Chapter 1 and 2

Introduction to Chemistry and

Measurements and Calculations

How to be successful in Chemistry!________1. Attend class in body, mind, and spirit?________2. Keep an organized, complete notebook?________3. Read and take my own notes on every lesson, including sample problems?________4. Compare my notes with Ms. Neiman’s notes when in doubt?________5. Constantly ask myself if the material makes sense?________6. Ask questions (in class, email, phone) AS SOON AS I do not understand something? ________7. Attempt homework with closed notes?________8. Review new and old material each night?________9. Do every assignment?________10. Do even-numbered problems (answers in back of book) for extra practice?________11. Get extra help after school or in study hall when needed?________12. Sit in on an extra class in material I am struggling with?________13. Work with study buddies on homework problems and for test review?________14. Get extra practice with the CD (math practice) if needed?________15. Review notes and practice problems each night?________16. Ask questions about problems that were not solved correctly?________17. Try to relate what is being taught to everyday life?________18. Make note of concepts already mastered?________19. Focus studying on concepts not mastered?________20. Ask Ms. Neiman for HELP BEFORE DISASTER STRIKES??!!

Lesson Objectives

• Define CHEMISTRY• Define MATTER• Define ITERATIVE PROCESS• Explain the steps of the Scientific Method• Discuss experimental design in regard to

control, independent variable and dependent variable

• Identify the control, independent variable and dependent variable in an experimental description

What is Chemistry?

• Chemistry- »The study of matter and the changes that occur

to matter

• Matter- »Anything that has mass and volume

»Anything that has mass and takes up space

How do we study Matter?

• Scientific Method»Process for scientific inquiry» It is an Iterative process

• Iterative Process»a process that may involve backing up

and or repeating to complete the entire process successfully

Scientific Method

• Scientific Method Handout

»Do NOT memorize the chart»Understand the process/steps

3 Features of Experimental Design• Control

» The portion of the experiment that is not changed or altered, necessary to be able to see unexpected influences

• Independent Variable» The factor being deliberately altered

• Dependent Variable» The factor being measured to determine the results

Example of Experimental DesignBean plants were studied to examine the influence of a new fertilizer. One set of plants received no fertilizer, another set 1 lb per week and the other set 2 lbs per week of the new fertilizer. The height of the plants was recorded daily.

Identify the:Control- Independent Variable- Dependent Variable-

Scientific Method/Experimental Design Activity

• In Class Objective:• Identify the steps of the Scientific Method in a scenario

description• In partners (group of 3 only if necessary) identify the

steps of the scientific method and also identify the parts of a properly designed experiment using the “An Adventure with Peas” handout.

An Adventure with Peas

Assignment

• Complete “Scenario 2: Alka-Seltzer Speed Race” using the same directions as the front of the page.

• Create your own Science Experiment Scenario• Must have all steps of the Scientific Method• Must have all three aspects of a properly designed experiment• School appropriate topic in story/sentence/paragraph format• Do NOT identify the steps or aspects… we will do this next class

period as a partner activity.

Objectives:

• Explain the difference between a law and a theory

• Explain the difference between qualitative and quantitative observations

• Provide an example of (or identify an observation as) a qualitative observation or quantitative observation

Laws and Theories

• Law: •a statement that summarizes what happens

• Theory: •Statement that attempts to explain why it happens•Models are theories

Types of Observations• Qualitative:

• Observations that record non numeric data• Involve the senses

» Sight» Smell» Sound» Feel » Taste ** Note: tasting is not permissible in chemistry class

due to safety considerations

• Cannot have numbers if qualitative• Examples:

» Red car» The socks smell bad.» The band sounds very loud.» The floor is smooth» School lunch is yummy!

Types of Observations

• Quantitative:• Observations that record numeric data• Counting, measuring• MUST have NUMBERS to be quantitative!• Examples:

» 5 apples» The block weighs 9 kilograms» 25 milliliters of acid» I scored a 95% in Chemistry» 0.29 grams of sand

PracticePlace the statements in the correct category

Qualitative Quantitative

The car is rusty

My book is 12 centimeters longSally is 5’9” tall.

Apples are yummy!

I have 25 liters of gas

Work stinks!

I hear birds singing.

There are 15 students.

Jan is tall.

The room smells like onions.

The cow is big. In five days I get my permitI scored an 89% my quiz.

More practice: Look at the objects shown to you. Describe it using both qualitative and quantitative observations.

Qualitative Quantitative

More practice: Look around your Chemistry room. Describe it using both qualitative and quantitative observations.

Qualitative Quantitative

Assignment

Choose a room in your house.• Record 5 qualitative observations• Record 5 quantitative observations• write or type your observations on a separate piece of

paper• Do not put them in categories, scatter the

observations like the exercise we did in class.

Bring the paper to class tomorrow!

In Class Assignment

• Make sure you name is on your paper- exchange papers

• New person- put your name followed by “Organizer"

• Put each observation in the correct category: Qualitative or Quantitative

Objectives:

• Explain how/why scientific notation is used• Express ordinary decimal numbers in scientific

notation• Express numbers in scientific notation in

ordinary decimal form• Enter a number in scientific notation into a

calculator • Properly record a number given in scientific

notation on a calculator onto paper

Scientific Notation (Chapter2 Section1)

Scientific Notation:• Method of expressing very large or very small

numbers in a more compact manner.• Using a number between 1 and 10 and a power

of 10 to express very large or very small numbers• Examples:

» 4.5x10-3 is the same as 0.0045» 3.2x105 is the same as 320000

Scientific Notation In Action

From Standard Decimal form to Scientific Notation Move decimal so only 1 non zero number remains to the left (in front of) of the decimal. Count number of moves and use this number as the exponent, make the exponent negative for numbers less than 1

• For Numbers Larger than 1• Example: 93,000,000 Answer: 9.3x107

• For Numbers Smaller than 1• Example: 0.000167 Answer: 1.67x10-4

Scientific Notation In Action

From Scientific Notation to Standard Decimal formMove decimal according to exponent number. Negative exponents make numbers smaller than 1, positive exponents make numbers larger than 1.

• For Numbers with positive exponents• Example: 1.5x105 Answer: 150,000

• For Numbers with negative exponents• Example: 2.6x10-8 Answer: 0.000000026

Scientific Notation Practice Express the following in Scientific Notation

1. 10,000 2. 0.0001 3. 10,000,000,000 4. 790,000 5. 0.0000462 6. 0.000000089 7. 371 8. 0.96300 9. 178,034,000 10. 0.000450000

Answers1) 1 x 104

2) 1 x 10-4

3) 1 x 1010 4) 7.9 x 105

5) 4.62 x 10-5 6) 8.9 x 10-8

7) 3.71 x 102

8) 9.63 x 10-1

9) 1.78034 x 108

10) 4.5 x 10-4

Scientific Notation Practice Express the following in Ordinary Decimal Form

1. 4 x 102

2. 2.6 x 10-5

3. 3.89 x 107 4. 5.2 x 104

5. 4.3 x 10-3

6. 9.5 x 10-9 7. 4.00 x 105

8. 3.7 x 10-1

9. 1.34087 x 109 10. 6.48 003 x 10-7

Answers1) 4002) 0.0000263) 38,900,0004) 520005) 0.0043 6) 0.00000000957) 400,0008) 0.379) 1,340,870,00010) 0.000000648003

Assignment

• Page 46 #5, 7

Answers

Objectives:

• Define measurement (2 key components)• Explain why units are necessary• Determine to which system (English or

Metric/SI) a unit belongs• Recognize the standard SI units for length,

mass, volume, time and temperature• Recognize metric prefixes and the associated

symbol and numeric exponent for each prefix

Measurement

• Measurement:• Is another name for Quantitative data• Data that contains numbers .• Measurements MUST have a number and a unit

• Units are an important part of any measurement… don’t forget them!

Why are units necessary??

Pay close attention to Neiman's story!

• So… Why are units necessary?

Units

• Units tell us what standard is being used to determine the measurement

• Two systems of units – English System – USA is one of few places this is

still in use– Metric System – Most countries use this system

International System

• le Systeme Internationale (French)

• SI System is used for scientific work

• Based on the metric system and is a comprehensive system of units

The Important SI Units (Standard Units)

•Mass -- kilogram ***• Length-- meter• Volume-- liter• Time -- second• Temperature-- Kelvin

The Metric System

Objectives:

• Define Dimensional Analysis• Define Equivalence Statement• Define Conversion Factor• Use Dimensional Analysis to convert from

English to Metric units• Use Dimensional Analysis to convert

between different Metric units

How To Convert

• Dimensional Analysis:A method of problem solving using unit cancellation

• Equivalence Statement:a mathematical equality showing the relationship between two units

• Conversion Factor:Are derived from equivalence statements and are used to convert 1 unit to another. They look like fractions.

Conversion Factors• For every equivalence statement there are

two conversion factors.• Example:

12 inches = 1 foot

12 inches or 1 foot 1 foot 12 inches

Which one you need depends on what you are converting.

Using Dimensional Analysis• How many donuts are in 3 dozen donuts?

12 donuts = 1 dozen

12 donuts or 1 dozen 1 dozen 12 donuts

36donutsdozen 1

donuts 12 3dozen

Using Dimensional Analysis

• How many seconds are in 1 year?

Metric Conversions• Convert 250 meters to kilometers

• 1x103 m = 1 Km

• Convert 250 millimeters to decimeters• 1x102 mm = 1 dm• 1x10-3 m = 1mm and 1x10-1 m = 1 dm

Assignment

• Page 46-9 # 1, 17, 59,61,63

Answers

Objectives:• Define Density • Identify the formula and units for density

calculations• Discuss the two different ways to determine the

volume of an object in the lab • Use the formula for density to solve problems when

given any two of the following three variables: mass, volume, density

• Recognized the three different temperature scales• Use formulas to convert among the three

temperature scales

Density• What is Density:

• the amount of matter in a given space• the amount of matter in a given volume

• Formula:• Density = mass ÷ volume

• Density Units:• g/mL• g/cm3

Measuring volume for Density calculations

• Water Displacement:• method for measuring the volume of irregular

objects• Submerge object in graduated container with known

amount of liquid, determine amount of liquid displaced by the object.

• Linear Measurement:• method for measuring regular geometric objects• Use ruler, meter stick, etc to determine dimensions

of the object, a geometric formula is needed (LxWxH)

Really Interesting and Important

1 mL = 1 cm3

Calculations using Density

• Mass and Volume 23.50 mL , 35.062 g

• Mass and Density 13.6 g/mL , 225 g

• Density and Volume 0.880 g/mL , 35 mL

Assignment

• Density Worksheet 1-10 all

Temperature Conversion

• There are 3 Temperature Scales• Fahrenheit•Celsius•Kelvin

Objectives:

• Define Specific Gravity• Explain why specific gravity does not have

units

Specific Gravity

• What is Specific Gravity??• A ratio that compares the density of a given liquid to

the density of water.

• Why no Units??• Specific gravity does not have units because it is a ratio

of same type units and therefore the units cancel.

Objectives:

• Define Significant Figures• Use significant figures to express uncertainty

in measurements• Use significant figures to round calculated

answers

**Please note: the terms Significant Figures and Significant Digits are interchangeable!!

Uncertainty in Measurement

• Significant Figures:• The recorded numbers of a measurement, all

certain numbers plus the first estimated number.

• Indicate the level of certainty of an answer.

• Significant Figure Rules:

Adobe Acrobat Document

Follow the rules:• How many significant digits?

42.093 0.00345 9.0000 5 sig figs 3 sig figs 5 sig figs

1000 9.00045 1.00891 sig fig 6 sig figs 5 sig figs

1000.0 0.0009008 0.008900005 sig figs 4 sig figs 6 sig figs

End of Chapter 1 and 2