1. Practice Problem
If 10.0 g if sodium peroxide, Na2O2 , reacts with water to
produce sodium hydroxide and oxygen, how many liters of
oxygen will be produced at 20. oC and 750. torr?
P1V1 = P2V2
T T2
PV = nRT
1 atm = 760 torr
R = atm*L / mol*K
2 Na2O2 (s) + 2 H2O (l) → 4 NaOH (aq) + O2 (g)

2. 2 Na2O2 (s) + 2 H2O (l) → 4 NaOH (aq) + O2 (g)
10.0 g Na2O2 (1mol) = mol Na2O2
(78.0g)
0.128 mol Na2O2 (1 mol O2) = mol O2
(2 mol Na2O2)
P1V1 = P2V2
T T2
PV = nRT

3. PV = nRT
P = 750
760
V = nRT = mol O2 ( atm L / mol K) 293 K
P atm
V = 1.56 L

4. P1V1 = P2V2
T T2
mol O2 (22.4 L) = L STP
(1 mol)
760 torr L = torr V V = 1.56 L
273K K

5. 1 C3H8 (g) + 5 O2 (g) → 3 CO2 (g) + 4 H2O (g)
Practice Problem
1 C3H8 (g) + 5 O2 (g) → 3 CO2 (g) + 4 H2O (g)
What volume of oxygen will react with 15.0 L of propane (C3H8)
to form carbon dioxide and water?
What volume of carbon dioxide will be formed?
What volume of water vapor will be formed?
All the components are gases so the mole ratios = volume ratios
when the gases are at the same pressure and temperature.

6. 1 C3H O2 → 3 CO H2O
1 C3H L C3H8 X = 75.0 L O2
5 O = X L O2
1 C3H L C3H X = 45.0 L CO2
3 CO2 = X L CO2
1 C3H L C3H X = L H2O
4 H2O = X L H2O

7. Do Problems: 38 & 40 pg 461
42 & 44 pg 463