1. Balancing Chemical Reactions

2. Law of Conservation of Mass
Why is this important???
We need to balance equations!!!
States that in any chemical reaction, the mass (matter) can never be created nor destroyed. The mass of the reactants are the same as the mass of the products.
Antoine Lavoisier

3. Balancing Equations
If the following is the equation for producing a hot dog: Bu8 + Hd6  BuHd + 3 4 24
Law of Conservation of Mass says matter cannot be created nor destroyed; so …

4. Rules:
1. Choose an element to begin with. LEAVE H’s and O’s until the end.
2. Balance element on both sides of equation with coefficients (#’s in front of molecule/atom) by multiplying coefficients by subscripts.
3. Repeat with another element until all elements are balanced. (no fractions allowed)
4. Make lowest term by reducing if necessary.
5. Check to make sure it is balanced. Use a table to help if needed

5. 4 4 2 2 2 2 Example 1 O O O H2 + O2  H2O # of Reactants # of Products
Hydrogen Atoms
Oxygen Atoms 4 4 2 2

6. + H2 Ca + 2 HCl CaCl2 1 1 2 2 2 2 Example 2 # of Reactants
# of Products
Calcium Atoms
Hydrogen Atoms
Chloride Atoms 1 1 2 2 2 2

7. 2 Al + 2 3 Cl2 AlCl3 2 2 6 6 Example 3 # of Reactants # of Products
Aluminum Atoms
Chlorine Atoms 2 2 6 6

8. Example 4

9. Try some on your own:
Practice Sheet