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Pre AP Chemistry
Chapter 9 Practice Set
Show your work for all problems.
Exercise 1
For questions 1-4 use the equation:
4NH3 + 6NO  5N2 + 6H2O
1. Calculate the moles of NH3 required to react with 15.0 moles of NO.
2. Calculate the moles of nitrogen produced from 7.5 moles of NO.
3. Calculate the moles of NO required to produce 0.65 moles of nitrogen.
4. Calculate the moles of water produced from 11.2 moles of NO.
5. Calculate the number of moles of oxygen needed for the complete combustion of 5.00
moles of vitamin C.
C6H8O6 + 5O2  6CO2 + 4H2O
6. A sample of 0.2500 moles of solid potassium chlorate is heated gently for a period of
time and 0.2000 moles of the compound decomposes. Calculate the number of moles of
oxygen gas that is produced.
KClO3  KCl + O2
7. How many moles of oxygen are required to burn 4.8 moles of butane?
2C4H10 + 13O2  8CO2 + 10H2O
8. Sodium chloride (0.400 mol) is allowed to react with an excess of sulfuric acid. How
many moles of hydrogen chloride could be formed?
NaCl + H2SO4  Na2SO4 + HCl
9. If 0.380 mol of barium nitrate is allowed to react with an excess of phosphoric acid,
how many moles of barium phosphate could be formed?
Ba(NO3)2 + H3PO4  Ba3(PO4)2 + HNO3
10. How many moles of hydrogen molecules could be produced by the reaction of 3.40
moles of sodium atoms with water?
Na + H2O  NaOH + H2
11. How many moles of HI would be necessary to produce 2.20 moles of iodine,
according to the following balanced equation?
10HI + 2KMnO4 + 3H2SO4  5I2 + 2MnSO4 + K2SO4 + 8H2O
12. V2O5 + Cl2  VOCl3 + O2
a. How many moles of V2O5 are required to produce 7.0 moles of VOCl3?
b. How many moles of O2 are produced from 5.0 moles of V2O5
c. How many moles of Cl2 are required to produce 6.0 moles of VOCl3?
d. How many moles of V2O5 are required to produce 4.0 moles of O2?
Exercise 2
For questions 1-14 use the equation:
2Mg + O2  2MgO
1. Calculate the number of moles of oxygen needed to react with 6.00 moles of Mg.
2. Calculate the number of moles of MgO produced when 0.4 moles of oxygen react.
3. Calculate the number of moles of MgO produced when 32 g of oxygen react.
4. Calculate the grams of oxygen needed to produce 6 g of MgO.
For questions 5-9 use the equation:
2C6H6 + 15O2  12CO2 + 6H2O
5. Calculate the number of moles of oxygen required to react with 5.00 moles of C6H6.
6. Calculate the moles of CO2 produced when 0.75 moles of O2 react.
7. Calculate the number of grams of C6H6 needed to produce 50.0 g of water.
8. Calculate the number of moles of water produced when 75 g of oxygen react.
9. Calculate the grams of C6H6 needed to produce 25 g of CO2.
10. Calculate the number of grams of H2SO4 produced when 27 g of water react with an
excess of SO3.
H2O + SO3  H2SO4
11. Calculate the number of molecules of oxygen produced when 34.0 g of water
decomposes.
12. How many molecules of chlorine are produced when 40.0 g of salt is split by
electrolysis?
13. Calculate the mass of copper that is formed when 15.0 g of aluminum reacts with
excess copper (II) sulfate.
14. Calculate the number of grams of oxygen that can be produced by completely
decomposing 15 g of mercury (II) oxide.
15. Calculate the number of grams of carbon dioxide produced from the burning of 1.65
moles of C3H8.
C3H8 + 5O2  3CO2 + 4H2O
16. Calculate the number of grams of zinc chloride that can be prepared from 34.0 g of
zinc.
Zn + 2HCl  ZnCl2 + H2
17. Calculate the number of grams of hydrogen that can be produced from 6.80 g of
aluminum.
2Al + 6NaOH  2Na2AlO2 + 3H2
18. How many grams of silver chloride can be prepared from 78.0 g of silver nitrate?
AgNO3 + NaCl  AgCl + HNO3
19. If 4.00 g of Bi react with an excess of F2, determine the yield of BiF3.
3Bi + 3F2  2BiF3
20. Calculate the number of moles of barium sulfate that can be prepared from 60.0 g of
barium chloride.
BaCl2 + Na2SO4  BaSO4 + NaCl
21. Calculate the number of moles of calcium chloride that would be necessary to prepare
85.0 g of calcium phosphate.
CaCl2 + Na3PO4  Ca3(PO4)2 + NaCl
22. How many grams of chlorine gas must be reacted with excess sodium iodide if 10.0
grams of sodium chloride are needed?
23. What mass of copper is required to replace silver from 4.00 g of silver nitrate?
24. How much silver phosphate is produced if 10.0 g of silver acetate react with excess
sodium phosphate?
25. If excess ammonium sulfate reacts with 20.0 g of calcium hydroxide, how many
grams of ammonia are produced? The other products are water and calcium sulfate.
Exercise 3
1. Given the following balanced equation:
H2 + F2  H2F2 + 5.27 x 105 J
Calculate the number of joules of heat energy produced in the reaction of 37.0 g of
fluorine gas with sufficient hydrogen gas.
2. Given the following balanced equation:
O2 + 2F2 + 4.60 x 104 J 2OF2
Calculate the number of grams of fluorine gas needed for the reaction with 8.74 x 103 J of
heat energy and sufficient oxygen gas.
3. The overall reaction in commercial heat packs can be represented as
4Fe + 3O2  2Fe2O3 + 1,652 kJ
How much heat is released when 1.00 g of iron is reacted with excess oxygen?
4. Consider the combustion of propane:
C3H8 + 5O2  3CO2 + 4H2O + 2,221 kJ
Assume that all the heat comes from the combustion of propane. What mass of propane
must be burned to furnish this amount of energy assuming the process is 60.% efficient?
5. Consider the following reaction:
2Mg + O2  2MgO + 1,204 kJ
How many grams of MgO are produced when 96.0 kJ of heat are produced?
Exercise 4
1. Suppose a 2.00 g sample of potassium chlorate is heated and 0.35 g of oxygen was
collected as a result of the decomposition. What is the % yield of the reaction?
2KClO3  2KCl + 3O2
2. Calculate the percent yield in the electrolytic decomposition of hydrogen chloride if
25.8 g of HCl produce 13.6 g of chlorine gas.
2HCl  H2 + Cl2
3. Calculate the actual yield for the production of ammonia gas from hydrogen and
nitrogen gases if the percent yield is 68.2% and you begin with 2.00 kg of nitrogen gas.
N2 + 3H2  2NH3
4. Calculate the percent yield when 24.8 g of C3H8 are burned in air to produce 15.0 g of
water vapor.
C3H8 + 5O2  3CO2 + 4H2O
5. What is the actual amount of magnesium oxide that can be produced when carbon
dioxide reacts with 42.8 g of magnesium metal? The percent yield for this reaction is
81.7%.
2Mg + CO2  2MgO + C
6. The percentage yield of a reaction is 73.7%. How many grams of Al must be used to
react with an excess of H3PO4 to give 30.0 g of AlPO4?
7. Freon-12, CCl2F2, is prepared by CCl4 reacting with HF. HCl is the other product of
this reaction. What is the percent yield of a reaction in which 12.5 g of CCl2F2 is
produced from 32.9 g of CCl4?
8. Chlorobenzene, C6H5Cl, is manufactured on a large scale to produce such useful
compounds as aspirin, oil of wintergreen, insecticides, and disinfectants. A particular
industrial reactor produced chlorobenzene by this reaction in 73.0% yield. What mass of
benzene, in kg, would be required to produce 775 kg of chlorobenzene?
C6H6 + Cl2  C6H5Cl + HCl
9. Calculate the percent yield if 125 g of NaClO3 were heated and produced 50.0 g of
NaCl.
2NaClO3  2NaCl + 3O2
10. Suppose 50.0 g of TiO2 is reacted with excess chlorine and carbon and 55.0 g of TiCl4
is obtained. Compute the percentage yield of TiCl4.
TiO2 + 2Cl2 + 2C  TiCl4 + 2CO
11. Ethyl propionate has a pineapple-like odor and is used as a flavoring agent in fruit
syrup. In an experiment 349 g of ethyl propionate was obtained from 250. g of ethanol,
with propionic acid in excess. Calculate the percentage yield of this reaction.
C2H5OH + C2H5CO2H  C2H5O2CC2H5 + H2O
12. When 9.00 g of Al react with an excess of H3PO4, 30.0 g of AlPO4 are produced.
What is the percent yield of this reaction?
2Al + 2H3PO4  2AlPO4 + 3H2
13. How many grams of C2H2 is produced if 2.0 g of hydrogen gas reacts with carbon
that results in a 92.0% yield?
2C + H2  C2H2
14. What mass of ammonium chloride is produced if 5.00 g of ammonia reacts with
excess hydrochloric acid with a 95.0% yield?
NH3 + HCl  NH4Cl
Exercise 5
1. Aluminum combines with iodine according to the following equation. How many
grams of AlI3 can be formed when 1.00 g of aluminum reacts with 12.00 g of iodine?
2Al + 3I2  2AlI3
2. Zinc and sulfur react to for zinc sulfide, a substance used in phosphors that coat the
inner surface of TV tubes. How many grams of ZnS can be formed when 12.0 g of Zn
react with 6.50 g of S?
Zn + S  ZnS
3. What mass of PbI2 will precipitate when 2.57 g Pb(NO3)2 react with 2.28 g of KI?
Pb(NO3)2 + 2KI  PbI2 + 2KNO3
4. The mass of iron produced by the reaction of 7.00 kg of Fe2O3 and 3.00 kg of CO is
3.55 kg. What is the percent yield?
Fe2O3 + 3CO  2Fe + 3CO2
5. The mass of H2 produced by reaction of 1.60 g Fe and 2.00 g HCl is 0.0505 g. What is
the percent yield?
Fe + 2HCl  FeCl2 + H2
6. The mass of H2 produced by reaction of 1.80 g Al and 6.00 g H2SO4 is 0.112 g. What
is the percent yield?
2Al + 3H2SO4  Al2(SO4)3 + 3 H2
7. How many kilograms of potassium nitrate will be produced from 50.0 kg of potassium
chloride and 50.0 kg of nitric acid? An important by-product is chlorine. How many
kilograms of chlorine will be produced?
4KCl + 4HNO3 + O2  4KNO3 + 2Cl2 + 2H2O
8. Suppose that 60.0 g of sodium hydroxide is added to 20.0 g of sulfuric acid. How
many grams of sodium sulfate will be produced?
2NaOH + H2SO4  Na2SO4 + 2H2O
Exercise 6
1. Calculate the amount of excess reagent when 3.1 mol of SO2 react with 2.7 mol of
oxygen.
2SO2 + O2  2SO3
2. What is the limiting reagent when 100 g of H3PO4 react with 25.0 g Al?
3. Calculate the moles of excess reagent when 4.0 moles of CH4 react with 4.00 mol of
O2.
CH4 + 2O2  CO2 + 2H2O
225 g of zinc reacts with 275 g of H2SO4 to produce 1.50 g of hydrogen.
Zn + H2SO4  ZnSO4 + H2
4. Identify the excess reagent.
5. Identify the limiting reagent.
6. What is the theoretical yield of hydrogen?
7. What is the actual yield of hydrogen?
8. What is the amount of zinc at the end of the reaction?
9. What is the amount of sulfuric acid at the end of the reaction?
10. What is the percent yield of the reaction?
170.0 g of NH3 reacts with 300.0 g of NaClO to produce 105 g of N2H4.
2NH3 + NaClO  N2H4 + H2O + NaCl
11. Identify the excess reagent.
12. Identify the limiting reagent.
13. What is the theoretical yield of N2H4?
14. What is the actual yield of N2H4?
15. What is the percent yield of N2H4?
16. How much NH3 will remain at the end of the reaction?
17. How much NaClO will remain at the end of the reaction?
18. Cupric sulfide (0.610 mol) is treated with 1.40 mol of nitric acid. (a) How many
moles of cupric nitrate could be produced? (b) If 0.500 mol of cupric nitrate is actually
obtained, what is the percent yield? (c) Calculate the number of moles of excess reagent
remaining at the end of the reaction.
3CuS + 8HNO3  3Cu(NO3)2 + 2NO + 4H2O + 3S
19. A 1.4 g sample of magnesium is treated with 8.3 g of sulfuric acid. (a) How many
grams of hydrogen could be produced? (b) If 0.060 g of hydrogen is actually obtained,
what is the percent yield? (c) Calculate the number of moles of excess reagent remaining
at the end of the reaction.
Mg + H2SO4  MgSO4 + H2
20. Iron (II) hydroxide (3.20 mol) is treated with 0.270 mol of H3PO4. (a) How many
grams of iron (II) phosphate could be produced? (b) If 34.0 g of iron (II) phosphate is
actually obtained, what is the percent yield? (c) Calculate the number of moles of excess
reagent remaining at the end of the reaction.
3Fe(OH)2 + 2H3PO4  Fe3(PO4)2 + 6H2O