1. Unit 4: Chemical Equations and Stoichiometry
LESSON PLAN:
1. DQ 2.
Balancing Equations

2. Balancing Equations reactants  products
Remember the law of conservation of mass?
When a chemical reaction occurs, no atoms are created or just destroyed – they are just rearranged
Number of each element on the left side (reactants) must equal the number of the same element on the right side (products)
reactants  products

3. Balancing Equations – The Steps!
Write the unbalanced equation
Ionic compounds: charges must add to zero
Covalent compounds: use prefixes
HOFBrINCl elements are diatomic when alone Example: hydrogen gas is written H2
Add phase if given:
Solid = (s)
Gas = (g)
Liquid = (l)
Aqueous (dissolved in water or solution) = (aq)

4. Example – Step #1 Lead (IV) sulfide solid + oxygen gas 
Write and balance the following chemical equation:
Lead (IV) sulfide solid + oxygen gas 
lead (IV) oxide solid + sulfur dioxide gas

5. Balancing Equations – The Steps!
Put coefficients in front of each substance to get the amounts on the left side = the right side
Save hydrogen for 2nd to last
Save oxygen for last
Use the smallest whole number coefficients possible

6. Example – Steps #2 and 3 Lead (IV) sulfide solid + oxygen gas 
Write and balance the following chemical equation:
Lead (IV) sulfide solid + oxygen gas 
lead (IV) oxide solid + sulfur dioxide gas

7. Balancing Equations Whiteboards
Task One:
Worksheet #1 problems 1, 3, 5, 7
Task Two:
Worksheet #2 problems 1, 3, 5
Assignment:
Worksheet #1 problems 11-15
Worksheet #2 problems 11-15

9. Balancing Equations Example #1
Now let’s balance this equation…
__PbS2 (s) + __O2 (g)  __ PbO2 (s) + __SO2 (g)

10. Balancing Equations Practice #1
Write and balance the following chemical equation:
iron metal + oxygen gas  iron (III) oxide solid

11. Balancing Equations Practice #2
Write and balance the following chemical equation:
ammonium phosphate soln. + magnesium nitrate soln.  ammonium nitrate soln. + magnesium phosphate solid