1. Balancing Chemical Reactions Why?

2. There are laws!!!! Matter cannot be created or destroyed only changed. So if you start with 20 hydrogen, you end up with 20 hydrogen

3. Equations Vinegar + Baking Soda White Powder + Clear Liquid + Bubbles Reactants Products HC 2 H 3 O 2 + NaHCO 3 NaC 2 H 3 O 2 + H 2 O + CO 2 Word Equation Formula Equation

4. Balancing a Formula HC 2 H 3 O 2 + NaHCO 3 NaC 2 H 3 O 2 + H 2 O + CO 2 HCCHHHOO + NaHCOOONaCCHHHOO + HHO + COO (5H, 3C, 5O, Na) 14 atoms (5H, 3C, 5O, Na) 14 atoms

5. Balanced? Ag + H 2 S Ag 2 S + H 2 Ag, 2H, S2Ag, 2H, S Ag + H 2 S Ag + H 2 S Ag 2 S + H 2 2Ag, 2H, S If not….The ONLY thing you can do is multiply the number of MOLECULES you have. You do this by putting a coefficient in front of the MOLECULE. 2 The 2 multiplies everything after it until you have a different molecule.

6. Balance the following 2Na + 2H 2 O  2NaOH + H 2 2Na + 2H 2 O  2NaOH + H 2 Na=Na= H =H = O = O = H 2 O + O 2  H 2 O 2 H 2 O + O 2  H 2 O 2 H =H = O = O = 2 4 2 4 2 2 BALANCED 2 3 2 2 So what do we need to do? 2 4 4 2 4 4 BALANCED Step 1: list all the elements underneath the reactants and products Step 2: Count how many atoms of each element are on the reactant side and the product side Step 1: list all the elements underneath the reactants and products Step 2: Count how many atoms of each element are on the reactant side and the product side 3 rd Step: Put numbers (coefficients) in front of the compounds that you are short on to multiply all of the atoms in the compound. When you do that, you may have to change other ones as well.

7. CaCl 2  2Ca + Cl 2 Ca=Ca= Cl =Cl = 2Al + 6NaOH  2Na 3 AlO 3 + H 2 Al=Al= Na=Na = O =O = H =H = 2 1 2 2 4 2 4 2 2 6 2 6 6 6 2 2 6 3 6 BALANCED

8. Now you do some at your desk Zn + HCl  ZnCl 2 + H 2 Al + 3O 2  Al 2 O Al + 3O 2  Al 2 O

9. 1.Zn + 2HCl  ZnCl 2 + H 2 2.12Al + 3O 2  6Al 2 O