Chapter 4 Answers
Practice Examples
1a.
(a) 2 H3PO4(aq) + 3 CaO(s) → Ca3(PO4)2(aq) + 3 H2O(l)
(b) C3H8(g) + 5 O2(g) → 3 CO2(g) + 4 H2O(g)
1b.
(a) 4 NH3(g) + 7 O2(g) → 4 NO2(g) + 6 H2O(g)
(b) 6 NO2(g) + 8 NH3(g) → 7 N2(g) + 12 H2O(g)
2a. 4 HgS(s) + 4 CaO(s) → 3 CaS(s) + CaSO4(s) + 4 Hg(l)
2b. 2 C7H6O2S(l) + 17 O2 (g) → 14 CO2(g) + 6 H2O(l) + 2 SO2(g)
3a. 2.64 mol O2
3b. 8.63 mol Ag
4a. 5.29 g Mg 3 N 2
4b. 126 g H 2
5a. 0.710 g NH 3
5b. 3.50 g O 2 ( g )
6a. 3.34 cm3 alloy
6b. 0.79 g Cu
7a. 0.4 mg H 2 ( g )
7b. 0.15g CO 2
8a. 0.307 M
8b. 0.524 M
9a. 115g NaNO3
9b. 50.9 g Na 2SO 4 ⋅10H 2 O
10a. 0.0675 M
10b. 0.122 M
11a. 18.1 mL
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11b. 4.96 g Ag2CrO4
12a. 936g PCl 3
12b. 1.86 kg POCl3
13a. 3.8 g P4
13b. 57 g O 2 remaining
14a. (a) 30.0 g CH 2 O ; (b) 25.7 g CH2O (g); (c) 85.6 % yield .
14b. 93.7%
15a. 41.8g CO 2
15b. 69.0 g impure C6 H11OH
16a. 2.47 ×103 g HNO3
16b. Approximately 56 g of SiO2 and 30 g of KNO3 are needed.
17a. 83 wt%
17b. 19.47%
Integrative Example
A. 78.3% yield
B. 83.4 % Zn
Exercises
1a. 2 SO3 
→ 2 SO 2 + O 2
1b. Cl2 O7 + H 2 O 
→ 2 HClO 4
1c. 3 NO 2 + H 2 O 
→ 2 HNO3 + NO
1d. PCl3 + 3 H 2 O 
→ H 3 PO3 + 3 HCl
3a. 3 PbO + 2 NH 3 
→ 3 Pb + N 2 + 3 H 2 O
3b. 2 FeSO 4 
→ Fe 2 O3 + 2 SO 2 +
1
2
O 2 or 4 FeSO 4 
→ 2 Fe 2 O3 + 4 SO 2 + O 2
3c. 6 S2 Cl2 + 16 NH 3 
→ N 4 S4 + 12 NH 4 Cl +S8
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3d. 2 C3 H 7 CHOHCH(C2 H 5 )CH 2 OH + 23 O 2 
→16 CO 2 +18 H 2 O
5a. 2 Mg ( s ) + O 2 ( g ) → 2 MgO ( s )
5b. 2 NO ( g ) + O 2 ( g ) → 2 NO 2 ( g )
5c. 2 C2 H 6 ( g ) + 7 O 2 ( g ) → 4 CO 2 ( g ) + 6 H 2 O ( l )
5d. Ag 2 SO 4 ( aq ) + BaI 2 ( aq ) → BaSO 4 ( s ) + 2 AgI ( s )
7a. 2 C4 H10 (l) +13O 2 ( g ) → 8CO 2 ( g ) +10 H 2 O ( l )
7b. 2 CH 3 CH(OH)CH 3 (l) + 9 O 2 ( g ) → 6 CO 2 ( g ) + 8 H 2 O ( l )
7c. CH 3 CH(OH)COOH ( s ) + 3O 2 ( g ) → 3CO 2 ( g ) + 3H 2 O ( l )
∆
→ N2 O ( g ) + 2 H2 O ( g )
9a. NH 4 NO3 ( s ) 
9b. Na 2 CO3 ( aq ) + 2 HCl ( aq ) → 2 NaCl ( aq ) + H 2 O ( l ) + CO 2 ( g )
9c. 2 CH 4 ( g ) + 2 NH 3 ( g ) + 3O 2 ( g ) → 2 HCN ( g ) + 6 H 2 O ( g )
11. 2 N2H4(g) + N2O4(g) → 4 H2O(g) + 3 N2(g)
13. 2 Cr(s) + 3 O2(g) → 2 CrO3(s)
15. 785 g
17a. 0.402 mol O 2
17b. 128 g KClO3
17c. 43.9 g KCl
19. 96.0 g Ag 2 CO3
21a. 12.2 g H 2
21b. 48.1 g H 2 O
21c. 284 g CaH 2
23. 79.7% Fe 2 O3
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25. % by mass B10 H14 = 25.8%
27. 1.03g H 2
29. Al produces the largest amount of H 2 per gram of metal.
31a. 0.408 M
31b. 0.154 M
31c. 1.53M
33a. 1.753 M
33b. 0.320 M CO(NH 2 ) 2
33c. 0.206 M
35a. 4.73g
35b. 44.1mL CH 3OH
37a. 4.7
mmol C6 H12 O6
L
37b. Molarity
=
4.7 ×10−3
mol C6 H12 O6
L
39. Solution (d) is a 0.500 M KCl solution.
41. The 46% by mass sucrose solution is the more concentrated.
43. 0.0820 M
45. 0.236 M
47. The ratio of the volume of the volumetric flask to that of the pipet would be 20:1. We could
use a 100.0-mL flask and a 5.00-mL pipet, a 1000.0-mL flask and a 50.00-mL pipet, or a 500.0mL flask and a 25.00-mL pipet. There are many combinations that could be used.
49a. 0.177 g Na 2S
49b. 0.562 g Ag 2S
51. 59.4 mL K 2 CrO 4
53. 8.46 ×10−3
mol HNO3
L
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55a. 0.0693mol AlCl3
55b. 2.91 M AlCl3
57. 12.8 g Ag 2 CrO 4
59. 0.624g Na
61. 0.2649 M
63. 3.00 moles of NO (g)
65. HNO3 (aq) is the limiting reactant, it will be completely consumed, leaving some Cu
unreacted.
67. 143g Na 2 CS3
69a. 10.5g NH
3
69b. 10.1 g excess Ca ( OH )2
71. 211.51 g CrSO 4
73a. 1.80 mol CCl4
73b. 1.55 mol CCl2 F2
73c. 86.1% yield
75. 87.6%
81. A main criterion for choosing a synthesis reaction is how economically it can be run. In the
analysis of a compound, on the other hand, it is essential that all of the material present be
detected. Therefore, a 100% yield is required; none of the material present in the sample can be
lost during the analysis.
84. 1.22 ×103 g CO 2
86. 0.0386 g C2 H 6
87. 1.34 kg AgNO3 per kg of I2 produced.
89a.
∆
SiO2(s) + 2 C(s) 
→ Si(s) + 2 CO(g)
Si(s) + 2 Cl2(g) → SiCl4(l)
SiCl4(l) + 2 H2(g) → Si(s, ultrapure) + 4 HCl(g)
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89b. 885 g C , 5.05 × 103 g Cl2 , 144 g H 2 .
91. 73.33 %
Integrative and Advanced Exercises
∆
93a. CaCO 3 (s) 
→
CaO(s) + CO 2 (g)
∆
93b. 2 ZnS(s) + 3 O 2 (g) 
→
2 ZnO(s) + 2 SO 2 (g)
93c. C 3 H 8 (g) + 3 H 2 O(g) 
→ 3 CO(g) + 7 H 2 (g)
93d. 4 SO 2 (g) + 2 Na 2 S(aq) + Na 2 CO 3 (aq) 
→ CO 2 (g) + 3 Na 2 S 2 O 3 (aq)
95. 1.96 ×104 g LiOH
96. 68.0% CaCO3
98. 3 FeS + 5 O2 → Fe3O4 + 3 SO2
99. 8.88 M CH 3CH 2 OH
101. 143 mL
105. 0.2 cm 2
106. 0.365g Zn
114. 9.2% ( C2 H 5 )2 O , 90.8% CH 3CH 2 OH .
115. 16.95 %
116a. Cu 5 (CrO 4 ) 2 (OH)6
5 CuSO 4 (aq) + 2 K 2 CrO 4 (aq) + 6 H 2 O (l)
116b.
↓
Cu 5 (CrO 4 ) 2 (OH)6 (s) + 2 K 2SO 4 (aq) + 3 H 2SO 4 (aq)
117. C3 H 4 O 4 (l) + 2 O 2 (g) 
→ 3 CO 2 (g) + 2 H 2 O(l)
118. 5.2 g Fe , mass of excess Fe 2 O 3 = 2.1 g.
119. 0.850 g AgNO3
120. The balanced equation for the reaction is: S 8 (s) + 4 Cl 2 (g) → 4 S 2 Cl 2 (l). Both “a” and
“b” are consistent with the stoichiometry of this equation.
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121. 1.25 g C3 N 3 (OH)3
123. We must use all of the most concentrated solution and dilute this solution down using the
next most concentrated solution. A total of 374 mL may be prepared this way.
127a. 2 C 3 H 6 (g) + 2 NH 3 (g) + 3 O 2 (g) → 2 C 3 H 3 N(l) + 6 H 2 O(l)
127b. 555 kg NH 3
Self-Assessment Exercises
135. The answer is (d).
136. The answer is (d).
137. The answer is (a).
138. The answer is (a).
139. The answer is (c).
140. The answer is (d).
141. The answer is (b).
142. The answer is (d).
143a. 2 C 8 H 18 + 25 O 2 → 16 CO 2 + 18 H 2 O
143b. 2 C8H18 + 25 O2 → 12 CO2 + 4 CO + 18 H2O
144. Dolomite is the compound.
145. The answer is (b).
146. The answer is (c).
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