9/17/09
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
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9/17/09
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“The ability of a substance to undergo a chemical
change that transforms it into another substance”
Examples:
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When a substance is changed / converted into a
new substance or substances.
Examples:
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Combustion (fire, explosions)
Monday’s Lab
Reactant A + Reactant B  Products To determine a chemical property a chemical
reaction must be attempted / performed.
Example:
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Combustible (it burns)
Oxidizer (it rusts)
Reducer (it causes rust)
Corrosive (it “eats” through other substances)
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?
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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)
Precipitates: Cu(NO3)2 + NaOH, Pb(NO3)2 + KI
Heat, Light Emission, Gas: Glycerin and Potassium
Permanganate
Color Change, Gas, and Heat: Sugar and Sulfuric
Acid.
Gas Production: Baking Soda and HCl.
A property of a substance that can be measured
with out changing the identity of the substance.
Example:
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How tall is it?
How much does it weigh?
Boiling Point?
Freezing Point?
Water changes from a liquid to a gas at 100o C.
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Boiling Point
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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)
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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