CHAPTER 14, 16 & 18 WHAT IS CHEMISTRY? Balloon Demonstration (Conceptual Integrated Science Explorations: p.259) Hypothesis what will happen when you fill the balloon with the fragrance? Hypothesis what will happen when you fill the balloon with the fragrance? 1. Get balloon & smell it record 2. Fill balloon with fragrance & then fill with air smell & record 3. Answer questions 1 & 2 under Analyze & conclude on pg 259 Questions Open your BOOK to page 273 and answer questions: Open your BOOK to page 273 and answer questions: Bill Nye the Science Guy! ATOMSYJS0&feature=endscreen&NR=1 (Full video - 22:11)YJS0&feature=endscreen&NR=1 (Full video - 22:11)YJS0&feature=endscreen&NR=1YJS0&feature=endscreen&NR=1h3WPk (video clip - 6:37)h3WPk (video clip - 6:37)h3WPkh3WPk Chapter 14: The Atom 14.1 & 14.2: The Atom Submicroscopic (smaller than microscope level!) particles. Teeny-tiny basic units that make up stuff Submicroscopic (smaller than microscope level!) particles. Teeny-tiny basic units that make up stuff 1 grain of sand contains around 125 MILLION TRILLION atoms. 1 grain of sand contains around 125 MILLION TRILLION atoms. The # of atoms in a baseball is equivalent to the # of ping-pong balls that could fit inside Earth The # of atoms in a baseball is equivalent to the # of ping-pong balls that could fit inside Earth There are more than 100 different kinds & are listed on the periodic table There are more than 100 different kinds & are listed on the periodic table Parts of an Atom Atoms are made up of EVEN SMALLER particles Atoms are made up of EVEN SMALLER particles Subatomic particles: Subatomic particles: Protons (positive charge) Neutrons (no charge) Electrons (negative charge) The Atom Atomic Nucleus & Electrons Atomic Nucleus - core of atom, makes up most of atoms mass, consists of PROTONS & NEUTRONS. Atomic Nucleus - core of atom, makes up most of atoms mass, consists of PROTONS & NEUTRONS. ELECTRONS buzz around the empty space surrounding the nucleus. Negative charge ELECTRONS buzz around the empty space surrounding the nucleus. Negative charge 14.3: Protons & Neutrons PROTON heavy particle in the nucleus thats positively (electric) charged. Has SAME quantity but OPPOSITE charge of electron PROTON heavy particle in the nucleus thats positively (electric) charged. Has SAME quantity but OPPOSITE charge of electron NEUTRON same mass as proton, but no charge, also found in the nucleus. NEUTRON same mass as proton, but no charge, also found in the nucleus. Nucleons - general term for subatomic particles in the nucleus: protons & neutrons Nucleons - general term for subatomic particles in the nucleus: protons & neutrons Atomic Number = to the number of PROTONS in atomic nucleus = to the number of PROTONS in atomic nucleus Order of elements Order of elements Ex: Ex: Hydrogen (H) has 1 proton per atom, the atomic number Helium (He) has 2 protons in nucleus & atomic number is 2 Which element does the diagram represent? Which element does the diagram represent? Nitrogen! Which atom does this diagram represent? OXYGEN! Periodic Table of Elements pages & 16.6 ELEMENTS Any material made of only one type of atom Any material made of only one type of atom Elements are the building blocks of matter Elements are the building blocks of matter There are 115 known elements today, 90 which occur naturally There are 115 known elements today, 90 which occur naturally All elements are listed in a chart called the PERIODIC TABLE All elements are listed in a chart called the PERIODIC TABLE ELEMENTS (Cont) Each element has a unique symbol Each element has a unique symbol The first letter is always capitalized, the second letter is always lower case Fluorine is F, not f Cobalt is Co, not CO (which is carbon monoxide) Oxygen is O The smallest unit of an element is the atom The smallest unit of an element is the atom Atomic Symbol Each element has a unique symbol Each element has a unique symbol The first letter is always capitalized, the second letter is always lower case Fluorine is F, not f Cobalt is Co, not CO (which is carbon monoxide) Oxygen is O Groups Vertical column of table Vertical column of table Also called a family Also called a family All elements in the same Group have similar properties All elements in the same Group have similar properties Ex: Noble Gases - He, Ne, & Ar are all gases Groups contd Group Names Group 1: Alkali Metals Group 1: Alkali Metals Group 2: Alkaline-earth Metals Group 2: Alkaline-earth Metals Group 3 12: Transition Metals Group 3 12: Transition Metals Group 13 15: No Common Name Group 13 15: No Common Name Group 16: Chalcogens Group 16: Chalcogens Group 17: Halogens Group 17: Halogens Group 18: Noble Gases Group 18: Noble Gases Periods Horizontal row Horizontal row Across any period (horizontal row) the properties of elements gradually change called a periodic trend Across any period (horizontal row) the properties of elements gradually change called a periodic trend Trends repeat from one row to the next Trends repeat from one row to the next Periods Ex: Atom Size - atoms get smaller as you move from left to right Ex: Atom Size - atoms get smaller as you move from left to right BIGGER to smaller 14.4: Mass Number Mass Number: the total number of protons and neutrons (total number of nucleons) Mass Number: the total number of protons and neutrons (total number of nucleons) Hydrogen-1Hydrogen-2Hydrogen-3 14.4: Isotopes Isotopes: any member of a set of atoms of the same element whose nuclei contain the same number of protons but different numbers of neutrons Isotopes: any member of a set of atoms of the same element whose nuclei contain the same number of protons but different numbers of neutrons mass number atomic # = # of neutrons mass number atomic # = # of neutrons Ex: Iron Fe Ex: Iron Fe 2626 Isotope Examples Iron-56 & Iron-55 Iron-56 & Iron-55 How many neutrons are in each? (Hint: See PT) How many neutrons are in each? (Hint: See PT) Iron-56: 56 26 = 30 neutrons Iron-56: 56 26 = 30 neutrons Iron-55: 55 26 = 29 neutrons Iron-55: 55 26 = 29 neutrons 7 Li isotope 7 Li isotope How many neutrons are in lithium? How many neutrons are in lithium? 7 3 = 4 neutrons 7 3 = 4 neutrons If an atom has 6 electrons, 8 neutrons, and 6 protons, what is the mass number? What is the element? If an atom has 6 electrons, 8 neutrons, and 6 protons, what is the mass number? What is the element? mass number = 14, the element is Carbon mass number = 14, the element is Carbon 3 Isotopes Use a Periodic Table to complete the following table IsotopeMass Number Isotope Notation ProtonsElectronsNeutrons Hydrogen-1 Chlorine-? 19 Nitrogen-14 Potassium-40 Arsenic-? 42 Gold-197 Isotopes Answers IsotopeMass Number Isotope Notation ProtonsElectronsNeutrons Hydrogen-1 1 1H1H 110 Chlorine Cl Nitrogen N 777 Potassium K Arsenic As Gold Au Isotopes Use a Periodic Table to complete the following table IsotopeMass #Isotope Notation Atomic #ProtonsElectronsNeutrons Oxygen-16 Calcium Copper Isotopes Answers IsotopeMass #Isotope Notation Atomic # ProtonsElectronsNeutrons Oxygen O8 888 Calcium Ca 20 Krypton Kr Copper Cu Selenium Se Phosphorus P Atomic Mass Atomic Mass: The sum of the masses of all the atoms electrons, protons and neutrons Atomic Mass: The sum of the masses of all the atoms electrons, protons and neutrons 14.5: Electron Shells Within the atom, electrons behave as though they are arranged in shells. Within the atom, electrons behave as though they are arranged in shells. Each shell can hold a certain number of electrons Each shell can hold a certain number of electrons Innermost shell: 2 Shells 2-3: 8 each Shells 4-5: 18 each Shells 6-7: 32 each Bohrs Shell Model Make a shell model for the following atoms: Make a shell model for the following atoms: Fluorine Neon Chlorine Argon Iron Arsenic Valence Electrons Electron in outermost shell of an atom Electron in outermost shell of an atom Atoms combine to form molecules by valence electrons Atoms combine to form molecules by valence electrons combining power of an atom combining power of an atom Chapter 16: Elements of Chemistry 16.1: Chemistry: The Central Science Chemistry is the study of matter and the transformations it can undergo. Chemistry is the study of matter and the transformations it can undergo. What is matter? What is matter? Anything that has mass and takes up space. IMPORTANCE OF CHEMISTRY Chemistry is all around you. Chemistry is all around you. Air you breathe Food you digest Clothes you wear Textbook you read Chemistry is often said to be the central science. Chemistry is often said to be the central science. Syringe Activity Materials: Syringe, cup of water, mini marshmallow, (rubber stopper) Materials: Syringe, cup of water, mini marshmallow, (rubber stopper) Do the following & Record observations Do the following & Record observations 1. Double the pressure 2. Quadruple the pressure 3. Reduce volume in half let go of plunger 4. 0mL, block end & try to lift plunger all the way out Indicates atmospheric pressure Indicates atmospheric pressure 5. Add marshmallow. Pressurize it as much as possible. 6. Start with plunger close to marshmallow. Cover end and try to lift plunger. 7. Remove marshmallow. Completely fill syringe with water. Compress syringe Why was it hard to quadruple pressure? What was happening to the air particles inside as you tried to add pressure? Why was it so hard to lift the plunger out of the syringe? Why did the marshmallow respond as it did to the changes in pressure? Why cant you compress water? 16.2: The Submicroscopic World Submicroscopic beyond the microscopic level. Atoms & molecules Submicroscopic beyond the microscopic level. Atoms & molecules Molecules - some atoms link together to form larger but still incredibly small units of matter called molecules Molecules - some atoms link together to form larger but still incredibly small units of matter called molecules Phases of Matter Liquid matter that has a definite volume but no definite shape, assumes shape of container Liquid matter that has a definite volume but no definite shape, assumes shape of container Solid matter that has definite shape & volume Solid matter that has definite shape & volume Gas matter that has neither definite volume nor definite shape, fills any space available Gas matter that has neither definite volume nor definite shape, fills any space available PHASES OF MATTER Complete the following chart: Copyright 2005 by Pearson Education, Inc. Publishing as Benjamin Cummings SOLIDLIQUIDGAS SHAPE VOLUME Arrangement of Particles Interaction between Particles Movement of Particles Example PHASES OF MATTER Complete the following chart: Copyright 2005 by Pearson Education, Inc. Publishing as Benjamin Cummings SOLIDLIQUIDGAS SHAPEDefinite shapeShape of container VOLUMEDefinite volume Volume of container Arrangement of Particles Fixed, very closeRandom, closeRandom, far apart Interaction between Particles Very strongStrongEssentially none Movement of Particles Very slowModerateVery fast ExampleIce, salt, ironWater, oil, vinegarWater vapor, helium, air WATER AND ITS STATES OF MATTER 16.3: Changes of Phase In order to change the phase of a substance, you must either add heat or remove heat In order to change the phase of a substance, you must either add heat or remove heat Change of Phase Melting: Solid to liquid Melting: Solid to liquid Boiling: Liquid to gas (beneath the surface) Boiling: Liquid to gas (beneath the surface) Evaporation: Liquid to gas (surface) Evaporation: Liquid to gas (surface) The above 3 require input of heat energy Condensation: Gas to liquid Condensation: Gas to liquid Freezing: Liquid to solid Freezing: Liquid to solid The above 2 release heat energy Melting Boiling & Evaporation Freezing Condensation Change of Phase Diagram 16.4: Physical & Chemical Properties & Changes PHYSICAL PROPERTIES Any physical attribute of a substance such as color, density, texture, hardness, & phase Any physical attribute of a substance such as color, density, texture, hardness, & phase Each substance has unique physical properties Each substance has unique physical properties Examples Examples Sulfur appears as a yellow powder The boiling point of water is 100 o C Carbon monoxide is odorless PHYSICAL CHANGES Change in substances physical property but doesnt change the composition Change in substances physical property but doesnt change the composition Examples include: Any change in the state of matter (e.g. freezing or boiling water) Sawing wood Crushing a tablet Bending a wire Dissolving salt in water CHEMICAL PROPERTIES Describe ways pure substances behave when interacting with other pure substances. Describe ways pure substances behave when interacting with other pure substances. Examples Examples Iron reacts with oxygen to form rust. Platinum does not react with oxygen at room temperature. CHEMICAL CHANGES Changes the identity of the substance as the chemical composition changes. Changes the identity of the substance as the chemical composition changes. Also called chemical reactions Examples: Examples: Tarnishing of silver (Ag forms AgS) (Ag forms AgS) Rusting of iron (Fe forms Fe 2 O 3 ) (Fe forms Fe 2 O 3 ) 16.5: Determining Physical & Chemical Changes Molecules:Change in physical appearance? New material or same after returning to original conditions? New material that has its own unique set of physical properties? Examples: Physical Chemical 16.5: Determining Physical & Chemical Changes Molecules:Change in physical appearance? New or same material after returning to original conditions? New material that has its own unique set of physical properties? Examples: PhysicalMolecules are the same as started with yessameno Ice melting Potassium chromate ChemicalOriginal molecules have been destroyed & new ones are in place yesnewyes Iron turning to rust Ammonium dichromate CHEMICAL REACTIONS Are the same as a chemical change Are the same as a chemical change Are expressed using chemical equations. Are expressed using chemical equations. Rusting of iron: Rusting of iron: 4 Fe + 3 O 2 2 Fe 2 O 3 (rust) reactants products reactants productsMeaning: Four atoms of iron react with three molecules of oxygen to form two molecules of rust The Law of Conservation of Matter/Mass Matter can neither be created nor destroyed in an isolated system Matter can neither be created nor destroyed in an isolated system Brain Pop: Chem equations & Conservation of Matter/Mass Brain Pop: Chem equations & Conservation of Matter/Mass CHEMICAL REACTIONS (Cont) Zn + 2 HCl ZnCl 2 + H 2 Zinc hydrochloric acid zinc chloride hydrogen gas Meaning: One atom of zinc reacts with two molecules of hydrochloric acid to produce one molecule of zinc chloride and one molecule of hydrogen gas. How to Balance Chemical Equations 1. Write the unbalanced equation. Chemical formulas of reactants are listed on the left-hand side Chemical formulas of reactants are listed on the left-hand side Products are listed on the right-hand side Products are listed on the right-hand side Reactants and products are separated by putting an arrow between them to show the direction of the reaction. Reactants and products are separated by putting an arrow between them to show the direction of the reaction. 2. Balance the equation. Apply the Law of Conservation of Mass to get the same number of atoms of every element on each side of the equation. Apply the Law of Conservation of Mass to get the same number of atoms of every element on each side of the equation.Law of Conservation of MassLaw of Conservation of Mass Start by balancing an element that appears in only one reactant and product. Start by balancing an element that appears in only one reactant and product. Once one element is balanced, proceed to balance another, and another, until all elements are balanced. Once one element is balanced, proceed to balance another, and another, until all elements are balanced. Balance chemical formulas by placing COEFFICENTS in front of them. DO NOT add subscripts, because this will change the formulas. Balance chemical formulas by placing COEFFICENTS in front of them. DO NOT add subscripts, because this will change the formulas. Practice Balancing Equations 1 __Fe + __Cl 2 __FeCl 3 2 __Al + __O 2 __Al 2 O 3 3 __CH 4 + __ O 2 __ CO 2 + __ H 2 O 4 __ Na + __ Cl 2 ___ NaCl 5 __ N 2 + __ H 2 ___ NH 3 6 __ Al + __ HCl __ AlCl 3 + ___ H 2 Practice Balancing Equations: ANSWERS _2_Fe + _3_Cl 2 _2_FeCl 3 _2_Fe + _3_Cl 2 _2_FeCl 3 _4_Al + _3_O 2 _2_Al 2 O 3 _4_Al + _3_O 2 _2_Al 2 O 3 Balancing Chemical Equations Modeling Clay Activity Use modeling clay to represent each element to balance the chemical equations on the chart. Use modeling clay to represent each element to balance the chemical equations on the chart. Example: Example: Fe + Cl 2 FeCl 3 Fe (iron) = YELLOW clay Cl (chlorine) = BLUE clay Balancing Chemical Equations Modeling Clay Activity Use modeling clay to represent each element to balance the chemical equations on the chart on the next slide. Use modeling clay to represent each element to balance the chemical equations on the chart on the next slide. Example: Example: Fe + Cl 2 FeCl 3 Fe (iron) = YELLOW clay Cl (chlorine) = BLUE clay Balancing Chemical Equations Modeling Clay Activity Make the equations on your desk Reactants (Start) Products (Start) Balanced Equation Reactants (Final) Products (Final) H 2 + O 2 H 2 O H 2 O 2 H 2 O + O 2 Na + O 2 Na 2 O N 2 + H 2 NH 3 P 4 + O 2 P 4 O 10 Fe + H 2 O Fe 3 O 4 + H 2 C + H 2 CH 4 Na 2 SO 4 + CaCl 2 CaSO 4 + NaCl C 2 H 6 + O 2 CO 2 + H 2 O Al 2 O 3 Al + O 2 CLASSIFICATION OF MATTER ELEMENTS (you have these notes already) Any material made of only one type of atom Any material made of only one type of atom Elements are the building blocks of matter Elements are the building blocks of matter There are 115 known elements today, 90 which occur naturally There are 115 known elements today, 90 which occur naturally The periodic table displays the elements The periodic table displays the elements ELEMENTS (Cont) (you have these notes already) Each element has a unique symbol Each element has a unique symbol The first letter is always capitalized, the second letter is always lower case Fluorine is F, not f Cobalt is Co, not CO (which is carbon monoxide) Oxygen is O The smallest unit of an element is the atom The smallest unit of an element is the atom COMPOUNDS Atoms of different elements bond to one another to make a compound Atoms of different elements bond to one another to make a compound NaCl (table salt) Contains sodium (Na) and chlorine (Cl) NaCl is the chemical formula H 2 O (water) Contains 2 atoms of hydrogen (H) and 1 atom of oxygen (O) H 2 O is the chemical formula Elements in compounds are combined in a definite ratio Elements in compounds are combined in a definite ratio H 2 O is water but H 2 O 2 is hydrogen peroxide COMPOUNDS (cont) Are H 2 and O 3 considered elements or compounds? Why? Are H 2 and O 3 considered elements or compounds? Why? Heterogeneous Mixture The different components can be seen as individual substances The different components can be seen as individual substances Different parts are visible Different parts are visible Ex: Pulp in orange juice, sand in water, oil & water, pizza Ex: Pulp in orange juice, sand in water, oil & water, pizza Homogeneous Mixture Have same composition throughout Have same composition throughout Cant see separate parts Cant see separate parts Ex: Air, blood, fog, salt water Ex: Air, blood, fog, salt water CLASSIFICATION OF MATTER Classify the following as an element, compound, homogeneous mixture, or heterogeneous mixture. a.Fog b.Gasoline c.Helium d.Sulfuric acid (H 2 SO 4 ) e.Orange juice from squeezed oranges f. H 2 PRACTICE PROBLEM Identify the following properties and changes as physical or chemical. a.The copper sheets that form the skin of the Statue of Liberty have acquired a greenish coating over the years. b.Carbon appears as black powder. c.Adding food coloring to water. d.Wood burns in air.