Pure Substances
 A sample of matter that has definite chemical
and physical properties.
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Pure Substances
 A sample of matter that has definite chemical
and physical properties.
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Elements
 pure substance that cannot be separated into
simpler substance by physical or chemical
means.
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Elements
 pure substance that cannot be separated into
simpler substance by physical or chemical
means.
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Compounds
Pure substance composed of two or more
different elements joined by chemical
bonds.
 Made of elements in a specific ratio
that is always the same
 Has a chemical formula
 Can only be separated by
chemical means, not physically
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Compounds
Pure substance composed of two or more
different elements joined by chemical
bonds.
 Made of elements in a specific ratio
that is always the same
 Has a chemical formula
 Can only be separated by
chemical means, not physically
Wednesday, January 9, 13
Mixtures
 A combination of two or more pure




substances that are not chemically
combined.
substances held together by physical forces,
not chemical
No chemical change takes place
Each item retains its properties
in the mixture
They can be separated physically
Chem4kids.com
Wednesday, January 9, 13
Mixtures
 A combination of two or more pure




substances that are not chemically
combined.
substances held together by physical forces,
not chemical
No chemical change takes place
Each item retains its properties
in the mixture
They can be separated physically
Chem4kids.com
Wednesday, January 9, 13
Mixtures vs. Compounds
http://www.bbc.co.uk/schools/ks3bitesize/science/chemistry/elements_com_mix_6.shtml
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Can you identify the following?
You will be shown a series of photos. Tell if
each photo represents an item composed of
an element, compound, or mixture.
Review:
 An element contains just one type of atom.
 A compound contains two or more different
atoms joined together.
 A mixture contains two or more different
substances that are only physically joined
together, not chemically.
 A mixture can contain both elements and
compounds.
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Element, Compound, or Mixture?
Rocks
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Element, Compound, or Mixture?
Rocks
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Element, Compound, or
Mixture?
Copper
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Element, Compound, or
Mixture?
Copper
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Element, Compound, or
Mixture?
Copper
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Element, Compound, or
Mixture?
Jelly Beans
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Element, Compound, or
Mixture?
Jelly Beans
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Element, Compound, or
Mixture?
Table Sugar
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Element, Compound, or
Mixture?
Table Sugar
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Element, Compound, or
Mixture?
Table Sugar
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Element, Compound, or
Mixture?
Diamond
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Element, Compound, or
Mixture?
Diamond
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Element, Compound, or
Mixture?
Diamond
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Element, Compound, or
Mixture?
Tea
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Element, Compound, or
Mixture?
Tea
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Element, Compound, or
Mixture?
Salt
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Element, Compound, or
Mixture?
Salt
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Element, Compound, or
Mixture?
Salt
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Element, Compound, or
Mixture?
Neon Gas
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Element, Compound, or
Mixture?
Neon Gas
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Element, Compound, or
Mixture?
Neon Gas
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Element, Compound, or
Mixture?
Salad
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Element, Compound, or
Mixture?
Salad
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Element, Compound, or
Mixture?
Pure Water
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Element, Compound, or
Mixture?
Pure Water
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Element, Compound, or
Mixture?
Pure Water
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Element, Compound, or
Mixture?
Aluminum
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Element, Compound, or
Mixture?
Aluminum
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Element, Compound, or
Mixture?
Aluminum
Wednesday, January 9, 13
Element, Compound, or
Mixture?
Lemonade
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Element, Compound, or
Mixture?
Lemonade
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Element, Compound, or
Mixture?
Silver
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Element, Compound, or
Mixture?
Silver
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Element, Compound, or
Mixture?
Silver
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Element, Compound, or
Mixture?
Sand
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Element, Compound, or
Mixture?
Sand
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Heterogeneous Mixtures
Type of matter
consisting of at least
two parts physically
combined
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Visible parts (phases)
Varying composition
Impure
Physically separable
Heterogeneous Mixture Examples
Dirt
Heterogeneous mixtures
have more than one
visible phase
Concrete
Car
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Homogeneous Mixtures
Matter that is uniform
throughout
Referred to as a
Solution
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•
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1 visible part (uniform
distribution)
Constant composition
throughout
Even distribution of
particles
Solution (Homogeneous Mixture)
Examples
Salt water
Brass
(A solution of metals=alloy)
Glass
Solutions appear to be one
part, but are actually just
mixed very well
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