Chapter 2 Matter and Change

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Chapter 2Matter and Change

• Chemistry pg. 38

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2.1 Properties of Matter

• Properties used to describe matter are classified
  as
• 1. Extensive depends on the amount of
• matter in a sample
• ex. Mass, volume
• 2. Intensive depends on the type of
  matter
• in a sample, not the amount
• ex. Color, hardness, boiling
  point

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Substance

• Matter that has a uniform and definite
  composition
• ex. Gold, copper (pure substances)
• Every sample has identical intensive properties
  because every sample has the same composition

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Physical Property

• A quality or condition of a substance that can be
  observed or measured without changing the
  substances composition
• Help chemists identify substances
• Hardness
• Color
• Conductivity
• Malleability
• (see Table 2.1, Pg. 40)

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Three states of matter

• Solid-definite shape, volume, not easily
  compressed
• Liquid-indefinite shape, flows, definite volume,
  almost incompressible
• Gas-indefinite shape, indefinite volume, easily
  compressed
• http//www.chem.purdue.edu/gchelp/liquids/characte
  r.html

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Physical Changes

• Properties of a material change but the
  composition does not
• ex. Boil, freeze, melt, condense
• AND
• break, split, grind, cut, crush
• Physical changes can be
• REVERSIBLE or IRREVERSIBLE

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2.2 Mixtures

• Physical blend of 2 or more components
• ex. Chicken noodle soup, air
• Mixtures can be classified as
• HETEROGENOUS or HOMOGENOUS
• (based on distribution of components)

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Matter can be Heterogeneous

• The composition is not uniform throughout
• More than one phaseso its a mixture
• -Phase any region with a uniform set of
  properties that can be separated from each other
  by definite boundaries called interfaces

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Matter can be Homogeneous

• The composition is uniform throughout, evenly
  distributed
• Only one phase

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Identify the following

• Concrete __________________________
• Vinegar____________________________
• Carbon dioxide_____________________
• Granite rock________________________
• Milk________________________________

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Separating mixtures

• Distillation - a liquid is boiled to produce a
  vapor which is condensed into a liquid
• Other ways?
• distillation
• How to perform simple distillation in the
  chemistry lab Wonder How To

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2.3 Elements and Compounds

• Substances classified as
• 1. __________- simplest form of matter
  that has a unique set of properties (O, H)
• 2. ___________- substance that contains 2
  or
• more elements chemically combined
  in a
• fixed proportion (C6H12O6)

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• Compounds can be broken down by
• ______________ means.
• Elements cannot be broken down
• Chemical change produces matter with a different
  composition than the original matter
• Sugar Carbon Water

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Properties of Compounds

• Generally, properties of compounds are different
  from their component elements
• Sodium - soft, gray metal, reacts with oxygen
• Chlorine - yellow-green poisonous gas
• Sodium chloride
• Reaction

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Distinguishing Substances and Mixtures

• If the composition of a material is fixed, the
  material is a substance
• examples?
• If the composition of a material may vary, the
  material is a mixture
• examples?

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Classifying Matter
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• Classify the following materials as an element,
  compound, or mixture.
• a. Table salt
• b. Salt water
• c. Sodium

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Symbols and Formulas

• Chemical symbols elements
• O, C, Na, Ne
• Chemical formulas compounds
• CO2 , H2O

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2.4 Chemical Reactions

• Chemical Property the ability of a substance to
  undergo a specific chemical change (describes the
  way a substance may react to form other
  substances)
• examples?
• - can be observed only when a substance
• undergoes a chemical change

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• Fig. 2.13 (pg. 53)
• Chemical reaction S Fe
• physical - composition of matter never changes
• chemical composition of matter always
• changes
• Chemical change chemical reaction
• Reactants
  Products

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• Chemical change chemical reaction
• (one or more substances change into
  one
• or more new substances)
• Reactants Products

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Recognizing Chemical Changes

• 4 Ways
• 1. Color change
• 2. Formation of precipitate
• 3. Production of gas
• 4. Transfer of energy

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• Precipitate
• an insoluble substance that forms in, and
  separates from, a solution

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Identify clues for chemical changes

• magnesium ribbon in flame
• Sodium iodide solution added to mercury(II)
  chloride solution

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Law of Conservation of Mass

• In any physical change or chemical reaction, mass
  is __conserved______________.
• mass of products mass of reactants