Chapter 9 Homework
1. Consider the general chemical equation: A + 2 B  3 C
a) How many moles of C are produced from 1 mol of A?
3 moles
b) How many liters of gas B must react to give 3 L of gas C, at STP?
2L
c) If 1.50 g of A reacts with 1.65 g of B, what is the mass of C produced?
3.15 g
2. Verify the conservation of mass law using the molar masses of reactants and products for
each substance in the following balanced equations:
a) 2 N2(g) + O2(g)  2 N2O (g)
56 g + 32 g  88 g √
b) P4(s) + 5 O2(g)  2 P2O5(s)
123.88 g + 160 g  283.88 g
√
3. Given the decomposition of hydrogen peroxide, calculate the moles of oxygen gas
produced from 5.00 mol of H2O2.
2 H2O2(l)  2 H2O(l) + O2(g)
2.50 mol oxygen
4. How many moles of propane gas, C3H8, react with 2.50 mol of oxygen gas? How many
moles of carbon dioxide are produced?
C3H8(g) + 5 O2(g)  3 CO2(g) + 4 H2O(g)
0.500 mol oxygen; 1.50 mol carbon dioxide
5. Given the balanced equation, calculate the following (mass-mass):
2 Bi(s) + 3 Cl2(g)  2 BiCl3(s)
a) mass of BiCl3 that can be prepared from 3.45 g of bismuth, Bi
5.21 g
b) mass of chlorine gas, Cl2, that must react to give 3.52 g of BiCl3
1.19 g
6. Given the balanced equation, calculate the following (mass-volume):
2 HgO(s)  2 Hg(l) + O2(g)
a) milliters of oxygen gas released from decomposing 2.50 g of HgO
129 mL
b) grams of HgO required to produced 75.0 mL of oxygen gas
1.45 g
7. Given the balanced equation, calculate the following (under constant conditions)
(volume-volume):
2 SO2(g) + O2(g)  2 SO3(g)
a) volume of sulfur trioxide gas produced from 25.0 L of oxygen gas
50.0 L
b) volume of sulfur dioxide gas required to produce 10.5 L of sulfur trioxide gas
10.5 L
8. If 5.00 moles of hydrogen gas and 5.00 moles of oxygen gas are combined, what is the
limiting reactant?
2 H2(g) + O2(g)  2 H2O(l)
hydrogen is the limiting reactant
9. Complete the following table (2 parts, a, b) for the reaction of cobalt and sulfur by
calculating the moles of Co, S, and CoS after reaction according to the balanced equation:
Co(s) + S(s)  CoS(s)
Experiment
(a) before reaction
after reaction
(b) before reaction
after reaction
mol Co
1.00
0.00
2.00
0.00
mol S
1.00
0.00
3.00
1.00
mol CoS
0.00
1.00
0.00
2.00
10. A 1.50-g sample of sodium nitrate is decomposed by heating. If the resulting sodium
nitrite has a mass of 1.29 g and the calculated yield is 1.22 g, what is the percent yield?
106 %