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Unit 2 Matter and Change. Chemistry I Mr. Patel SWHS. Topic Outline. 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)
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Unit 2Matter and Change Chemistry I Mr. Patel SWHS
Topic Outline 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)
Properties of Matter Remember matter is anything that has mass and occupies volume. Matter is described using properties that are extensive or intensive properties.
Extensive 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 Properties • 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
Classify the statement as Intensive or Extensive • The Boiling point of water is 100OC. • The mass if 300 kg. • The length is 30 m. • The density of water is 1.0 g/mL. • Intensive • Extensive • Extensive • Intensive
Substance All matter can be divided into substances and mixtures Substance – uniform and definite composition Every sample of a substance has identical intensive properties. Why?
CopperKettle Gold Sculpture
MatterAnything that has mass and volume SubstanceConstant Composition; All particles identicalEx: Water, Helium MixtureVariable Composition; 2 or more substancesEx: Sand, Soil Physically Separate
Substances • 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
MatterAnything that has mass and volume SubstanceConstant Composition; All particles identicalEx: Water, Helium MixtureVariable Composition; 2 or more substancesEx: Sand, Soil Physically Separate ElementMade up of identical atoms; on Periodic TableEx: Zinc, Uranium CompoundMade up of 2 or more elements; combined chemicallyEx: Carbon dioxide Chemically Separate
Mixtures • 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 Mixtures can be separated physically Filtration – solid from liquid Distillation – liquid from liquid or solid
MatterAnything that has mass and volume SubstanceConstant Composition; All particles identicalEx: Water, Helium MixtureVariable Composition; 2 or more substancesEx: Sand, Soil Physically Separate ElementMade up of identical atoms; on Periodic TableEx: Zinc, Uranium CompoundMade up of 2 or more elements; combined chemicallyEx: Carbon dioxide HeterogeneousUneven Distribution; easy to separateEx: Vegetable Soup HomogenousUniform Distribution; called solutionEx: Tap water, Steel Chemically Separate
Physical Changes and Properties • 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 and Properties • Physical Changes do not involve chemical reactions • No Breaking or Forming Chemical Bonds • Substance is the same before and after the change
Chemical Changes & Properties • 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
Signs of Chemical Changes • Clues for a chemical reaction: • Transfer of Energy – heat, sound, light • Color Change • Gas Production • Formation of Precipitate – solid that settles out of a liquid mixture • Don’t confuse for a physical change
Conservation of Mass 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
Classify: Physical or Chemical Change • Burning Gasoline • Evaporation of Water • Stripping a Copper Wire • Mold Growing on Yogurt • Alka-Setlzer tablets • Chemical • Physical • Physical • Chemical • Chemical
Molecular Forces INterMolecular Forces Intramolecular 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