Basic Concepts in Chemistry

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Basic Concepts in Chemistry
2

• chemical
• any substance that takes part in,
• or occurs as a result of,
• a chemical reaction
• All matter can be considered to be
• chemicals or mixtures of chemicals.

3

• chemical reaction
• a rearrangement of atoms such that
• what you end up with products
• differs from
• what you started with reactants

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Combustion of a Hydrocarbon
carbon dioxide
methane oxygen ?
water


H2O(g)
O2(g)
CO2(g)
CH4(g)

?
2
2
?
5
sodium hydroxide
water
sodium
hydrogen

?

NaOH(aq)
Na(s)
H2O(l)
H2(g)
2
2
2

?

?
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Law of Conservation of Mass

• total mass total mass
• of reactants of products
• Rmass Pmass

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Black Snake Demonstration
Click for Video
The Law of Conservation of Mass total mass of
reactants total mass of products
H2SO4
Sugar
Dehydration of sugar with the addition of
sulfuric acid.
During chemical reactions, no measurable change
in total mass occurs.
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Basic Concepts in Chemistry
sodium water ? hydrogen sodium hydroxide
2 Na(s) 2 H2O(l) ? H2(g) 2
NaOH(s)
Lets visualize whats happening at the particle
level
What happens to the particles during a chemical
reaction?
They are NOT created or destroyed they are
merely rearranged
Is there a change in energy associated with a
chemical change?
Yes heat, light, sound - perhaps not easily
noticed
9
Basic Concepts in Chemistry
sodium water ? hydrogen sodium hydroxide
2 Na(s) 2 H2O(l) ? H2(g) 2
NaOH(s)
Lets visualize whats happening at the particle
level
What happens to the particles during a chemical
reaction?
They are NOT created or destroyed they are
merely rearranged
Is there a change in energy associated with a
chemical change?
Yes heat, light, sound - perhaps not easily
noticed
10

• Synthesis
• taking small molecules and putting them
• together, usually in many steps, to make
• something more complex

Sunlight
Oxygen
Carbon Dioxide
Glucose
Water
Photosynthesis
CO2 H2O O2 C6H12O6
11
World of ChemistryThe Annenberg Film Series
VIDEO ON DEMAND
Episode 3 - Measurement The Foundation of
Chemistry
Accuracy and precision are fundamental properties
to modern chemistry. The distinction between
the two terms and their importance in
establishing measurement standards in commerce
and science are explained. (Running
Time 2838)