Chapter 7 Problem Set
Reaction Stoichiometry- Balance Reactions First
1. In the reaction shown, what mass of iron is needed
to react completely with 64.0 grams of sulfur? Fe +
S  FeS (111 g)
2. When zinc reacts with sulfuric acid (H2SO4), what
mass of hydrogen is produced from 318 grams of
zinc? Zn + H2SO4  ZnSO4 + H2 (9.73 g)
3. How much copper(I)chloride can be produced
beginning with 75.0 grams of copper(I)oxide?
Cu2O + HCl  CuCl + H2O (104 g)
4. How much nitric acid (HNO3) is needed to react
completely with 25.0 grams of magnesium?
Mg + HNO3  Mg(NO3)2 + H2 (131 g)
5. How many grams of hydrogen sulfide is produced
from the reaction of 50.0 grams of iron(II)sulfide
and excess HCl?
FeS + HCl  FeCl2 + H2S (19.4 g)
6. How many grams of aluminum bromide can be
formed from the reaction of 4.00 moles of
ammonium bromide? (356 g)
Al2(SO4)3 + NH4Br  AlBr3 + (NH4)2SO4
7. How many grams of Gallium oxide can be produced
from the reaction of 12.0 grams of gallium? Ga +
O2  Ga2O3 (16.1 g)
8. How many grams of water are formed from the
complete combustion of 25.0 grams of C3H8?
C3H8 + O2  CO2 + H2O (40.9 g)
9. How many grams of oxygen are formed from the
decomposition of 50.0 grams of NaClO3?
NaClO3  NaCl + O2 (22.5 g)
10. How many grams of oxygen are needed to produce
2.00 grams of P2O5? O2 + P4  P2O5) (1.13)
11. How many grams of chlorine are needed to react
with 16.7 grams of iron metal in the following
reaction? Fe + Cl2  FeCl3 (31.9 g)
12. How many grams of aluminum are needed to form
exactly 135 grams of aluminum oxide?
Al + O2  Al2O3 (71.4 g)
Stoichiometry- You write the reaction
1. When hot water reacts with iron metal, hydrogen gas
(H2) and Iron(III)oxide are formed. What mass of
water is needed to react completely with 100.0
grams of iron? (48.4 g)
2. When aluminum metal is heated in oxygen (O2),
aluminum oxide is produced. What mass of
aluminum oxide can be produced from 25.0 grams
of aluminum? (47.2 g)
3. When ammonia (NH3) is burned in oxygen (O2),
nitrogen gas (N2) and water are produced. How
many grams of ammonia are needed to react with
3.00 grams of water? (3.78 g)
4. How many grams of copper metal can be produced
from the reaction of copper(I)nitrate and 30.0 grams
5.
6.
7.
8.
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10.
of iron metal. The products of the reaction are
copper metal and iron(II)nitrate. (68.3 g)
What mass of chlorine gas (Cl2) is needed to react
with 85.8 grams of potassium iodide? The products
of the reaction are potassium chloride and iodine
(I2). (18.3 g)
Potassium hydroxide reacts with sulfuric acid
(H2SO4) to form water and potassium sulfate. How
many grams of potassium sulfate can be produced if
you start with 150.0 grams of sulfuric acid? (267 g)
How many grams of nitrogen gas (N2) are needed to
react with 38.7 grams of hydrogen (H2) to produce
NH3? (181 g)
How many moles of chlorine (Cl2) are needed to
react with excess antimony metal to produce 58.9
grams of anitmony trichloride? (0.687 moles)
When iron metal rusts, it reacts with oxygen (O2) to
form iron(III)oxide, the brown rust. If you have 20.8
grams of iron(III)oxide, how many grams of iron
rusted? (14.5 g)
Carbon dioxide reacts with graphite (C) to form
carbon monoxide. How many grams of carbon
monoxide can be formed from the reaction of 50.0
grams of carbon dioxide? (63.8 g)
Limiting Reactant Problems
1. Based on the balanced equation, calculate the mass
of CO2 produced when 2.80 C4H8 moles and 22.8
O2 moles react. (493)
C4H8 + 6O2  4CO2 + 4H2O
2. A 50.6 g sample of Mg(OH)2 is reacted with 45.0 g
of HCl according to the reaction:
Mg(OH)2 + 2 HCl  MgCl2 + 2 H2O
Calculate the theoretical yield (maximum mass ) of
MgCl2 that can be produced. (58.6 g)
3. A 2.00 g sample of ammonia, NH3, is mixed with
4.00 g of oxygen.
4 NH3 + 5 O2  4NO + 6 H2O
a. Calculate how much NO can be produced (3.00
g)
b. Calculate the mass of the excess reactant that
remains. (0.30 g NH3)
4. 90.0 g of FeCl3 reacts with 52.0 g of H2S.
FeCl3 + H2S  HCl + Fe2S3
a. What is the mass of HCl produced? (60.8 g)
b. What mass of excess reactant remains after the
reaction? (23.6 g)
5. In an experiment, 3.25 g of NH3 are allowed to react
with 3.50 g of O2.
NH3 + O2
NO + H2O
a. How many grams of NO are formed? (2.63 g)
b. How much of the excess reactant remains after
the reaction? (1.76 g NH3)
6. 4.95 g of ethylene (C2H4) are combusted with 3.25 g
of oxygen.
a. What is the limiting reagent? (O2)
b. How many grams of CO2 are formed? (2.98 g
CO2)
7. Consider the reaction:
2Al + 3I2 2AlI3
a. Calculate the mass of AlI3 that can be formed
from the reaction of 1.20 g aluminum and 2.40 g
iodine. (2.57 g)
b. How many grams of Al are left over in part b?
(1.03 g)
8. 15.00 g aluminum sulfide and 10.00 g water react
until the limiting reagent is used up. Here is the
balanced equation for the reaction:
Al2S3 + 6 H2O  2Al(OH)3 + 3 H2S
a. What is the maximum mass of H2S which can
be formed from these reagents? (9.48g)
b. How much excess reagent remains after the
reaction is complete? (1.13 g)
9. If there are 35.0 grams of C6H10 and 45.0 grams of
O2, how many grams of the excess reagent will
remain after the following reaction? (6.40 g)
6 C6H10 + 17 O2  12 CO2 + 10 H2O
Percent Yield
1. What is the percent yield of the following
reaction if 60 grams of CaCO3 is heated to give
15 grams of CaO? (44.6%)
CaCO3  CaO + CO2
2.
For the balanced equation shown below, if the
reaction of 40.8 grams of C6H6O3 produces a
39.0% yield of H2O, how many grams of H2O
would be produced? (6.83 g)
C6H6O3 + 6O2  6CO2 + 3H2O
3. For the balanced equation shown below, if the
reaction of 20.7 grams of CaCO3 produces 6.81
grams of CaO, what is the percent yield? (58.7
%)
CaCO3  CaO+CO2
4. For the balanced equation shown below, if the
reaction of 91.3 grams of C3H6 produces a
81.3% yield, how many grams of CO2 would be
produced? (232 g)
2C3H6 + 9O2  6CO2 + 6H2O
5. For the balanced equation shown below, if the
reaction of 0.112 grams of H2 produces 0.745
grams of H2O, what is the percent yield?
(74.5%)
Fe3O4 + 4H2  3Fe + 4H2O
6. For the balanced equation shown below, if the
reaction of 77.0 grams of CaCN2 produces 27.1
grams of NH3, what is the percent yield? (83 %)
CaCN2 + 3H2O  CaCO3 + 2NH3
Molarity
1. What is the molarity of a solution made by
dissolving 75.5 g of C6H12O6 in enough water to
make 450.0 ml of solution? (0.926 M)
2. How many grams of sodium sulfate are contained in
1.50 L of a 0.25 M solution? (53.3 g)
3. How many milliters of 0.98 M H2SO4 are needed to
provide 0.0024 moles? (2.45 mL)
4. What is the molarity of a solution made by
dissolving 2.65 g of NaCl in enough water to make
40.0 ml of solution? (1.13 M)
5. How many grams of AgNO3 are contained in 500.0
mL of a 0.25 M solution? (21.2 g)
6. How many milliteres of 0.078 M NaOH are needed
to provide 0.54 grams of NaOH? (173 mL)
7. What is the molarity of a solution made by
dissolving 20.8 g of C12H22O11 in enough water to
make 275 mL of solution? (0.280 M)
8. How many milliters of 0.100 M NaOH are needed to
provide 0.00345 moles? (34.5 mL)
9. What is the molarity of a solution made by
dissolving 20.0 g of NaOH in enough water to make
2.4 liters of solution? (0.142 M)
10. How many milliters of 0.98 M H2SO4 are needed to
provide 0.788 grams of H2SO4? (8.20 mL)
11. How many milliters of 1.3 M HCl are needed to
provide 0.0389 moles? (29.9 mL)
12. What is the molarity of a solution made by
dissolving 7.80 g of KOH in enough water to make
1.50 liters of solution? (0.0927 M)
13. How many milliters of 0.14 M HCl are needed to
provide 0.0054 moles of HCl? (39 mL)
14. Which contains more molecules per liter, a 0.050 M
solution of glycerine, C3H8O3 or 0.050 M glucose,
C6H12O6? (Same)
Writing Directions for Preparing Solutions
1. How would you prepare 40.0 mL of 2.00 M RbF2
from the solid? (Mass 9.88 g, dissolve in small volume,
dilute to 1 L)
2. How would you prepare 750.0 mL of 0.020 M
KSCN from the solid? (Mass 1.85 g, dissolve in
small volume, dilute to 750 mL )
3. How would you prepare 17.0 mL of 0.10 M CaCl2
from the solid? (Mass 0.189 g, dissolve in small
volume, dilute to 17 mL)
4. How would you prepare 600.0 mL of 0.100 M Na2S
from the solid? (Mass 4.69 g, dissolve in small
volume, dilute to 600 mL)
5. How would you prepare 500.0 mL of 0.10 M
(NH4)2CO3 from the solid? (Mass 4.80 g, dissolve in
small volume, dilute to 500 mL)
6. How would you prepare 1.00 L of 0.130 M NaOH
from the solid? (Mass 5.20 g, dissolve in small
volume, dilute to 1 L)
7. How would you prepare 850.0 mL of 0.110 M
C12H22O11 from the solid? (Mass 32.0 g, dissolve in
small volume, dilute to 850 mL)
8. How would you prepare 500.0 mL of 0.110 M
Ba(NO3)2 from the solid? (Mass 14.4 g, dissolve in
small volume, dilute to 500 mL)
9. How would you prepare 250.0 mL of 0.220 M CaCl2
from the solid? (Mass 6.11 g, dissolve in small
volume, dilute to 250 mL )
10. How would you prepare 100.0 mL of 0.155 M
Na2SO4 from the solid? (Mass 2.20 g, dissolve in
small volume, dilute to 100 mL)
Dilution Problems
1. A chemist starts with 50.0 mL of a 0.40 M NaCl
solution and dilutes it to 1000. mL. What is the
concentration of NaCl in the new solution? (0.020
M)
2. A chemist wants to make 500. mL of 0.050 M HCl
by diluting a 6.0 M HCl solution. How much of that
solution should be used? (4.2 mL)
3. How much 2.0 M NaCl solution would you need to
make 250 mL of 0.15 M NaCl solution? (19 mL)
4. What would be the concentration of a solution made
by diluting 45.0 mL of 4.2 M KOH to 250 mL?
(0.76 M)
5. What would be the concentration of a solution made
by adding 250 mL of water to 45.0 mL of 4.2 M
KOH? (0.64 M)
6. How much 0.20 M glucose solution can be made
from 50. mL of 0.50 M glucose solution? (125 mL)