Stoichiometry Review
1. How many grams of CO are needed to react with an excess of Fe O to produce 209.7 g Fe?
Fe O (s) + 3CO(g)
3CO (g) + 2Fe(s)
2. A 500-g sample of Al (SO ) is reacted with 450 g of Ca(OH) . A total of 596 g of CaSO
is
produced. What is the limiting reagent in this reaction, and how many moles of excess reagent are
unreacted?
Al (SO ) (aq) + 3Ca(OH) (aq)
2Al(OH) (s) + 3CaSO (s)
3. Consider the following reaction:
2H S(g) + 3O (g)
2SO (g) + 2H O(g)
If O was the excess reagent, 8.3 mol of H S were consumed, and 137.1 g of water were collected
after the reaction has gone to completion, what is the percent yield of the reaction?
4. When a mixture of sulfur and metallic silver is heated, silver sulfide is produced. What mass of
silver sulfide is produced from a mixture of 3.0 g Ag and 3.0 g S ?
16Ag(s) + S (s)
8Ag S(s)
5. If a total of 13.5 mol of NaHCO and 4.5 mol of C H O react, how many moles of CO and Na
C H O will be produced?
3NaHCO (aq) + C H O (aq)
3CO (g) + 3H O(s) +Na C H O (aq)
6. Metallic copper is formed when aluminum reacts with copper(II) sulfate. How many grams of
metallic copper can be obtained when 54.0 g of Al react with 319 g of CuSO ?
Al + 3CuSO
Al (SO ) + 3Cu
7. How many grams of beryllium are needed to produce 36.0 g of hydrogen? (Assume an excess of
water.)
Be(s) + 2H O(l)
Be(OH) (aq) + H (g)
8. If 5.0 g of H are reacted with excess CO, how many grams of CH OH are produced, based on a
yield of 86%?
CO(g) + 2H (g)
CH OH(l)
9. How many grams of chromium are needed to react with an excess of CuSO to produce 27.0 g Cu?
2Cr(s) + 3CuSO (aq)
Cr (SO ) (aq) + 3Cu(s)
10. If 8.6 g of H reacted with 4.3 g of O at STP, what is the mass of the gaseous water collected
(assuming that none of it condenses)?
2H (g) + O (g)
2H O(g)