9/2/09
If you put makeup on a pig, it is still a pig,
but a pig in a frying pan is not a pig.
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“Mass is neither created or destroyed in chemical
reactions”
Matter may change state (solid, liquid or gas) during
a reaction, but the mass remains the same.
To test this law the reaction system must be closed to
the environment.
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No gas can escape
No liquid can leak out
“The ability of a substance to undergo a chemical
change that transforms it into another substance”
Examples:
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Combustible (it burns)
Oxidizer (it rusts)
Reducer (it causes rust)
Corrosive (it “eats” through other substances)
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9/2/09
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When a substance is changed / converted into a
new substance or substances.
Examples:
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Reactant A + Reactant B  Products To determine a chemical property a chemical
reaction must be attempted / performed.
Example:
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Combustion (fire, explosions)
Friday’s Lab
The flammability of water and gasoline.
How could we test if water burns?
How could we test if gasoline burns?
How could you tell if a chemical reaction is
happening?
Unexpected or drastic change in color.
Formation of a solid (precipitate) from the
combination of two liquids.
Gas Production (bubbling or fizzing).
Odor Change
Explosion, flame, or light production.
Thermal Change (closed system)
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Precipitates: AgNO3 + NaCl, Pb(NO3)2 + KI
Heat and Gas: Glycerin and Potassium
Permanganate
Color Change, Gas, and Heat: Sugar and Sulfuric
Acid.
A property of a substance that can be measured
with out changing the identity of the substance.
Example:
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Water changes from a liquid to a gas at 100o C.
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How tall is it?
How much does it weigh?
Boiling Point?
Freezing Point?
Boiling Point
Common Physical Properties
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Boiling Point
Freezing Point
Ductility (able to be made into wire)
Malleability (able to be shaped and molded)
Conductivity (able to conduct electricity)
Changes of state 3
9/2/09
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A change of substance that does not alter the
identity of the substance.
Examples
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Boiled water is still water, it is just called steam
If you chop a piece of paper in half you still have paper.
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