Honors Chemistry Chapter 2

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Honors Chemistry Chapter 2

• Matter and Change

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• Matter anything that has mass and takes up
  space
• Mass- amount of matter an object contains
• Materials differ in type of matter they are
  composed of

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The Properties of Matter

• Extensive properties depend on the amount of
  matter that is present
• Example volume, mass, amount of energy in the
  substance
• Intensive properties do not depend on the
  amount of matter that is present
• Example melting point, boiling point, density

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• Substance matter that is uniform and has a
  definite composition
• All samples of an identical substance have the
  identical physical and chemical properties
• Physical property quality or condition of a
  substance that can be observed or measured
  without changing the substances composition

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Properties of Matter
When a substance undergoes a physical change, its
physical appearance changes. Ice melts a solid
is converted into a liquid. Physical changes DO
NOT result in a change of composition.
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Examples of Physical Properties

• Color
• Odor
• Hardness
• Density
• Solubility
• Melting point, boiling point, freezing point
• Physical state solid, liquid, gas

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• Page 40 Table 2.1 Physical properties of some
  substances

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States of matter

• Solid (s)
• Liquid (l)
• Gas (g)
• Plasma we dont deal with

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Classification of Matter

• States of Matter
• Matter can be a gas, a liquid, or a solid.
• Gases have no fixed shape or volume.
• Gases can be compressed to form liquids.
• Liquids have no shape, but they do have a volume.
• Solids are rigid and have a definite shape and
  volume.

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Gas and vapor not the same

• Gas normally exists that way at room
  temperature
• Vapor gas state of a substance that is normally
  a liquid or solid at room temperature

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Physical change

• A change which alters a material without changing
  its composition
• Cutting, grinding, melting, boiling, freezing,
  dissolving

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Mixtures

• Physical blend of two or more substances
• Composition can vary
• 2 types
• Heterogeneous
• Homogeneous

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Heterogeneous Mixture

• Not uniform in composition
• Has 2 or more phases
• Phase any part of a system with uniform
  composition and properties
• Dirt, salad, paper, rocky road ice cream

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Homogeneous Mixture

• Has a completely uniform composition
• All components are evenly distributed
• Consists of a single phase
• Called a SOLUTION

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Solution what do you think of?

• Can be gas, liquid, or solid!!!!!

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Separating mixtures

• Use PHYSICAL methods
• Magnet, sifting,
• Liquid mixtures distillation Page 47
• Page 47 11-17

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Substances

• Can be elements or compounds
• Element definition
• Compound 2 or more elements that have been
  CHEMICALLY combined.
• Can only be separated by CHEMICAL means

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• Sugar heat? carbon water
• Water electric current ? hydrogen
• 
  oxygen

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Properties of compounds

• MUCH DIFFERENT THAN THE PROPERTIES OF THE
  ELEMENTS FROM WHICH THEY ARE COMPOSED!!!!!
• NaCl

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• Flow chart Pg. 50
• Elements ? represented by symbols
• Compounds ? represented by formulas
• Pg. 52 Table 2.2

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Chemical Change

• A change that produces matter with a different
  composition than the original matter

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Properties of Matter
When a substance changes its composition, it
undergoes a chemical change When pure hydrogen
and pure oxygen react completely, they form pure
water.
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Is iron transforming into rust a physical or
chemical change

1. Physical
2. Chemical

Does the substance change composition or just
change appearance?
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The color of sulfur is yellow..

1. Physical
2. Chemical

Does the substance change composition or just
change appearance?
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Dynamite explodes to form a mixture of gases

1. Physical
2. Chemical

Does the substance change composition or just
change appearance?
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Aluminum melts at 933 K

1. Physical
2. Chemical

Does the substance change composition or just
change appearance?
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Plants use CO2 to make sugar

1. Physical
2. Chemical

Does the substance change composition or just
change appearance?
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Chemical Reactions

• One or more substances change into new substances
• REACTANT(S) ? PRODUCT(S)
• ? means change into, produce, yields

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Chemical Property

• The ability of a substance to undergo chemical
  reactions and to form new substances
• Rusting, burning, fermenting, exploding, rotting,
  decomposing
• Iron and sulfur example

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Indications that a chemical reaction has occurred

• Energy released or absorbed
• Color change
• Odor released
• Production of a gas
• irreversibility

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Law of Conservation of Mass

• During any chemical reaction, the mass of the
  products is always equal to the mass of the
  reactants.