Chapter 17

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Chapter 17 Classification of Matter
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17.1 Composition of Matter
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SUBSTANCE
An Element
or
A Compound
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SUBSTANCE

• Elements contain atoms that are all alike

• Compounds have 2 or more elements in fixed
  proportion

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Mixtures
2 or more substances can be separated by PHYSICAL
means to form a MIXTURE
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Types of Mixtures

• Heterogeneous
• Mixture of different and easily distinguishable
  materials

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Types of Mixtures

• Homogeneous
• Mixture containing 2 or more gaseous, liquid or
  solids blended evenly
• Also a solution

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Types of Mixtures

• Colloids
• Heterogeneous mixture
• Particles never settle

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Tyndall Effect

• Scattering of light by particles in a colloid.
• You can see a light beam as it passes through the
  colloid.

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Types of Mixtures

• Suspensions
• Heterogeneous mixture
• Visible particles settle

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17.2 Properties of Matter
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Physical Property characteristic that does not
change a substances identity

• Color
• Shape
• Size
• Melting point
• Boiling point

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Appearance physical description
How would you describe a pumpkin or cranberry
juice?
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Behavior how a substance acts
Magnetism
Viscosity
Ductility
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Using physical properties to separate mixtures
Iron/Wood use a magnet or density. Wood will
float in water
Gold Sifter
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Chromatography separating substances based on
various chemical charges Picture pigments in
plants
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Physical Change change in size, shape, or
state not in identity
Ex Freezing or Melting
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Distillation used to separate a mixture
Distillation tower at an oil refinery
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Chemical Property characteristics that indicate
if a substance can undergo a chemical change

• Flammability
• Light sensitivity

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Chemical Change a new substance is formed
Temperature change, smell, bubble formation, rust
formation
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Chemical changes can be used to separate
substances, mostly in industry.
Cleaning tarnish and separating metals from their
ores are example.
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Weathering of Earths surface includes physical
and chemical changes.

• Physical
• Big rocks ? small rocks
• Streams carry particles to other locations

• Chemical
• Acid rain

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Law of Conservation of Mass Mass before change
Mass after change Mass of Reactants Mass of
Products
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Some of the logs components combine with oxygen
to form gases.
When wood burns, ashes remain. How the mass is
conserved?