Chemistry I Mr. Patel SWHS

 Continue to Learn Major Elements and Symbols  Properties of Matter (2,1, 2,2, 2,3)  Physical and Chemical Changes (2.1, 2.4)  Inter-/Intra-molecular Forces  States of Matter (13.2, 13.2, 13.3)  Kinetics/KMT, Phase Change (13.1, 13.4)

 Remember matter is anything that has mass and occupies volume.  Matter is described using properties that are extensive or intensive properties.

 Extensive Property – a property that depends on the amount of matter in a sample. (Changes with amount) Mass – measure of the amount of matter an object contains Volume – measure of the space taken up Other examples: energy, weight, length, area

 Intensive Property – a property that does NOT depend on the amount of matter Density – D = mass/volume matter per unit volume Other examples: hardness, melting/freezing point, concentration, viscosity

1. The Boiling point of water is 100 O C. 2. The mass if 300 kg. 3. The length is 30 m. 4. The density of water is 1.0 g/mL. 1. Intensive 2. Extensive 3. Extensive 4. Intensive

 All matter can be divided into substances and mixtures  Substance – uniform and definite composition  Every sample of a substance has identical intensive properties. Why?

Copper Kettle

Matter Anything that has mass and volume Substance Constant Composition; All particles identical Ex: Water, Helium Mixture Variable Composition; 2 or more substances Ex: Sand, Soil Physically Separate

 Substances can be classified as elements or compounds  Element – simplest form of matter with unique set of properties (all atoms same) Ex: Gold, Hydrogen, Oxygen (on periodic table)  Compound – two or more elements chemically combined in fixed ratios Ex: Water, salt, baking soda  Compounds can be chemically separated to elements

Matter Anything that has mass and volume Substance Constant Composition; All particles identical Ex: Water, Helium Mixture Variable Composition; 2 or more substances Ex: Sand, Soil Element Made up of identical atoms; on Periodic Table Ex: Zinc, Uranium Compound Made up of 2 or more elements; combined chemically Ex: Carbon dioxide Physically Separate Chemically

 Mixture – a physical blend of two or more components (substances)  Heterogeneous Mixture – the composition is not uniform throughout Ex: soil, chicken noodle soup  Homogeneous Mixture – (solution) composition is uniform throughout Ex: salt water, alloys (solid in solid)

 Mixtures can be separated physically  Filtration – solid from liquid  Distillation – liquid from liquid or solid

Steel = Iron + Carbon

Matter Anything that has mass and volume Substance Constant Composition; All particles identical Ex: Water, Helium Mixture Variable Composition; 2 or more substances Ex: Sand, Soil Element Made up of identical atoms; on Periodic Table Ex: Zinc, Uranium Compound Made up of 2 or more elements; combined chemically Ex: Carbon dioxide Physically Separate Chemically Heterogeneous Uneven Distribution; easy to separate Ex: Vegetable Soup Homogenous Uniform Distribution; called solution Ex: Tap water, Steel

 Physical Property – measured properties that do not change the nature of the sample Ex: Boiling Point, Density, Mass  Physical Change – some properties may change but the composition of the material does not change Ex: Boiling, Freezing, Cutting, Splitting Can be Reversible or Irreversible

 Physical Changes do not involve chemical reactions No Breaking or Forming Chemical Bonds Substance is the same before and after the change

 Chemical Property – the ability of a substance to undergo a chemical reaction Ex: Flammability, Combustibility, decomposition  Chemical Change – the composition of matter will always change Ex: Burning, exploding, reacting, rusting, rotting Also called a chemical reaction

 Clues for a chemical reaction: 1. Transfer of Energy – heat, sound, light 2. Color Change 3. Gas Production 4. Formation of Precipitate – solid that settles out of a liquid mixture Don’t confuse for a physical change

 Law of Conservation of Mass – mass is neither created nor destroyed; it is only transformed.  The mass before a reaction must always equal the mass after a reaction

1. Burning Gasoline 2. Evaporation of Water 3. Stripping a Copper Wire 4. Mold Growing on Yogurt 5. Alka-Setlzer tablets 1. Chemical 2. Physical 3. Physical 4. Chemical 5. Chemical

INTERMOLECULAR FORCESINTRAMOLECULAR FORCES  Forces between individual molecules  Strong by Numbers  Ex: Hydrogen Bonding, Dipole forces, Dispersion Forces  Contribute to Physical Changes  Forces within a specific, individual molecule  Very Strong  Ex: Ionic Bond, Covalent Bond, Metallic Bond  Contribute to Chemical Changes

 There are four states of matter 1. Solid 2. Liquid 3. Gas 4. Plasma  We focus mostly on the first three

 Definite Shape  Definite Volume  Incompressible  Particles tightly packed - ordered  Vibrations (Not Fluid)

 Indefinite Shape  Definite Volume  Incompressible  Particles in contact but disorderly packed  Particles flow (Fluid)

 Indefinite Shape  Indefinite Volume  Highly Compressible  Particles far apart; little contact; collisions  Particles flow (Fluid)

 Particles: Have a lot of space between them Are in rapid motion Exert Pressure = Billions of collisions Spontaneously expands

 There are 6 state/phase changes  Some change require heat (energy)  Endothermic – requires heat  Exothermic – releases heat

 Solid to Liquid  Endothermic  Particles have enough energy to begin to flow  Melting Point – temp when liquid forms

 Liquid to Solid  Exothermic  Particles have lose energy and slow down  Freezing Point – temp when Solid forms  Mpt = Fpt

 Liquid to Gas  Endothermic  Particles have enough energy to break away  Boiling Point – temp when gas forms

 Gas to Liquid  Exothermic  Particles begin to stick  Same as Bpt

 Solid to Gas  Endothermic  NO liquid stage  Ex: Dry Ice

 Gas to Solid  Exothermic  No Liquid Stage  Ex: Snowing

 The temperature at which a substance undergoes a phase change depends on the pressure.  Think about boiling an egg on top of Mt. Everest. Pressure is lower so water boils at a lower temperature meaning it will take longer to cook the egg (enough heat)

 A Phase Diagram outlines the relationship between temp and pressure.  At a specified temp and pressure, we can determine what state of matter the substance is in.

 There are two important points  Triple Point – where solid, liquid, gas coexist  Critical Point – no phase boundary exist  Each line represents two states coexisting