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Matter:

Matter:. It’s what the world’s made of. Chemistry Studies Matter- Branches of Chemistry. Organic Study of most carbon-containing compounds Basis for most life processes as well as plastics, drugs, petrochemicals, food, etc. Inorganic Study of non-organic substances Physical

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Matter:

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  1. Matter: It’s what the world’s made of.

  2. Chemistry Studies Matter- Branches of Chemistry • Organic • Study of most carbon-containing compounds • Basis for most life processes as well as plastics, drugs, petrochemicals, food, etc. • Inorganic • Study of non-organic substances • Physical • Study of properties and changes of matter and their relation to energy • Analytical- identification of the components and composition of materials • Biochemistry- study of substances and processes occurring in living things • Theoretical- use of math and computers to provide theories that explain chemical observations; predict properties of new compounds

  3. Chemistry Studies Properties • Extensive properties • depend on amount of matter present • volume, mass, and amount of energy present • Intensive properties • independent of the amount present • boiling point, melting point, density, conducting electricity and energy, phase change energy and others

  4. States of Matter • Solid – Definite shape and volume • Liquid – Definite volume but variable shape • Assumes the shape of its container • Gas – Neither definite shape or volume • Expands to fill any size container • Takes the shape of the container • Plasma – Extremely high energy state where electrons have been ejected

  5. Changes of State • Melting • Freezing • Vaporizing • Boiling- change from liquid to vapor within the liquid as well as at the surface • Evaporation- change from liquid to gas at the surface of the liquid; occurs at much lower temperatures than boiling • Condensing • Sublimation- example: dry ice (CO2) • Deposition- example: frost forming on a cold surface

  6. What is Matter made of? • Elements • Compounds • Mixtures See classification scheme for matter on p.11 of the text

  7. What is Matter made of? • Elements-cannot be broken down • Atomic-most elements can exist as individual atoms(smallest particle of any element). Examples: Fe, Au, Ag, Al • Molecular-some elements are… • Diatomic H2, O2, N2, F2, Cl2, Br2, I2 • Triatomic O3 • Tetratomic P4 • Octatomic S8 • Elements are found on Periodic Table

  8. What is Matter made of? • Compounds-Two or more elements chemically bonded together • These can be broken down into smaller compounds or elemental parts • Examples: CaCO3(chalk), Fe2O3(rust) • Smallest particle is a Molecule

  9. Pure Substances • Always have a fixed composition • Can be elements or compounds • Always have the same properties • Always have the same composition • Pure water is always 11.2% Hydrogen and 88.8% Oxygen by mass

  10. What is Matter made of? • Mixtures-These are made of two or more chemicals that are not chemically bonded together. Examples: Sand, Salt/Pepper, Milk, Blood, Muddy water • Homogeneous – uniform throughout • Heterogeneous – differences are found • Mixtures can often be separated easily by physical means such as filtration, distillation or chromatography.

  11. Filtration: Separates solid substances from liquids and solutions. Coffee Filters Some water filters Pool filters using sand or DE- diatomaceous earth (spongy skeleton)

  12. Distillation: Separates Homogeneous mixtures using the differences in boiling points. BPH20 = 100˚C BPNaCl = 808˚C Water vapor rises first and condenses in the tube.

  13. Chromatography: Separates substances on the basis of differences in solubility in a solvent.

  14. Classification Flowchart

  15. Physical Properties • Observed without changing the identity of a substance • Volume, mass, size, color, shape, smell, hardness, density, texture, melting & boiling points, temperature…

  16. Physical Changes • Change that alters appearance or form of material but does not change the identity of the substance • Examples: tearing paper, breaking pencil, ice melting • Phase changes are ALWAYS Physical Changes

  17. Chemical Properties • What are the chemical activities of the material • Does it react with Oxygen • Does it react with Water • Does it react with Chlorine • Does it react with Fluorine • Does it react with …

  18. Chemical Changes • A chemical reaction occurs that produces NEW substances • Old chemicals bonds(Reactants) must be broken and new ones(Products) formed usually with energy exchanging • Example: burning fuel, digesting food, Photosynthesis, rusting iron, plant decay

  19. 2 Kinds of Chemical Reactions • Exothermic • Releases heat into surroundings • Might feel warm or hot to the touch • Reactants have higher energy in their bonds • Examples: • Mixing acid with bases • Burning of a fuel • Digestion

  20. 2 Kinds of Chemical Reactions • Endothermic • Absorbs heat from the surroundings • Could feel cool to the touch • Products have more energy than reactants • Examples: • Cooking an egg • Dissolving Baking Soda • Photosynthesis • Cooking coffee beans

  21. Chemical Equations • 2 H2(g) +O2(g)  2 H2O(l) + Energy • Coefficients •  “yields” • (s), (g), (l) • Energy is always involved-Heat or Light • Exothermic • Endothermic • Balancing will follow later • Matter CANNOT be created or destroyed but it can be changed in reactions

  22. Measuring Matter • Using Le Système International (SI)(Metric System only)(see pg 34) • Volume -- V=LxWxH V=Pr2h V=4/3Pr3 • Mass -- gram, Kilogram- not affected by gravity, based on quantity of matter • Weight -- Pounds, Ounces- caused by the pull of gravity which can change • Volume – Gallons, Liters- space that a substance takes up • Density = mass/volume

  23. Measurements are wrong! • Measurements are not pure numbers • Measurements are made by man using instruments made by man and subject to error • UNCERTAINTY FACTORS 345±2ml • Every measuring device has an UF • Usually ½ of the smallest readable graduation

  24. Uncertainty in Derived Quantities • For Addition and Subtraction • Round all numbers to accuracy of the least • Do the desired math operation (A) • Add all Uncertainty Factors of each measurement used above (B) • Write as A±B

  25. Uncertainty in Derived Quantities • Multiplication and Division • Round all numbers to accuracy of the least accurate number involved • Do the desired math operation • Divide each uncertainty by its measurement. Pick the largest uncertainty from previous step • Multiply the Answer (C) times the value of B B X C = new UF • Combine B ± D (Derived answer w/ new UF)

  26. Density: Physical property of a substance Mass • Density = ---------- • Volume

  27. Density • Mass/Volume • Affects the buoyancy of material. Does it float? • Is NOT affected by size of sample • Is affected by change in temperature

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