S320 Honors Chemistry
Homework Set #6: Stoichiometry
Remember to balance chemical equations and report answers with appropriate significant
figures!
1. How many grams of H2O will be formed when 32.0 g H2 is allowed to react with excess
O2 according to the equation:
H2
+
O2 →
H2O
286g of H2O
2. Calculate the number of moles of nitrogen dioxide (NO2) produced when 3.0 moles of
oxygen are produced in the decomposition of nitric acid by light?
HNO3 →
NO2 +
H2O +
O2
12 moles NO2
3. Calculate the number of moles of Na2CS3 produced from 0.60 moles of CS2 by
the following reaction.
CS2 +
NaOH →
Na2CS3 +
Na2CO3 +
H2O
0.40 mol Na2CS3
4. How many moles of NO can be produced from 0.680 g of NH3 according to
the following reaction?
NH3 +
O2 →
0.0399 mol NO produced
NO +
H2O
5. How many molecules of H2O2 are required to react with 11.0 g of N2H4 according to the
following reaction?
H2O2 + N2H4 →
HNO3
+
H2O
14.5 x 1023 molecules H2O2
6. How many moles of iodine are produced when 7.00 moles of chlorine reacts with
an excess of sodium iodide?
NaI +
Cl2 →
NaCl + I2
7.00 mol I2
7. A chemist uses hot hydrogen gas to convert chromium(III) oxide to pure chromium.
How many moles of hydrogen are needed to convert 250 grams of chromium(III)
oxide?
Cr2O3 +
H2 →
Cr +
H2O
4.9 mol H2
8. Calculate the mass of hydrogen formed when 27 g of aluminum reacts with excess
hydrochloric acid according to the balanced equation below.
Al +
HCl →
3.0g H2
AlCl3 +
H2
9. In a small-scale experiment, 29.3 g of silver nitrate in solution is reacted with excess
copper wire:
AgNO3 +
Cu →
Cu(NO3)2 +
Ag
How much copper (II) nitrate can theoretically be formed in this reaction?
16.2g Cu(NO3)2
10. Mercury (I) carbonate will break down when exposed to heat:
Hg2CO3 →
Hg2O +CO2
How much product will be formed when 2.50 g of reactant is decomposed?
2.26g Hg2O
11. Tetraphosphorus decoxide combines with water to form phosphoric acid in the following
chemical equation:
P4O10 + H2O → H3PO4
In order to form 100.0 g phosphoric acid, how much tetraphosphorus decoxide will you
need?
72.42g P4O10
12. When placed in lead (II) sulfate solution, magnesium reacts to form magnesium sulfate
and lead. How much lead (II) sulfate would be required to react with 327.0 g
magnesium?
Write the balanced equation and complete the math.
4079g Lead (II) sulfate
13. Like most alkali metals, potassium reacts with water to form basic potassium hydroxide
and hydrogen gas:
K+
H2O → KOH + H2
How much hydrogen gas will be formed by reacting 125 g potassium with excess water?
3.22g H2
14. Nitric acid can be neutralized by any base to form a salt and water, as in the following
equation:
Mg(OH)2 +
HNO3 → Mg(NO3)2 + H2O
How much magnesium nitrate salt will be formed by the reaction of 250. g magnesium
hydroxide with 250. g nitric acid?
294g magnesium nitrate
15. How many grams of titanium (IV) oxide can be produced when 80 g of TiCl4 reacts with
20 g O2 as shown in the following equation?
TiCl4 (s) +
O2 (g) →
TiO2 (s) +
Cl2 (g)
30g TiO2
16. When 150 g of benzene, C6H6, reacts with 25.0 g of oxygen gas it produces carbon
dioxide and water.
a. Write a balanced chemical reaction.
b. Find the number of moles of each reactant.
c. If only 20 g of carbon dioxide is formed, what is the amount of benzene that you’ll
have left?
1.9 moles C6H6, 0.78 moles O2, 132g benzene remaining
17.
H3PO4 +
NaOH →
Na3PO4 +
H2O
How much 0.20 M H3PO4 is needed to react with 100 mL of 0.10 M NaOH?
17mL
18.
HCl +
Zn →
ZnCl2 +
H2
When you use 25 ml. of 4.0 M HCl to produce H2 gas, how many grams of zinc does it
react with?
3.3g Zn
19.
Fe +
Au(NO3)3 →
Fe(NO3)2 +
Au
Throwing some scrap iron in a gold nitrate solution causes the gold metal to precipitate.
How much 0.50 M gold nitrate solution would react with 224 grams of iron metal?
5.3L Au(NO3)3 solution