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MIXTURES_ ELEMENTS_ COMPOUNDS AND SOLUTIONS

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					MIXTURES, ELEMENTS,
  COMPOUNDS AND
     SOLUTIONS
      CHEMISTRY
      MS. ZIMMER
         2005
     CLASSES OF MATTER
• Matter exists as mixtures,
  solutions, elements or
  compounds
• Classified by their make up
• Not classified by their phases,
  because several can exist in
  more than one phase.
   CLASSES OF MATTER REVIEW
• What are the four classes of matter?
  – Mixtures, solutions, compounds, elements
• How are the classes classified?
  – They are classified by their make up.
• Why isn’t matter classified by their
  phases?
  – They are not classified by their phases
    because some matter can exist in more
    than one phase.
            MIXTURES
• Mixtures consists of
  two or more
  substances
• Mixture are not
  chemically
  combined
• Each substance in a
  mixture maintains its
  physical properties
    PROPERTIES OF MIXTURES
• Substances in a mixture are not
  chemically combined.
  – Sugar dissolved in water is still sugar
• Substances may change in physical
  appearance, but the chemical
  properties do not.
  – You can’t see the sugar in the water
    but it is there.
  PROPERTIES OF MIXTURES CONT.
• Substances in a mixture can be
  present in any amount.
  – There can be a little sugar or a lot of
    sugar dissolved in the water.
• Substances in a mixture can be
  separated by physical means.
  – Dissolve water and you have the
    sugar left.
  – No chemical reaction needed to
    separate mixtures
   HETEROGENEOUS MIXTURE
• “least-mixed”
• Particles are large
  enough to see
• Does not appear the
  same throughout
• Easy to separate the
  particles
• Not only solid-solid
  mixtures
• Can be liquid-liquid
HOMOGENEOUS MIXTURES
       • “Well-mixed”
       • Particles are small
         and not easily
         recognizable
       • Do not settle when
         the mixture stands
       • Particles are mixed
       • Appears to be the
         same throughout
COLLOIDS
• Particles are mixed
  together but are not
  dissolved
• Particles are large and
  kept suspended
• Particles will not separate
  when left standing
• Bombarded by other
  particles
   – Often appears cloudy
             SOLUTIONS
• Homogeneous mixture
  formed when one
  substance dissolves into
  another.
• Solutions have a
  substance that is
  dissolved called the
  solute
• Solutions have a
  substance that does the
  dissolving called a solvent
       SOLUTIONS CONT.
• Particles in a solution
  are not visible
• Hard to separate
  physically
• Solutions appear to
  be clear
• Particles are evenly
  spread out
         SOLUBILITY

• A substance that dissolves
  in water is soluble
   –Salt, sugar
• A substance that can’t
  dissolve in water is insoluble
   –Mercury, oil
       SOLUBILITY CONT.
   SOLUBILITY OF          SOLUBILITY OF
         SOLIDS                  GASES
• As the temperature •    As the
  of a solvent            temperature
  increases, the          increases, the
  solubility of the       solubility of the
  solute increases        gas decreases
   – More sugar can        – The warmer the
     dissolve in warm        soda, the less
     water than in cold      “fizz” due to less
     water                   CO2 in solution
               ALLOYS
• Metal solutions
• Solids dissolved
  in solids
• Gold jewelry is a
  solid solution of
  gold and brass
• Brass is a
  solution of
  copper and zinc
                 REVIEW
• What is a mixture?
   – A combination of 2 or more substances
     mixed together but not chemically
     combined
• How does a heterogeneous mixture differ
  from a homogeneous mixture?
   – Heterogeneous mixtures have large
     particles and do not appear the same
     throughout
   – Homogeneous mixtures have small
     particles that are well blended and are
     the same throughout.
             Review Cont.
• What is a colloid?
  – A homogeneous mixture where the
    particles are mixed together but are not
    dissolved and are permanently
    suspended
• What is a solution?
  – A type of homogeneous mixture formed
    when one substance dissolves in another
    substance.
• What are the two parts of a solution?
  – Solute (what dissolves) and solvent (what
    does the dissolving)
               Review Cont.
• What are two properties of a solution
  – The particles are not easily separated
  – Particles are so small they are not visible
• What is solubility?
  – The ability to absorb in water
• What is an alloy? Give an example.
  – A metal solution of two or more metals.
  – Gold jewelry, brass, stainless steel

				
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