1. Chemical Equations
Reactants
Products

2. Chemical Reaction Reactants  Products chemical reaction Reactants
is the process by which one or more substances change into one or more new substances.
Reactants
the original substances in a chemical reaction.
Products
the substances that are created in a chemical reaction.
Reactants  Products

3. Chemical Reaction Versus Physical Change
chemical change
new substance forms with properties that differ from original substance
physical change
changes of state of matter

4. A chemical equation vs Word Equation
methane + oxygen  carbon dioxide + water
Chemical Equation
?CH ?O2  ?CO ?H2O

5. Equations and Reaction Information
(s) Solid
(l) Liquid
(g) Gas
(aq) Aqueous (dissolved in water)
 Yields
Reversible reactions
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6. Balancing Equations Conservation of mass
The amount and type of atoms starting a reaction must be the same as the amount and type of atoms after the reaction

7. Balancing Equations coefficient
multiplies the number of atoms of each element in the formula that follows.
H2O: 2 hydrogen atoms, 1 oxygen atom
2H2O: 4 hydrogen atoms, 2 oxygen atoms

8. Diatomic Elements
Elements that when found free in nature are 2 atoms bonded together
H2, N2, O2, F2, Cl2, Br2, and I2
Can have other subscripts when in compounds but not when alone

9. H2O + CO > C6H12O6 + O2
Na + NaNO3 ---> Na2O N2

10. Assignment
Practice Problems
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