Stoichiometry Test Review—Chemistry 215 (Chapter 11 in text) Name ______
3. The carbon dioxide exhaled by astronauts can be removed from a spacecraft by reacting it with lithium hydroxide to form lithium carbonate and water. An average person exhales about 20 moles of CO2 per day. How many moles of lithium hydroxide would be required to maintain two astronauts in a spacecraft for three days?
4. Write and balance the following equation and answer the questions below.
Potassium chlorate decomposes to form potassium chloride and oxygen.
a. How many moles of oxygenare produced from 10 moles of Potassium chlorate?
b. How many moles of potassium chloride are produced using 3 moles of Potassium chlorate?
c. How many moles of Potassium chlorateare needed to produce 50 moles of oxygen?
d. Calculate how many liters of oxygen are produced by the reaction.
5. Calculate the mass of sodium chloride produced when 5.50 moles of sodium reacts in excess chlorine gas.
6. How many grams of chlorine gas must be reacted with excess sodium iodide to produce 6.00 moles of sodium chloride? Write the complete balanced chemical reaction and calculate the answer. How many liters of chlorine gas are needed?
7. Calculate the mass of hydrochloric acid (HCl) needed to react with 5.00 moles of zinc.
a. Write and balance the chemical reaction.
b. Perform the calculation.
8. Balance each equation and solve the problem.
a.If 40.0 g of magnesium reacts with excess hydrochloric acid, how many grams of magnesium chloride are produced?
b.b. Determine the mass of copper needed to react completely with a solution containing 12.0 g of silver nitrate.
c. How many grams of hydrogen chloride are produced when 15.0 g of sodium chloride reacts with excess sulfuric acid? Write a balanced chemical equation first.
d. What is the theoretical yield of silver phosphate produced if 30.0 g of silver acetate reacts with excess sodium phosphate. Write a balanced chemical equation first.
11.3 Limiting Reactants
9. Ammonia (NH3) is one of the most common chemicals produced in the United States. It is used to make fertilizer and other products. Ammonia is produced by the reaction of nitrogen gas with hydrogen gas.
a. If you have 1.00 x 103g of nitrogen gas and 2.50 x 103g of hydrogen gas, which is the limiting reactant in the reaction?
b. How many grams of ammonia can be produced from the amount of limiting reactant available?
c. Calculate the mass of excess reactant that remains after the reaction is complete.
d. How many liters of ammonia can be produced from 2.50 x 103g of hydrogen gas?
10. Aluminum reacts with chlorine to produce aluminum chloride.
a. Balance and write the chemical equation.
b. If you begin with 3.2 g of aluminum and 5.4 g of chlorine, which is the limiting reactant?
c. How many grams of aluminum chloride can be produced from the amount of limiting reactant available?
d. Calculate the mass of excess reactant that remains after the reaction is complete.
Percent Yield
11. Calculate the percent yield for each chemical reaction based on the data provided.
a. theoretical yield: 25 g; actual yield: 20 g
b. theoretical yield: 55 g; actual yield: 42 g
c. theoretical yield: 5.2 g; actual yield: 4.9 g
12. Calculate the actual yield for each chemical reaction based on the data provided.
a. theoretical yield: 20 g; percent yield: 95%
b. theoretical yield: 75 g; percent yield: 88%
c. theoretical yield: 9.2 g; percent yield: 62%
Chapter 11 Review
14. What is stoichiometry?
15. Write two questions that stoichiometry can help you answer about the following chemical equation.
4HCl(aq) + O2(g) 2H2O(l) + 2Cl2(g)
16. Relate the law of conservation of mass to stoichiometry.
17. What is the difference between a limiting reactant and an excess reactant?
Answers:
3. 240 mol LiOH is needed.
4. 2KClO3(s) 2KCl(s) + 3O2(g)
a. 15 mol O2
b. 3 mol KCl
c. 33 mol KClO3, or 30 mol KClO3 using significant figures
d. 336 L O2
5. From the reaction 2Na(s) + Cl2(g) 2NaCl(s), 321 g NaCl is produced.
6. a. 2NaI(aq) + Cl2(g) 2NaCl(aq) + I2(s)
b. 213 g Cl2
67.2 L Cl2
7. a. Zn(s) + 2HCl(aq) ZnCl2(aq) + H2(g)
b. 365 g HCl
8. a. Mg(s) + 2HCl(aq) MgCl2(aq) + H2(g); 157 g MgCl2
b. Cu(s) +2AgNO3(aq) Cu(NO3)2(aq) + 2Ag(s);
2.24 g Cu
c. 2NaCl(aq) + H2SO4(aq) Na2SO4 + 2HCl(g); 9.36 g HCl
d. 3AgCH3COO(aq) + Na3PO4(aq) Ag3PO4(s) +3NaCH3COO(aq); 25.1 g Ag3PO4
9. a. N2
b. 1.22 x 103 g NH3
c. 34 g H2
d. 1.85 x 10 4 L NH3
10. a. 2Al(s) + 3Cl2(g) 2AlCl3(s)
b. Cl2
c. 6.8 g AlCl3
d. 1.8 g Al
11. a. 80%
b. 76%
c. 94%
12. a. 19 g
b. 66 g
c. 5.7 g
13. theoretical yield: 39.2 g; percent yield: 75.3%
14. Stoichiometry is the study of quantitative relationships between amounts of reactants used and products formed by a chemical reaction.
15. Sample questions: What mass of HCl is needed to react completely with a known mass of O2? How much water will be produced if a given mass of HCl is used in the reaction?
16. The law of conservation of mass states that matter is neither created nor destroyed; thus, in a chemical reaction, the mass of the reactants must equal the mass of the products.
17. The limiting reactant limits the amount of product that can form from the reaction. An excess reactant is left over after the reaction is complete and all of the limiting reactant has been used up.