 Solve each of the following for a:a. 4a + 4 = 40

b. a6

= 7

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Use the following line graph for Questions 1.25 and 1.26:

Tem

pera

ture

1°C2

200 20 40

Time 1min2

Time for Cooling of Tea versus Temperature

60 80 100

30

40

50

60

70

80

1.24 Solve each of the following for b:a. 2b + 7 = b + 10 b. 3b - 4 = 24 - b

1.25 a. What does the title indicate about the graph?b. What is measured on the vertical axis?c. What is the range of values on the vertical axis?d. Does the temperature increase or decrease with an

increase in time?

1.26 a. What is measured on the horizontal axis?b. What is the range of values on the horizontal axis?c. What is the temperature of the tea after 20 min?d. How many minutes were needed to reach a temperature

of 45 !C?

1.1 Chemistry and ChemicalsL E A R N I N G G O A L : Define the term chemistry and identify substances as chemicals.• Chemistry is the study of the com-

position, structure, properties, and reactions of matter.

• A chemical is any substance that always has the same composition and properties wherever it is found.

1.2 Scientific Method: Thinking Like a ScientistL E A R N I N G G O A L : Describe the activities that are part of the scientific method.• The scientific method is a

process of explaining natural phenomena beginning with making observations, forming a hypothesis, and performing experiments.

• A theory may be proposed when repeated experimental results by many scientists support the hypothesis.

1.3 Learning Chemistry: A Study PlanL E A R N I N G G O A L : Develop a study plan for learning chemistry.• A study plan for learning chemistry

utilizes the features in the text and develops an active learning approach to study.

• By using the Learning Goals in the chapter and working the Concept Checks, Sample Problems, Study Checks, and the Questions and Problems at the end of each section, you can successfully learn the concepts of chemistry.

1.4 Learning Chemistry: Key Math SkillsL E A R N I N G G O A L : Review math concepts used in chemistry: place values, positive and negative numbers, percentages, solving equations, and interpreting line graphs.• Solving chemistry problems

involves a number of math skills: determining place values, using positive and negative numbers, using percentages, solving algebraic equations, and interpreting graphs.

CHAPTER REVIEW

KEY MATH SKILLS 19

CONCEPT MAP

Place Values

Positive andNegative Numbers

Percentages

Equations

Graphs

Substances

Chemicals

CHEMISTRY

uses key math skills

Reading the Text

Practicing Problem Solving

Self-testing

Working witha Group

is learned bydeals with

Scientific Method

Observations

Hypothesis

Experiments

Theory

uses the

starting with

that lead to

called

KEY TERMS

chemical A substance that has the same composition and properties wherever it is found.

chemistry The study of the composition, structure, properties, and reactions of matter.

experiment A procedure that tests the validity of a hypothesis.hypothesis An unverified explanation of a natural phenomenon.

observation Information determined by noting and recording a natural phenomenon.

scientific method The process of making observations, proposing a hypothesis, testing the hypothesis, and developing a theory that explains a natural event.

theory An explanation of an observation that has been validated by repeated experiments that support a hypothesis.

KEY MATH SKILLS�

The chapter section containing each Key Math Skill is shown in paren-theses at the end of each heading.

Identifying Place Values 11.4A2• The place value identifies the numerical value of each digit

in a number.

Example: Identify the place values for each of the digits in the number 456.78.

Answer:

Using Positive and Negative Numbers in Calculations 11.4B2• A positive number is any number that is greater than zero and has

a positive sign 1+ 2. A negative number is any number that is less than zero and is written with a negative sign 1- 2.

• When two positive numbers are added, multiplied, or divided, the answer is positive.

• When two negative numbers are multiplied or divided, the answer is positive.

• When a positive and a negative number are multiplied or divided, the answer is negative.

• When a positive and a negative number are added, the smaller number is subtracted from the larger number and the result has the same sign as the larger number.

• When two numbers are subtracted, change the sign of the number to be subtracted.

Digit Place Value

4 hundreds5 tens6 ones7 tenths8 hundredths

20 CHAPTER 1 CHEMISTRY IN OUR LIVES20 CHAPTER 1 CHEMISTRY IN OUR LIVES

UNDERSTANDING THE CONCEPTS

The chapter sections to review are shown in parentheses at the end of each question.

1.27 A “chemical-free” shampoo includes the following ingredients: water, cocomide, glycerin, and citric acid. Is the shampoo truly “chemical-free”? 11.12

1.28 A “chemical-free” sunscreen includes the following ingredi-ents: titanium dioxide, vitamin E, and vitamin C. Is the sunscreen truly “chemical-free”? 11.12

Example: Solve each of the following:a. -8 - 14 = ________b. 6 * 1-32 = ________

Answer: a. -8 - 14 = -22b. 6 * 1-32 = -18

Calculating a Percentage 11.4C2• A percentage is the part divided by the total 1whole2 multiplied

by 100%.

Example: A drawer contains 6 white socks and 18 black socks. What is the percent of white socks?

Answer: 6 white socks24 total socks

* 100% = 25% white socks

Solving Equations 11.4D2An equation in chemistry often contains an unknown. To rearrange an equation to obtain the unknown factor by itself, you keep it balanced by performing matching mathematical operations on both sides of the equation.

• If you eliminate a number or symbol by subtracting, subtract that same number or symbol on the opposite side.

• If you eliminate a number or symbol by adding, add that same number or symbol on the opposite side.

• If you cancel a number or symbol by dividing, divide both sides by that same number or symbol.

• If you cancel a number or symbol by multiplying, multiply both sides by that same number or symbol.

Example: Solve the equation for a: 3a - 8 = 28

Answer: Add 8 to both sides 3a - 8 + 8 = 28 + 8

3a = 36

Divide both sides by 3 3a3

=363

a = 12

Interpreting a Line Graph 11.4E2A line graph represents the relationship between two variables. These quantities are plotted along two perpendicular axes, which are the x axis 1horizontal2 and y axis 1vertical2. The title indi-cates the components of the x and y axes. Numbers on the x and y axes show the range of values of the variables. The line graph shows the relationship between the component on the y axis and that on the x axis.

Example:

500

450

400

350

300

250

200

150

100

0 20 40 60 80 100

Solu

bilit

y 1g of su

gar/

100

mL

wat

er2

Temperature 1°C2

Solubility of Sugar in Water

a. Does the amount of sugar that dissolves in 100 mL of water increase or decrease when the temperature increases?

b. How many grams of sugar dissolve in 100 mL of water at 70 !C?

c. At what temperature 1!C2 will 275 g of sugar dissolve in 100 mL of water?

Answer: a. increase b. 320 g c. 55 !C

1.29 According to Sherlock Holmes, “One must follow the rules of scientific inquiry, gathering, observing, and testing data, then formulating, modifying, and rejecting hypotheses, until only one remains.” Did Sher-lock use the scientific method? Why or why not? 11.22

Sherlock Holmes is a fictional detective in novels written by Arthur Conan Doyle.

ADDITIONAL QUESTIONS AND PROBLEMS 21

Aluminum melts at 660 °C.

1.32 Classify each of the following statements as an observation 1O2 or a hypothesis 1H2: 11.22a. Analysis of 10 ceramic dishes showed that four dishes

contained lead levels that exceeded federal safety standards.

b. Marble statues undergo corrosion in acid rain.c. Statues corrode in acid rain because the acidity is suffi-

cient to dissolve calcium carbonate, the major substance of marble.

1.33 For each of the following, indicate if the answer has a positive or negative sign: 11.42a. Two negative numbers are added.b. A positive and negative number are multiplied.

1.34 For each of the following, indicate if the answer has a positive or negative sign: 11.42a. A negative number is subtracted from a positive

number.b. Two negative numbers are divided.

1.30 In A Scandal in Bohemia, Sherlock Holmes receives a mysteri-ous note. He states, “I have no data yet. It is a capital mistake to theorize before one has data. Insensibly one begins to twist facts to suit theories, instead of theories to suit facts.” What do you think Sherlock meant? 11.22

1.31 Classify each of the following statements as an observation 1O2 or a hypothesis 1H2: 11.22a. Aluminum melts at 660 !C.b. Dinosaurs became extinct when a large meteorite struck

Earth and caused a huge dust cloud that severely decreased the amount of light reaching Earth.

c. The 100-yard dash was run in 9.8 seconds.

1.35 Why does the scientific method include a hypothesis? 11.221.36 Why is experimentation an important part of the scientific

method? 11.221.37 Select the correct phrase1s2 to complete the following state-

ment: If experimental results do not support your hypothesis, you should 11.22a. pretend that the experimental results support your hypothesis.b. write another hypothesis.c. do more experiments.

1.38 Select the correct phrase1s2 to complete the following state-ment: A hypothesis becomes a theory when 11.22a. one experiment proves the hypothesis.b. many experiments by many scientists validate the hypothesis.c. you decide to call it a theory.

1.39 Which of the following will help you develop a successful study plan? 11.32a. Skip lecture and just read the text.b. Work the Sample Problems as you go through a chapter.c. Go to your professor’s office hours.d. Read through the chapter, but work the problems later.

1.40 Which of the following will help you develop a successful study plan? 11.32a. Study all night before the exam.b. Form a study group and discuss the problems together.

c. Work problems in a notebook for easy reference.

d. Copy the answers to homework from a friend.

1.41 Solve each of the following: 11.42a. 4 * 1-82 = ________b. -12 - 48 = ________

c. -168

-4= ________

1.42 Solve each of the following: 11.42a. -95 - 1-112 = ________

b. 152-19

= ________

c. 4 - 56 = ________

1.43 A bag of gumdrops contains 16 orange gumdrops, 8 yellow gumdrops, and 16 black gumdrops. 11.42a. What is the percent of yellow gumdrops?b. What is the percent of black gumdrops?

1.44 On the first chemistry test, 12 students got As, 18 students got Bs, and 20 students got Cs. 11.42a. What is the percent of students who received Bs? Express

your answer to the ones place.b. What is the percent of students who received Cs? Express

your answer to the ones place.

ADDITIONAL QUESTIONS AND PROBLEMS


ANSWERS

Answers to Study Checks

1.1 a, b, and d

1.2 a. experiment 1E2 b. observation 1O2

c. hypothesis 1H2 1.3 b, c, and e

Answers to Selected Questions and Problems

1.1 a. Chemistry is the study of the composition, structure, prop-erties, and reactions of matter.

b. A chemical is a substance that has the same composition and properties wherever it is found.

1.3 Many chemicals are listed on a vitamin bottle such as vitamin A, vitamin B3, vitamin B12, vitamin C, and folic acid.

1.5 Typical items found in a medicine cabinet and some of the chemicals they contain are as follows:

Antacid tablets: calcium carbonate, cellulose, starch, stearic acid, silicon dioxide

Mouthwash: water, alcohol, thymol, glycerol, sodium benzoate, benzoic acid

Cough suppressant: menthol, beta-carotene, sucrose, glucose

1.7 An advantage of a pesticide is that it gets rid of insects that bite or damage crops. A disadvantage is that a pesticide can destroy beneficial insects or be retained in a crop that is eventually eaten by animals or humans.

1.9 a. A hypothesis proposes a possible explanation for a natural phenomenon.

b. An experiment is a procedure that tests the validity of a hypothesis.

c. A theory is a hypothesis that has been validated many times by many scientists.

d. An observation is a description or measurement of a natural phenomenon.

1.11 a. observation 1O2 b. hypothesis 1H2c. experiment 1E2 d. observation 1O2e. observation 1O2 f. theory 1T2

1.13 There are several things you can do that will help you suc-cessfully learn chemistry, including forming a study group, going to lecture, working Sample Problems and Study Checks, working Questions and Problems and checking answers, read-ing the assignment ahead of class, and keeping a problem notebook.

1.15 a, c, and e

1.17 a. thousandths b. ones c. hundreds

CHALLENGE QUESTIONS

Use the following graph for Problems 1.49 and 1.50:

0.350.300.250.20

Solu

bilit

y 1g CO 2

/100

g w

ater2

0.150.100.05

00 10 20

Temperature 1°C2

Solubility of Carbon Dioxide in Water

30 40 50 60

1.49 a. What does the title indicate about the graph? 11.42b. What is measured on the vertical axis?c. What is the range of values on the vertical axis?d. Does the solubility of carbon dioxide increase or decrease

with an increase in temperature?

1.50 a. What is measured on the horizontal axis? 11.42b. What is the range of values on the horizontal axis?c. What is the solubility of carbon dioxide in water at 25 !C?d. At what temperature does carbon dioxide have a solubility

of 0.2 g/100 g water?

The following groups of questions are related to the topics in this chapter. However, they do not all follow the chapter order, and they require you to combine concepts and skills from several sections. These questions will help you increase your critical thinking skills and prepare for your next exam.

1.45 Classify each of the following as an observation 1O2, a hypoth-esis 1H2, or an experiment 1E2: 11.22a. The bicycle tire is flat.b. If I add air to the bicycle tire, it will expand to the proper size.c. When I added air to the bicycle tire, it was still flat.d. The bicycle tire must have a leak in it.

1.46 Classify each of the following as an observation 1O2, a hypoth-esis 1H2, or an experiment 1E2: 11.22a. A big log in the fire does not burn well.b. If I chop the log into smaller wood pieces, it will burn better.c. The small wood pieces burn brighter and make a hotter fire.d. The small wood pieces are used up faster than burning

the big log.

1.47 Solve each of the following for x: 11.42a. 2x + 5 = 41

b. 5x3

= 40

1.48 Solve each of the following for z: 11.42a. 3z - 1-62 = 12

b. 4z

-12= -8

ANSWERS 23

1.19 a. 23 b. -30 c. -2

1.21 a. 84% b. 72% c. 30%

1.23 a. 9 b. 42

1.25 a. The graph shows the relationship between the temperature of a cup of tea and time.

b. temperature, in !Cc. 20 !C to 80 !Cd. decrease

1.27 No. All of the ingredients are chemicals.

1.29 Yes. Sherlock’s investigation includes making observa-tions 1gathering data2, formulating a hypothesis, testing the hypothesis, and modifying it until one of the hypotheses is validated.

1.31 a. observation 1O2 b. hypothesis 1H2c. observation 1O2

1.33 a. negative b. negative

1.35 A hypothesis, which is a possible explanation for an observation, can be tested with experiments.

1.37 b and c

1.39 b and c

1.41 a. -32 b. -60 c. 42

1.43 a. 20% b. 40%

1.45 a. observation 1O2 b. hypothesis 1H2 c. experiment 1E2 d. hypothesis 1H2 1.47 a. 18 b. 24

1.49 a. The graph shows the relationship between the solubility of carbon dioxide in water and temperature.

b. solubility of carbon dioxide 1g CO2/100 g water2c. 0 to 0.35 g of CO2/100 g of waterd. decrease

During the past few months, Greg has been experiencing an increased number of headaches, and frequently feels dizzy and nauseous. He goes to his doctor’s office where the registered nurse completes the initial part of the exam by recording several measurements: weight 88.5 kg, height 190.5 cm, temperature 37.2 °C, and blood pressure at 155/95. A normal blood pressure is 120/80 or below.

When Greg sees his doctor, he is diagnosed as having high blood pressure 1hypertension2. The doctor prescribes 80 mg of Inderal 1propranolol2, which is used to treat hypertension and is to be taken once a day. The registered nurse fills the prescription at the pharmacy.

Two weeks later, Greg visits his doctor again, who determines that his blood pressure is now 152/90. The doctor increases the dosage of Inderal to 160 mg, once

daily. The registered nurse informs Greg that he needs to increase his daily dosage to 2 tablets.

Career: Registered NurseIn addition to assisting physicians, registered nurses work to promote patient health, and prevent and treat disease. They provide patient care and help patients cope with illness. They take measurements such as a patient’s weight, height, temperature, and blood pres-sure; make conversions; and calculate drug dosage rates. Registered nurses also maintain detailed medical records of patient symptoms, prescribed medications, and any reactions.

24

2 MeasurementsL O O K I N G A H E A D2.1 Units of Measurement2.2 Scientific Notation2.3 Measured Numbers and

Significant Figures2.4 Significant Figures in Calculations2.5 Prefixes and Equalities2.6 Writing Conversion Factors2.7 Problem Solving Using Unit

Conversion2.8 Density

2.1 UNITS OF MEASUREMENT 25

Chemistry and measurements are an important part of our everyday lives. Levels of toxic materials in the air, soil, and water are discussed in our newspapers. We read about radon gas in our homes, holes in the ozone layer, trans fatty acids, and

climate change. Understanding chemistry and measurement helps us make proper choices about our world.

Think about your day. You probably took some measurements. Perhaps you checked your weight by stepping on a bathroom scale. If you made some rice for dinner, you added 2 cups of water to 1 cup of rice. If you did not feel well, you may have taken your temperature. Whenever you take a measurement, you use a measuring device such as a balance, a measuring cup, or a thermometer. Over the years, you have learned to read the markings on each device to take a correct measurement.

Scientists measure the amounts of the materials that make up everything in our universe. An engineer determines the amount of metal in an alloy or the vol-ume of seawater flowing through a desalination plant. A physician orders labora-tory tests to measure substances in the blood such as glucose or cholesterol. An environmental chemist measures the levels of pollutants such as lead and carbon monoxide in our soil and atmosphere.

By learning about measurement, you develop skills for solving problems and how to work with numbers in chemistry. An understanding of measurement is essential to evaluate our health and surroundings.

Your weight on a bathroom scale is a measurement.

2.1 Units of MeasurementSuppose you walked 1.3 mi to campus today carrying a backpack that weighs 26 lb. The temperature was 72 °F. Perhaps you weigh 128 lb and your height is 65 in. These mea-surements and units may seem familiar to you because they are stated in the U.S. system of measurement. However, in chemistry, we use the metric system in making our measurements. Using the metric system, you walked 2.1 km to campus carrying a backpack that has a mass of 12 kg, when the temperature was 22 °C. You have a mass of 58.2 kg and a height of 165 cm.

Scientists throughout the world use the metric system of measurement. The International System of Units 1SI2 or Système International is the official system of measurement throughout the world except for the United States. In chemistry, we use metric and SI units for length, volume, mass, temperature, and time 1see Table 2.12.

165 cm165 in.222 °C172 °F2 58.2 kg1128 lb212 kg126 lb2 2.1 km11.3 mi2

L E A R N I N G G O A LWrite the names and abbreviations for the metric or SI units used in measurements of length, volume, mass, temperature, and time.

CHAPTER READINESS*

Key Math Skills

◆ Identifying Place Values (1.4A)

*This Key Math Skill from the previous chapter is listed here for your review as you proceed to the new material in this chapter.

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26 CHAPTER 2 MEASUREMENTS

TABLE 2.1 Units of Measurement and Their Abbreviations

Measurement Metric SI

Length meter 1m2 meter 1m2Volume liter 1L2 cubic meter 1m32Mass gram 1g2 kilogram 1kg2Temperature degree Celsius 1!C2 kelvin 1K2Time second 1s2 second 1s2

Chemists working in research laboratories test new products and develop new pharmaceuticals.

LengthThe metric and SI unit of length is the meter 1m2. A meter is 39.37 in., which makes it slightly longer than a yard 11.094 yd2. The centimeter 1cm2, a smaller unit of length, is commonly used in chemistry and is about equal to the width of your little finger. For com-parison, there are 2.54 cm in 1 in. 1see Figure 2.12. Some useful relationships between different units for length follow:

1 m = 1.094 yd 1 m = 39.37 in. 1 m = 100 cm

2.54 cm = 1 in.

FIGURE 2.1 Length in the metric 1SI2 system is based on the meter, which is slightly longer than a yard.Q How many centimeters are in

a length of 1 inch?

Centimeters1 2 3 4 5

1

10 20 30 40 50 60 70 80 90 100

12 36

1 ft 2 ft 3 ft

Meterstick

Yardstick

Inches24

1 in. = 2.54 cm1 m = 39.37 in.

VolumeVolume 1V 2 is the amount of space a substance occupies. The SI unit of volume, the cubic meter 1m32 is the volume of a cube that has sides that measure 1 m in length. In a labora-tory or a hospital, the cubic meter is too large for practical use. Instead, chemists work with metric units of volume that are smaller and more convenient, such as the liter 1L2 and milliliter 1mL2. The volume of 1 mL is the same as 1 cm3. A liter is slightly larger than a quart 11 L = 1.057 qt2 and contains 1000 mL, as shown in Figure 2.2. A cubic meter is the same volume as 1000 L. Some useful relationships between different units for volume follow:

1 m3 = 1000 L 1 L = 1000 mL

1 mL = 1 cm3

1 L = 1.057 qt 946.3 mL = 1 qt

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2.1 UNITS OF MEASUREMENT 27

MassThe mass of an object is a measure of the quantity of material it contains. The SI unit of mass, the kilogram 1kg2, is used for larger masses, such as body mass. The standard for mass, the international prototype kilogram 1IPK2, is a cylinder that is made of a platinum–iridium alloy. In the metric system, the unit for mass is the gram 1g2, which is used for smaller masses. There are 1000 g in one kilogram. In comparison to the U.S. system, the mass of 1 kg is equivalent to 2.205 lb, and 453.6 g is equal to one pound. Some useful relationships between different units for mass follow:

1 kg = 1000 g 1 kg = 2.205 lb

453.6 g = 1 lb

You may be more familiar with the term weight than with the word mass. Weight is a measure of the gravitational pull on an object. On Earth, an astronaut with a mass of 75.0 kg has a weight of 165 lb. On the Moon, where the gravitational pull is one-sixth that of Earth, the astronaut would weigh 27.5 lb. However, the mass of the astronaut, 75.0 kg, is the same on the Moon as on Earth. Scientists measure mass rather than weight because mass does not depend on gravity.

In a chemistry laboratory, an electronic balance is used to measure the mass of a sub-stance in grams 1see Figure 2.32.

TemperatureTemperature tells us how hot something is, and how cold it is outside, or it helps us determine if we have a fever. In the metric system, temperature is measured in degrees Celsius. On the Celsius 1 !C2 temperature scale, water freezes at 0 °C and boils at 100 °C, while on the Fahrenheit 1°F2 scale, water freezes at 32 °F and boils at 212 °F 1see Figure 2.42. In the SI system, temperature is measured using the Kelvin 1K2 tempera-ture scale, on which the lowest temperature is 0 K. A unit on the Kelvin scale is called a kelvin 1K2 and is not written with a degree sign.

1000 mL = 1 L = 1.057 qt

FIGURE 2.2 Volume is the space occupied by a substance. In the metric system, volume is based on the liter, which is slightly larger than a quart.Q How many quarts are in 1 L?

The standard kilogram for the United States is stored at the National Institute of Standards and Technology 1NIST2.

FIGURE 2.3 On an electronic bal-ance, the digital readout gives the mass of a nickel, which is 5.01 g.Q What would be the mass of

10 nickels?

FIGURE 2.4 A thermometer is used to determine temperature.Q What kinds of temperature

readings have you made today?

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A stopwatch is used to measure the time of a race.

2.2 Scientific NotationIn chemistry, we use numbers that are very large and very small. We might measure something as tiny as the width of a human hair, which is about 0.000 008 m. Or per-haps we want to count the number of hairs on the average human scalp, which is about 100 000 hairs 1see Figure 2.52. In this text, we add spaces between sets of three digits when it helps make the places easier to count. However, we will see that it is more conve-nient to write large and small numbers in scientific notation.

Item Standard Number Scientific Notation

Width of a human hair 0.000 008 m 8 * 10-6 m

Hairs on a human scalp 100 000 hairs 1 * 105 hairs

TimeThe SI and metric unit of time is the second 1s2. However, we also measure time in units such as years 1y2, days, hours 1h2, or minutes 1min2. The standard device now used to determine a second is an atomic clock. Some useful relationships between different units for time follow:

1 day = 24 h 1 h = 60 min

1 min = 60 s

CONCEPT CHECK 2.1 Units of Measurement

State the type of measurement indicated in each of the following:

a. 45.6 g b. 1.85 m3

c. 14 cm d. 45 °C

ANSWERa. A gram is a unit of mass.b. A cubic meter is a unit of volume.c. A centimeter is a unit of length.d. A degree Celsius is a unit of temperature.

L E A R N I N G G O A LWrite a number in scientific notation.

2.1 Units of Measurement�

L E A R N I N G G O A L : Write the names and abbreviations for the metric or SI units used in measurements of length, volume, mass, temperature, and time.2.1 State the name of the unit and the type of measurement for

each of the following:a. 4.8 m b. 325 g c. 1.5 Ld. 480 s e. 28 °C

2.2 State the name of the unit and the type of measurement for each of the following:a. 85 mL b. 36 cm c. 14 kgd. 35 g e. 373 K

2.3 State the name of the unit in each of the following, and iden-tify that unit as a metric/SI unit or not:a. 5.5 mL b. 45 kg c. 16 in.d. 25 s e. 22 °C

2.4 State the name of the unit in each of the following, and iden-tify that unit as a metric/SI unit or not:a. 8 m3 b. 245 K c. 45 °Fd. 125 L e. 125 g

2.5 Give the abbreviation for each of the following:a. gram b. literc. degree Celsius d. pounde. second

2.6 Give the abbreviation for each of the following:a. kilogram b. kelvinc. quart d. metere. cubic meter


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2.2 SCIENTIFIC NOTATION 29

FIGURE 2.5 Humans have an average of 1 * 105 hairs on their scalps. Each hair is about 8 * 10-6 m wide.Q Why are large and small

numbers written in scientific notation?

8 * 10-6 m1 * 105 hairs

Writing a Number in Scientific NotationA number written in scientific notation consists of three parts: a coefficient, a power of 10, and a unit of measurement. For example, 2400 m is written in scientific notation as 2.4 * 103 m. The coefficient is 2.4, and the value 103 shows the power of 10 is 3, while the unit is meter 1m2. The coefficient was obtained by moving the decimal point to the left to give a number that was at least 1 but less than 10. Because we moved the decimal point three places to the left, the power of 10 is a positive 3, which is written as 103. When a number greater than 1 is converted to scientific notation, the power of 10 is positive.

2 4 0 0. m = 2.4 * 103 m 3 places Coefficient Power

of tenUnit

When a number less than 1 is written in scientific notation, the power of 10 is a negative number. For example, the number 0.000 86 g is written in scientific nota-tion by moving the decimal point to give a coefficient of 8.6. Because the decimal point was moved four places to the right, the power of 10 becomes a negative 4, written as 10-4.

0.0 0 0 8 6 g = 8.6 10-4 g4 places Coefficient Power

of tenUnit

*

Table 2.2 gives examples of numbers written as positive and negative powers of 10. The powers of 10 are a way of keeping track of the decimal point in the deci-mal number. Table 2.3 gives several examples of writing measurements in scientific notation.

KEY MATH SKILLUsing Scientific Notation

TABLE 2.2 Some Powers of 10

Number Multiples of 10 Scientific Notation

1000 10 * 10 * 10 1 * 103

100 10 * 10 1 * 102Some positive

10 10 1 * 101 powers of 10

1 0 1 * 100

0.1 110

1 * 10-1

0.01 110

* 110

=1

1001 * 10-2 Some negative

powers of 10

0.001 110

* 110

* 110

=1

10001 * 10-3

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SAMPLE PROBLEM 2.1 Scientific Notation�

Write each of the following in scientific notation:

a. 3500 g b. 0.000 016 L

SOLUTIONa. 3500 g

Step 1 Move the decimal point to obtain a coefficient that is at least 1 but less than 10. For a number greater than 1, the decimal point is moved to the left three places to give a coefficient of 3.5.

Scientific Notation and CalculatorsYou can enter a number written in scientific notation on many calculators using the EE or EXP key. After you enter the coefficient, press the EXP 1or EE2 key and enter the power 1exponent2, because the EXP function key already includes the *10 value. To enter a negative power, you press the plus/minus 1+ /-2 key or the minus 1- 2 key, depending on your calculator. As you work through these problems, read the instruction manual for your particular calculator to determine the proper sequence for using keys.

Number to Enter Method Calculator Display

4 * 106 4 EXP 1EE2 6 4 0 6 or 4 06 or 4 E06

2.5 * 10-4 2.5 EXP 1EE2 + /- 4 2.5! 04 or 2.5!04 or 2.5 E! 04

When a calculator display appears in scientific notation, it is shown as a number that is more than 1 but less than 10, followed by a space and the power 1exponent2. To express this in scientific notation, write the coefficient, followed by *10, and an exponent as the power of 10.

Calculator Display Expressed in Scientific Notation

7.52 04 or 7.52 04 or 7.52 E04 7.52 * 104

5.8! 02 or 5.8 !02 or 5.8 E! 02 5.8 * 10-2

On many scientific calculators, a number is converted into scientific notation using the appropriate keys. For example, the number 0.000 52 is entered, followed by pressing the 2nd or 3rd function key and the SCI key. The scientific notation appears in the calcula-tor display as a coefficient and the power of 10.

-0.000 52 5.2 * 10-4

Key Key Calculator display

2nd or 3rd function key SCI oror ==

TABLE 2.3 Some Measurements Written in Scientific Notation

Measured Quantity Measurement Scientific Notation

Volume of gasoline used in the United States each year 550 000 000 000 L 5.5 * 1011 LDiameter of Earth 12 800 000 m 1.28 * 107 mTime for light to travel from the Sun to Earth 500 s 5 * 102 sMass of a typical human 68 kg 6.8 * 101 kgMass of a hummingbird 0.002 kg 2 * 10-3 kgDiameter of a chickenpox 1varicella zoster2 virus 0.000 000 3 m 3 * 10-7 mMass of bacterium 1mycoplasma2 0.000 000 000 000 000 000 1 kg 1 * 10-19 kg

A chickenpox virus has a diameter of 3 * 10-7 m.

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2.2 SCIENTIFIC NOTATION 31

Converting Scientific Notation to a Standard NumberWhen a number written in scientific notation has a positive power of 10, the standard num-ber is obtained by moving the decimal point to the right for the same number of places as the power of 10. Placeholder zeros are used, as needed, to give additional places.

4 . 3 * 102 L = 4.30 L = 430 L

For a number with a negative power of 10, the standard number is obtained by moving the decimal point to the left for the same number of places as the power of 10. Placeholder zeros are added in front of the coefficient as needed.

2 . 5 * 10-5 s = 0000025 s = 0.000 025 s

1Move the decimal point to obtain a coefficient that is at least 1 but less than 10.

2

3

Guide to Writing a Number inScientific Notation

Express the number of places moved as a power of 10.

Write the product of the coefficient multiplied by the power of 10 with the unit.

Step 2 Express the number of places moved as a power of 10. When the decimal point is moved to the left, the power of 10 is positive. Moving the decimal point three places to the left gives a power of 3, written as 103.

Step 3 Write the product of the coefficient multiplied by the power of 10 with the unit.

3.5 * 103 g

b. 0.000 016 L

Step 1 Move the decimal point to obtain a coefficient that is at least 1 but less than 10. For a number less than 1, the decimal point is moved to the right five places to give a coefficient of 1.6.

Step 2 Express the number of places moved as a power of 10. When the decimal point is moved to the right, the power of 10 is negative. Moving the decimal point five places to the right gives a power of negative 5, written as 10-5.

Step 3 Write the product of the coefficient multiplied by the power of 10 with the unit.

1.6 * 10-5 L

STUDY CHECK 2.1Write each of the following in scientific notation:

a. 425 000 mb. 0.000 000 8 g

SAMPLE PROBLEM 2.2 Writing Scientific Notation as a Standard Number

Write each of the following as a standard number:

a. 7.2 * 10-3 m b. 2.4 * 105 g

SOLUTIONa. To write the standard number for an exponential number with a negative power of 10,

move the decimal point to the left 1in front of 7.22 the same number of places 1three2 as the power of 10. Add placeholder zeros before the coefficient as needed.

7 . 2 * 10-3 m = 0007.2 m = 0.0072 m

b. To write the standard number for an exponential number with a positive power of 10, move the decimal point to the right 1after 2.42 the same number of places 1five2 as the power of 10. Add placeholder zeros following the coefficient as needed.

2 . 4 * 105 g = 2.40000 g = 240 000 g

STUDY CHECK 2.2Write 7.25 * 10-4 s as a standard number.

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FIGURE 2.6 The lengths of the rectangular objects are measured as 1a2 4.5 cm and 1b2 4.55 cm.Q What is the length of the

object in 1c2?

10cm

2 3 4 5

10cm

2 3 4 5

10cm

2 3 4 5

1a21b21c2

2.2 Scientific Notation�

L E A R N I N G G O A L : Write a number in scientific notation.2.7 Write each of the following in scientific notation:

a. 55 000 m b. 480 g c. 0.000 005 cmd. 0.000 14 s e. 0.007 85 L f. 670 000 kg

2.8 Write each of the following in scientific notation:a. 180 000 000 g b. 0.000 06 mc. 750 000 g d. 0.15 mLe. 0.024 s f. 1500 m3

2.9 In each of the following pairs, which number is larger?a. 7.2 * 103 cm or 4.2 * 103 cmb. 4.5 * 10-4 kg or 3.2 * 10-2 kgc. 1 * 104 L or 1 * 10-4 Ld. 0.000 52 m or 6.8 * 10-2 m

2.10 In each of the following pairs, which number is smaller?a. 4.9 * 10-3 s or 5.5 * 10-9 sb. 1500 kg or 3.4 * 102 kgc. 0.000 000 41 m or 5.0 * 102 md. 2.5 * 105 g or 4.0 * 105 g

2.11 Write each of the following as a standard number:a. 1.2 * 104 sb. 8.25 * 10-2 kgc. 4 * 106 gd. 5.8 * 10-3 m3

2.12 Write each of the following as a standard number:a. 3.6 * 10-5 Lb. 8.75 * 104 cmc. 3 * 10-2 mLd. 2.12 * 105 kg


2.3 Measured Numbers and Significant FiguresWhen you make a measurement, you use some type of measuring device. For example, you may use a meterstick to measure your height, a scale to check your weight, or a ther-mometer to take your temperature.

Measured NumbersMeasured numbers are the numbers you obtain when you measure a quantity using a measuring tool. Suppose you are going to measure the lengths of the objects in Figure 2.6. You would select a metric ruler that may have lines marked in 1-cm divisions or perhaps in divisions of 0.1 cm. To report the length of an object, you observe the numerical values of the marked lines at the end of the object. Finally, you estimate by visually dividing the space between the smallest marked lines. This estimated number is the final digit that is reported for a measured number.

For example, in Figure 2.6a, the end of the object is between the marks for 4 cm and 5 cm. Thus you know that its length is more than 4 cm but less than 5 cm. Now you could estimate that the end is halfway between 4 cm and 5 cm and report its length as 4.5 cm. However, another student might estimate the length of this object as 4.4 cm because people do not estimate the same way. Therefore, there is always some uncertainty about the estimated number in every measurement.

The metric ruler shown in Figure 2.6b is marked at every 0.1 cm. With this ruler, you can now estimate the value of the hundredths place 10.01 cm2. Now you could estimate that the length of the object is between 4.5 and 4.6 cm. Perhaps you report its length as 4.55 cm, while another student may report its length as 4.56 cm. Both results are acceptable.

In Figure 2.6c, the end of the object appears to line up with the 3-cm mark. Because the divisions are marked in units of 1 cm, the estimated digit in the tenths place 10.1 cm2 is 0. The reported measurement for length is reported as 3.0 cm, not 3. This means that the uncertainty of the measurement 1the last digit2 is in the tenths place 10.1 cm2. There is always uncertainty in every measurement.

Significant FiguresIn a measured number, the significant figures 1SFs2 are all the digits including the esti-mated digit. All nonzero numbers are counted as significant figures. However, a zero may or may not be significant, depending on its position in the number. Table 2.4 gives the rules and examples for counting significant figures.

L E A R N I N G G O A LIdentify a number as measured or exact; determine the number of significant figures in a mea-sured number.

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2.3 MEASURED NUMBERS AND SIGNIFICANT FIGURES 33

TABLE 2.4 Significant Figures in Measured Numbers

Rule

Measured Number

Number of Significant Figures

1. A number is a significant figure if it isa. not a zero 4.5 g 2

122.35 m 5b. one or more zeros between nonzero digits 205 m 3

5.008 kg 4c. one or more zeros at the end of a decimal

number50. L25.0 °C16.00 g

234

d. in the coefficient of a number written in scientific notation

4.8 * 105 kg5.70 * 10-3 m

23

2. A zero is not significant if it isa. at the beginning of a decimal number 0.0004 s 1

0.075 cm 2

b. used as a placeholder in a large number without a decimal point

850 000 m1 250 000 g

23

Scientific Notation and Significant ZerosWhen one or more zeros in a large number are significant, they are shown clearly by writing the number in scientific notation. For example, if the first zero in the measurement 500 m is significant, but the second zero is not, the measurement is written as 5.0 * 102 m. In this text, we will place a decimal point after a significant zero at the end of a number. For example, if a measurement is written as 500. g, the decimal point after the second zero indicates that both zeros are significant. To show this more clearly, we can write it as 5.00 * 102 g. We will assume that zeros at the end of large standard numbers without a decimal point are not significant. Therefore, we write 400 000 g as 4 * 105 g, which has only one significant figure.


Counting Significant Figures

CONCEPT CHECK 2.2 Significant Zeros

Identify the zeros as significant or not significant in each of the following measured numbers:

a. 0.000 250 m b. 70.040 g c. 1 020 000 L

ANSWERa. The zeros preceding the first nonzero digit of 2 are not significant. The zero in the

last decimal place following the 5 is significant.b. Zeros between nonzero digits or at the end of decimal numbers are significant. All

zeros in 70.040 g are significant.c. Zeros between nonzero digits are significant. Zeros at the end of a large number with

no decimal point are placeholders but not significant. The zero between 1 and 2 is significant, but the four zeros following the 2 are not significant.

The number of baseballs is counted, which means 2 is an exact number.

Exact NumbersExact numbers are those numbers obtained by counting items or using a definition that compares two units in the same measuring system. Suppose a friend asks you how many classes you are taking this term. You would answer by counting the number of classes. It is not necessary for you to use any type of measuring tool. Suppose you are asked to state the number of seconds in 1 minute. Without using any measuring device, you would give the definition: 60 seconds is 1 minute. Exact numbers are not measured, do not have a

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2.3 Measured Numbers and Significant Figures

L E A R N I N G G O A L : Identify a number as measured or exact; determine the number of significant figures in a measured number.2.13 What is the estimated digit in each of the following measured

numbers?a. 8.6 m b. 45.25 g c. 29 °C

2.14 What is the estimated digit in each of the following measured numbers?a. 125.04 g b. 5.057 m c. 525.8 °C

2.15 Identify the number1s2 in each of the following as measured or exact:a. A person weighs 67.5 kg.b. The basket holds 8 apples.c. In the metric system, 1 m is equal to 1000 mm.d. The distance from Denver, Colorado, to Houston, Texas,

is 1720 km.

2.16 Identify the number1s2 in each of the following as measured or exact: a. There are 31 students in the laboratory.b. The oldest-known flower lived 1.2 * 108 y ago.

c. The largest gem ever found, an aquamarine, has a mass of 104 kg.

d. A laboratory test shows a blood cholesterol level of 184 mg/dL.

2.17 Identify the measured number1s2, if any, in each of the following pairs of numbers:a. 3 hamburgers and 6 oz of hamburgerb. 1 table and 4 chairsc. 0.75 lb of grapes and 350 g of butterd. 60 s = 1 min

2.18 Identify the measured number1s2, if any, in each of the following pairs of numbers:a. 5 pizzas and 50.0 g of cheeseb. 6 nickels and 16 g of nickelc. 3 onions and 3 lb of onionsd. 5 miles and 5 cars

2.19 Indicate the significant zeros, if any, in each of the following and give a reason:a. 0.0038 m b. 5.04 cm c. 800. Ld. 3.0 * 10-3 kg e. 85 000 g


CONCEPT CHECK 2.3 Significant Figures

Identify each of the following numbers as measured or exact and give the number of significant figures 1SFs2 in each of the measured numbers:

a. 42.2 g b. 3 eggsc. 5.0 * 10-3 cm d. 1 kg = 1000 g

ANSWERa. The mass of 42.2 g is a measured number because it is obtained with a measuring

tool. There are three SFs in 42.2 g because nonzero digits are always significant.b. The value of 3 eggs is an exact number because it is obtained by counting rather than

using a measuring tool.c. The length of 5.0 * 10-3 cm is a measured number because it is obtained with a

measuring tool. There are two SFs in 5.0 * 10-3 cm because all the numbers in the coefficient of a number written in scientific notation are significant.

d. The masses of 1 kg and 1000 g are both exact numbers because the relationship 1 kg = 1000 g is a definition in the metric system of measurement.

limited number of significant figures, and do not affect the number of significant figures in a calculated answer 1see Table 2.52.

TABLE 2.5 Examples of Some Exact Numbers

Counted Numbers Defined Equalities

Items Metric System U.S. System

8 doughnuts 1 L = 1000 mL 1 ft = 12 in.2 baseballs 1 m = 100 cm 1 qt = 4 cups5 capsules 1 kg = 1000 g 1 lb = 16 oz

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2.4 SIGNIFICANT FIGURES IN CALCULATIONS 35

2.4 Significant Figures in CalculationsIn the sciences, we measure many things: the length of a bacterium, the volume of a gas sample, the temperature of a reaction mixture, or the mass of iron in a sample. The numbers obtained from these types of measurements are often used in calculations. The number of significant figures in the measured numbers determines the number of significant figures in the calculated answer.

Using a calculator will help you perform calculations faster. However, calculators cannot think for you. It is up to you to enter the numbers correctly, press the correct func-tion keys, and give an answer with the correct number of significant figures.

Rounding OffSuppose you decide to buy carpeting for a room that measures 5.52 m by 3.58 m. Each mea-surement of length has three significant figures because the measuring tape limits your esti-mated place to 0.01 m. To determine how much carpeting you need, you would calculate the area of the room by multiplying 5.52 times 3.58. If you used a calculator, the display shows the numbers 19.7616. However, this display has too many numbers, which is the result of the multiplication process. Because each of the original measurements has three significant fig-ures, the display numbers of 19.7616 must be rounded off to three significant figures, 19.8. Therefore, you can order carpeting that will cover an area of 19.8 m2 1square meters2.

Each time you use a calculator, it is important to look at the original measurements and determine the number of significant figures that can be used for the answer. You can use the following rules to round off the numbers in a calculator display:

Rules for Rounding Off 1. If the first digit to be dropped is 4 or less, then it and all following digits are simply

dropped from the number. 2. If the first digit to be dropped is 5 or greater, then the last retained digit is increased

by 1.

Number to Round off Three Significant Figures Two Significant Figures

8.4234 8.42 1drop 342 8.4 1drop 2342

14.780 14.8 1drop 80, increase the last retained digit by 12 15 1drop 780, increase the last

retained digit by 123256 3260* 1drop 6, increase the

last retained digit by 1, add 02 13.26 * 1032 3300* 1drop 56, increase the last

retained digit by 1, add 002 13.3 * 1032*The value of a large number is retained by using placeholder zeros to replace dropped digits.


Rounding Off

L E A R N I N G G O A LAdjust calculated answers to give the correct number of significant figures.

2.20 Indicate the significant zeros, if any, in each of the following and give a reason:a. 20.05 °C b. 5.00 m c. 0.000 02 Ld. 120 000 y e. 8.05 * 102 g

2.21 How many significant figures are in each of the following?a. 11.005 kg b. 0.000 32 m3 c. 36 000 000 md. 1.80 * 104 g e. 0.8250 L f. 30.0 °C

2.22 How many significant figures are in each of the following?a. 20.60 mL b. 1036.48 g c. 4.00 md. 20.8 °C e. 60 800 000 kg f. 5.0 * 10-3 L

2.23 Identify the measurement in each of the following pairs that contains more significant figures:a. 11.0 m and 11.00 mb. 405 K and 405.0 Kc. 0.0120 s and 12 000 sd. 2500 mL and 2.50 * 10-2 mL

2.24 Identify the measurement in each of the following pairs that contains more significant figures:a. 28.33 g and 2.8 * 10-3 gb. 0.0250 m and 0.2005 mc. 150 000 s and 1.50 * 104 sd. 3.8 * 10-2 L and 3.80 * 105 L

2.25 Write each of the following in scientific notation with two significant figures:a. 5000 L b. 30 000 gc. 100 000 m d. 0.000 25 cm

2.26 Write each of the following in scientific notation with two significant figures:a. 5 100 000 g b. 26 000 sc. 40 000 m d. 0.000 820 kg

A technician uses a calculator in the laboratory.

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Multiplication and Division with Measured NumbersIn multiplication or division, the final answer is written so that it has the same number of significant figures 1SFs2 as the measurement with the fewest SFs. Some examples of rounding off numbers from multiplication and division follow:

Example 1 Multiply the following measured numbers: 24.65 * 0.67

24.65 17Four SFs

0.67Two SFs Calculator

displayFinal answer,

rounded off to two SFs

=*

Because the calculator display has more digits than the significant figures in the measured numbers allow, we need to round off. Using the measurement that has the fewer number 1two2 of significant figures, 0.67, we round off the calculator display to two significant figures.

Example 2Perform the following operations with measured numbers:

2.850.3741 * 1.50

A problem with multiple steps is worked on a calculator by dividing the number in the numerator by each of the numbers in the denominator.

,,2.85 5.08Three SFs Three SFs Three SFs

0.3741Four SFs

1.50Calculator

display

=

The calculator display is rounded off to give an answer with three significant figures, 5.08.

Adding Significant ZerosSometimes a calculator display consists of a small whole number. Then we add one or more significant zeros to the calculator display to obtain the correct number of significant figures. For example, suppose the calculator display is 4, but you used measurements that have three significant numbers. Then two significant zeros are added to give 4.00 as the correct answer.

4.00

Calculatordisplay

Final answer, two zerosadded to give three SFs

Three SFs

8.002.00

=

A calculator is helpful in working problems and doing calculations faster.

SAMPLE PROBLEM 2.3 Rounding Off�

Round off each of the following numbers to three significant figures:

a. 35.7823 m b. 0.002 621 7 L c. 3.8268 * 103 g

SOLUTIONa. To round off 35.7823 m to three significant figures, drop the numbers 823 and increase

the last retained digit by 1 to give 35.8 m.b. To round off 0.002 621 7 L to three significant figures, drop the numbers 17 to give

0.002 62 L.c. To round off 3.8268 * 103 g to three significant figures, drop the numbers 68 and

increase the last retained digit by 1 to give 3.83 * 103 g.

STUDY CHECK 2.3Round off each of the numbers in Sample Problem 2.3 to two significant figures.

Using Significant Figures in Calculations


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2.4 SIGNIFICANT FIGURES IN CALCULATIONS 37

SAMPLE PROBLEM 2.4 Significant Figures in Multiplication and Division

Perform the following calculations of measured numbers. Give each answer with the correct number of significant figures.

a. 2.07518.422 10.00452 b.

2.0 * 6.004.00

SOLUTION

a.

Four SFs Three SFs Two SFs Calculator

displayFinal answer, rounded

off to two SFs

2.075 558.42 0.0045

Two SFs Three SFs Three SFs Calculatordisplay

Final answer, one significant zero added

to give two SFs

2.0 3.06.00 4.00* ,

, ,

=

=

b.

Four SFs Three SFs Two SFs Calculatordisplay

Final answer, roundedoff to two SFs

2.075 558.42 0.0045

Two SFs Three SFs Three SFs Calculatordisplay

Final answer, one significant zero added

to give two SFs

2.0 3.06.00 4.00* ,

, ,

=

=

STUDY CHECK 2.4Perform the following calculations of measured numbers and give the answers with the correct number of significant figures:

a. 45.26 * 0.010 88 b. 4.0 * 8.00

16

Addition and Subtraction with Measured NumbersIn addition or subtraction, the final answer is written so that it has the same number of decimal places as the measurement having the fewest decimal places. Some examples of addition and subtraction follow:

Example 3Add: 2.367 Thousandths place

+ 34.1 Tenths place

36.467 Calculator display

36.5 Answer, rounded off to tenths place

Example 4Subtract: 255 Ones place

- 175.65 Hundredths place

79.35 Calculator display

79 Answer, rounded off to the ones place

When numbers are added or subtracted to give an answer ending in zero, that zero does not appear after the decimal point in the calculator display. For example, 14.5 g - 2.5 g = 12.0 g. However, when you do the subtraction on your calculator, the calculator display shows 12. The correct answer, 12.0 g, is obtained by placing a signifi-cant zero after the decimal point.

Example 5 Subtract: 14.5 g Tenths place

- 2.5 g Tenths place

12. Calculator display

12.0 g Answer, zero written after the decimal point to give a digit in the tenths place

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2.4 Significant Figures in Calculations�

L E A R N I N G G O A L : Adjust calculated answers to give the correct number of significant figures.2.27 Why do we usually round off the calculator display of a cal-

culation that includes measured numbers?

2.28 Why do we sometimes add a zero to a number in a calculator display of a calculation that includes measured numbers?

2.29 Round off each of the following measurements to three sig-nificant figures:a. 1.854 kg b. 88.0238 L c. 0.004 738 265 cmd. 8807 m e. 1.8329 * 103 s

2.30 Round off each of the measurements in Problem 2.29 to two significant figures.

2.31 Round off or add zeros to each of the following to give an answer with three significant figures:a. 56.855 m b. 0.002 282 g c. 11 527 s d. 8.1 L

2.32 Round off or add zeros to each of the following to give an answer with two significant figures:a. 3.2805 m b. 1.855 * 102 gc. 0.002 341 mL d. 2 L

2.33 Perform each of the following calculations, and give an answer with the correct number of significant figures:a. 45.7 * 0.034 b. 0.002 78 * 5

c. 34.561.25

d. 10.246521252

1.78e. 12.8 * 104215.05 * 10-62

f. 13.45 * 10-2211.8 * 105218 * 1032

2.34 Perform each of the following calculations, and give an answer with the correct number of significant figures:

a. 400 * 185 b. 2.4014211252

c. 0.825 * 3.6 * 5.1 d. 13.5210.261218.242120.02

e. 15 * 10-5211.05 * 104218.24 * 10-82

f. 14.25 * 102212.56 * 10-3212.245 * 10-32156.52

2.35 Perform each of the following calculations, and give an answer with the correct number of decimal places:a. 45.48 cm + 8.057 cm b. 23.45 g + 104.1 g + 0.025 gc. 145.675 mL - 24.2 mL d. 1.08 L - 0.585 L

2.36 Perform each of the following calculations, and give an answer with the correct number of decimal places:a. 5.08 g + 25.1 gb. 85.66 cm + 104.10 cm + 0.025 cmc. 24.568 mL - 14.25 mL d. 0.2654 L - 0.2585 L


SAMPLE PROBLEM 2.5 Significant Figures in Addition and Subtraction

Perform the following calculations and give the answers with the correct number of decimal places:

a. 104.45 mL + 0.838 mL + 46 mL b. 153.247 g - 14.82 g

SOLUTIONa. 104.45 mL Hundredths place

0.838 mL Thousandths place

+ 46 mL Ones place

151 mL Answer, rounded off to the ones place

b. 153.247 g Thousandths place

- 14.82 g Hundredths place

138.43 g Answer, rounded off to hundredths place

STUDY CHECK 2.5Perform the following calculations and give the answers with the correct number of decimal places:

a. 82.45 g + 1.245 g + 0.000 56 g b. 4.259 L - 3.8 Lc. 0.385 m + 12.5 m - 5.85 m

2.5 Prefixes and EqualitiesIn the metric and SI systems of units, a prefix attached to any unit increases or decreases its size by some factor of 10. Table 2.6 lists some of the SI and metric prefixes, their sym-bols, and their numerical values.

L E A R N I N G G O A LUse the numerical values of prefixes to write a metric equality.

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2.5 PREFIXES AND EQUALITIES 39

The prefix centi is like cents in a dollar. One cent would be a centidollar, or 0.01 of a dollar. That also means that one dollar is the same as 100 cents. The prefix deci is like the value of a dime to a dollar. One dime would be a decidollar, or 0.1 of a dollar. That also means that one dollar has the same value as 10 dimes.

The relationship of a prefix to a unit can be expressed by replacing the prefix with its numerical value. For example, when the prefix kilo in kilometer is replaced with its value of 1000, we find that a kilometer is equal to 1000 m. Other examples follow:

1 kilometer 11 km2 = 1000 meters 11000 m = 103 m2 1 kiloliter 11 kL2 = 1000 liters 11000 L = 103 L2 1 kilogram 11 kg2 = 1000 grams 11000 g = 103 g2

CONCEPT CHECK 2.4 Prefix Values

Fill in the blanks with the correct prefix:

a. 1000 g = 1 g b. 0.01 m = 1 m c. 1 * 106 L = 1 L

ANSWERa. The prefix for 1000 is kilo; 1000 g = 1 kgb. The prefix for 0.01 is centi; 0.01 m = 1 cmc. The prefix for 1 * 106 is mega; 1 * 106 L = 1 ML


Using Prefixes

TABLE 2.6 Metric and SI Prefixes

Prefix Symbol Numerical Value Scientific Notation Equality

Prefixes That Increase the Size of the Unit

peta P 1 000 000 000 000 000 1015 1 Pg = 1 * 1015 g1 g = 1 * 10-15 Pg

tera T 1 000 000 000 000 1012 1 Ts = 1 * 1012 s1 s = 1 * 10-12 Ts

giga G 1 000 000 000 109 1 Gm = 1 * 109 m1 m = 1 * 10-9 Gm

mega M 1 000 000 106 1 Mg = 1 * 106 g1 g = 1 * 10-6 Mg

kilo k 1 000 103 1 km = 1 * 103 m1 m = 1 * 10-3 km

Prefixes That Decrease the Size of the Unit

deci d 0.1 10-1 1 dL = 1 * 10-1 L1 L = 10 dL

centi c 0.01 10-2 1 cm = 1 * 10-2 m1 m = 100 cm

milli m 0.001 10-3 1 ms = 1 * 10-3 s1 s = 1 * 103 ms

micro m 0.000 001 10-6 1 mg = 1 * 10-6 g1 g = 1 * 106 mg

nano n 0.000 000 001 10-9 1 nm = 1 * 10-9 m1 m = 1 * 109 nm

pico p 0.000 000 000 001 10-12 1 ps = 1 * 10-12 s1 s = 1 * 1012 ps

femto f 0.000 000 000 000 001 10-15 1 fs = 1 * 10-15 s1 s = 1 * 1015 fs

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BASIC CHEMISTRY - aswarphysics.weebly.com · Basic Chemistry , Fourth Edition, and uses new terms during the lab and explores chemical concepts. Laboratory investiga - tions develop