Post on 08-Mar-2018
General, Organic, and Biological Chemistry, 3e (Timberlake) Chapter 9
1
Equilibrium
This set includes all problems but you can focus only on the following numbers; 14,15,16,23,27,29,31,34,39,42,43, 46-50. The exam will come from those problems.9.1
2
Multiple Choice Questions1)
3
A catalyst is A)
4
a reactant in a chemical reaction. B)
5
a product in a chemical reaction. C)
6
a substance that speeds up a reaction without being consumed in the reaction. D)
7
a substance that increases the energy of the products. E)
8
a substance that decreases the energy of the products.
9
2)
10
When a reaction is at equilibrium, A)
11
all reaction stops. B)
12
no more reactants are converted to products. C)
13
the reaction is no longer reversible. D)
14
the forward and reverse reactions occur at the same rate. E)
15
the products and reactants have the same energy content
16
3)
17
For the following equilibrium reaction, which cause and effect are correctly matched?
CO(g) + 2H2 (g) ⇌ CH3OH(g) + heat
A)
18
add heat, shift right B)
19
add CO, shift left C)
20
remove CH3OH, shift left D)
21
remove heat, no change E)
22
remove H2, shift left
23
4)
24
The activation energy of a chemical reaction is the energy that A)
25
must be removed from the mixture. B)
26
must be released from the mixture. C)
27
initiates the reaction. D)
28
activates the catalyst. E)
29
is the difference in the energies of the starting materials and products.
30
5)
31
A chemical reaction has reached equilibrium when A)
32
the concentrations of reactants and products are equal. B)
33
all reactants have been converted to products. C)
34
all products have been removed from the reaction mixture. D)
35
the catalyst has been used up. E)
36
the rate of the forward reaction equals the rate of the reverse reaction.
37
38
6)
39
In a catalyzed chemical reaction, one function of a catalyst is to A)
40
increase the number of successful reactant collisions. B)
41
decrease the concentration of reactants. C)
42
change the equilibrium concentrations of the products and reactants. D)
43
increase the energy given off during the reaction. E)
44
increase the temperature at which the reaction is carried out.
45
7)
46
In the following gas phase reaction, what is the effect of adding more NO2 to the starting reaction mixture?
2NO2 ⇌ N2O4
A)
47
It would make the reaction more endothermic. B)
48
It would make the reaction more exothermic. C)
49
It would slow the reaction down. D)
50
It would decrease the final quantity of products. E)
51
It would increase the final quantity of products.
52
8)
53
The physiological equilibrium system that keeps the temperature of the body constant is called __________.
A)
54
stimulation B)
55
regulation C)
56
metabolism D)
57
homeostasis E)
58
catalysis
59
9)
60
When you open a bottle of a soft drink and leave it open, the drink eventually goes flat. This happens because the equilibrium between carbonic acid and carbon dioxide shifts to produce
A)
61
more carbonic acid. B)
62
more water. C)
63
more oxygen. D)
64
more carbon dioxide. E)
65
more hydrogen ions.
66
10)
67
Iron metal reacts with oxygen gas to produce iron(III) oxide. What will be the effect of increasing the pressure of oxygen gas in a closed reaction vessel?
A)
68
Less reaction will take place. B)
69
More iron oxide will be produced. C)
70
The reaction mixture will catch fire. D)
71
There is no effect; a catalyst is needed. E)
72
The rate of production of iron oxide will slow down.
73
74
11)
75
In the following gas phase reaction, what is the effect on the direction of the reaction if more SO3 is added to the reaction mixture?
2SO2 + O2 ⇌ 2SO3
A)
76
The equilibrium shifts to produce more products. B)
77
The position of the equilibrium remains unchanged. C)
78
The rate of formation of products is increased. D)
79
The equilibrium shifts to produce more reactants. E)
80
The catalyst for the reaction is used up.
81
12)
82
In the following gas phase reaction, Kc is much less than 1. At equilibrium, which of the following statements is true?
COCl2 ⇌ CO + Cl2
A)
83
The concentration of reactant is much greater than the concentration of products. B)
84
The concentration of products is much greater than the concentration of reactants. C)
85
The concentrations of products and reactants are approximately equal. D)
86
A catalyst will increase the concentration of products formed. E)
87
At equilibrium, the concentrations of reactants and products are equal.
88
13)
89
In the reaction of nitrogen gas with oxygen gas to produce nitrogen oxide, what is the effect of adding more oxygen gas to the initial reaction mixture? The reaction is shown below.
N2(g) + O2(g) ⇌ 2NO(g)
A)
90
The equilibrium shifts to produce more N2. B)
91
The equilibrium shifts to produce more NO. C)
92
The equilibrium is not affected. D)
93
Extra catalyst is required to reach equilibrium. E)
94
The temperature of the reaction mixture is raised.
95
14)
96
The equilibrium constant for the production of carbon dioxide from carbon monoxide and oxygen is Kc = 2 x 1011. This means that the reaction mixture at equilibrium is likely to consist of
A)
97
mostly starting materials. B)
98
an equal mixture of products and reactants. C)
99
twice as much starting material as product. D)
100
twice as much product as starting material. E)
101
mostly products.
102
103
15)
104
Which of the following equilibrium constants indicates the reaction that gives the smallest amount of product?
A)
105
Kc = 5 × 10-10
B)
106
Kc = 5 × 10-1
C)
107
Kc = 5 × 100 D)
108
Kc = 5 × 101 E)
109
Kc = 5 × 1010
110
16)
111
The reaction of hemoglobin with oxygen can be written as follows.
Hb + O2 ⇌ HbO2
If the amount of oxygen available to the blood decreases significantly, what happens to the individual involved?
A)
112
Hypoxia results. B)
113
Anemia results. C)
114
Nitrogen narcosis results. D)
115
Oxygen poisoning results. E)
116
Acclimatization results.
117
17)
118
What is the correct form for the equilibrium constant expression for this reaction?
H2 (g) + F2 (g) ⇌ 2 HF(g)
A)
119
B)
120
C)
121
D)
122
E)
123
124
18)
125
The rate of any chemical reaction can be determined by observing A)
126
the amount of product formed in a unit of time. B)
127
the ratio of product concentration to reactant concentration. C)
128
the percent composition of the final product. D)
129
the theoretical yield of the reaction. E)
130
the number of chemical bonds broken and remade.
131
132
19)
133
In any chemical reaction, the rate of the reaction can be increased by A)
134
decreasing the temperature. B)
135
changing the size of the container. C)
136
adding water to the reaction. D)
137
adding product molecules to the reaction mixture. E)
138
increasing the concentrations of the reactants.
139
20)
140
Refrigerating perishable foods affects biochemical reactions by A)
141
increasing concentrations of antioxidants. B)
142
removing bacteria. C)
143
decreasing the rate of reactions affecting spoilage. D)
144
catalyzing the removal of harmful chemicals from the foods. E)
145
improving the appearance of the foods.
146
21)
147
In a catalytic converter in an automobile, the reaction of carbon monoxide with oxygen produces __________.
A)
148
carbon dioxide B)
149
carbon and more oxygen C)
150
water D)
151
methane E)
152
nitrogen oxide
153
22)
154
One metal that is used as a catalyst in a catalytic converter in an automobile is __________. A)
155
carbon B)
156
iron C)
157
copper D)
158
platinum E)
159
plutonium
160
23)
161
A reaction that can proceed in either the forward or the reverse direction as written is called a __________ reaction.
A)
162
reversible B)
163
miniscule C)
164
microscopic D)
165
solid phase E)
166
favored
167
24)
168
For the equilibrium reaction of carbon dioxide with water, what is the appropriate equation?
A)
169
H2O + CO ⇌ H2CO3 B)
170
H2O + 2CO2 ⇌ H2CO3 C)
171
H2O + CO2 ⇌ H2CO3 D)
172
H2O + CO2 ⇌ HCO3 E)
173
H2O + CO2 ⇌ H2CO2
174
175
25)
176
What is the correct form of the equilibrium constant for the reaction of hydrogen and oxygen to form water? The equation is:
2H2(g) + O2(g) ⇌ H2O(g)
A)
177
Kc = B)
178
Kc = C)
179
Kc = D)
180
Kc = E)
181
Kc =
182
26)
183
The equilibrium constant for the formation of ammonia from nitrogen and hydrogen is 1.6 × 102. What is the form of the equilibrium constant?
A)
184
B)
185
C)
186
D)
187
E)
188
189
190
27)
191
The reaction for the decomposition of PCl5 to chlorine and PCl3 is shown below.
PCl5(g) ⇌ PCl3(g) + Cl2(g)
If the equilibrium concentrations are [PCl5] = 1.0 M, [PCl3] = 0.10 M, [Cl2] = 0.10 M, what is the value of the equilibrium constant?
A)
192
1.0 × 10-2 B)
193
1.0 × 10-4 C)
194
10 × 10-2 D)
195
1.0 × 102 E)
196
2.0 × 10-2
197
28)
198
The equilibrium for the reaction for the decomposition of PCl5 to chlorine and PCl3 is 0.042.
PCl5(g) ⇌ PCl3(g)+ Cl2(g)
If the equilibrium concentrations are [PCl3] = 0.010 M, [Cl2] = 0.10 M, what is the value of [PCl5]?
A)
199
0.010 M B)
200
0.0020 M C)
201
0.042 M D)
202
0.024 M E)
203
0.0010 M
204
29)
205
PCl5 (g) ⇌ PCl3 (g)+ Cl2 (g)
For the reaction at equilibrium, if the volume of the container is increased, the amount of PCl5 present will
A)
206
decrease. B)
207
increase. C)
208
double. D)
209
stay the same. E)
210
triple.
211
30)
212
The value of the equilibrium constant for the combination of nitrogen and oxygen to make NO is 2 × 10-9. What does this tell you about the concentrations of materials in the equilibrium mixture?
A)
213
The concentration of products exceeds the concentration of reactants. B)
214
The concentrations of reactants and products are equal. C)
215
The reactants are solids. D)
216
The concentration of reactants exceeds the concentration of products. E)
217
The products are solids.
218
219
31)
220
Carbon monoxide binds to hemoglobin 140 times more strongly than oxygen does. What does this tell you about the equilibrium constants for the two reactions of hemoglobin with carbon monoxide and oxygen?
A)
221
The equilibrium constant for the binding of CO is greater. B)
222
The equilibrium constant for the binding of oxygen is greater. C)
223
The concentration of carbon monoxide at equilibrium is twice that of oxygen. D)
224
Oxygen and carbon monoxide have the same formula mass. E)
225
Oxygen and carbon monoxide react with hemoglobin in different fashions.
226
32)
227
Treatment of carbon monoxide poisoning can be accomplished by the use of pure oxygen for breathing. This is an example of the use of __________ in a clinical setting.
A)
228
the ideal gas law B)
229
Le Chatelier's principle C)
230
Henry's law D)
231
conservation of mass E)
232
a precipitation reaction
233
33)
234
In the reaction of nitrogen and hydrogen to give ammonia, all the reactants and products are __________.
A)
235
gases B)
236
liquids C)
237
solids D)
238
boiling E)
239
frozen
240
34)
241
In the reaction of carbon dioxide with water to give carbonic acid, the only gaseous component is the carbon dioxide. What will happen to the equilibrium concentration of carbonic acid if the pressure of carbon dioxide is increased in the container?
A)
242
The concentration of carbonic acid will increase. B)
243
The carbonic acid concentration will decrease. C)
244
The carbonic acid concentration will stay the same. D)
245
There will be twice as much carbonic acid as carbon dioxide. E)
246
There will be more water available for the reaction.
247
35)
248
In an exothermic reaction, heat can be considered a __________. A)
249
reactant B)
250
product C)
251
rate D)
252
catalyst E)
253
determinant
254
255
36)
256
An equilibrium in which all the components are gases is a __________ equilibrium. A)
257
heterogeneous B)
258
liquid C)
259
catalytic D)
260
homogeneous E)
261
reversible
262
37)
263
For the reaction of carbon with carbon dioxide to make carbon monoxide, the reaction is as follows.
C(s) + CO2(g) ⇌ 2CO(g)
This is an example of a __________ equilibrium. A)
264
heterogeneous B)
265
homogeneous C)
266
gas D)
267
catalytic E)
268
irreversible
269
38)
270
For the reaction of carbon with carbon dioxide to make carbon monoxide, the reaction is as follows. Write the form of the Kc.
C(s) + CO2(g) ⇌ 2CO(g)
A)
271
Kc = B)
272
Kc = C)
273
Kc = D)
274
Kc = E)
275
Kc =
276
277
39)
278
For the reaction of carbon with carbon dioxide to make carbon monoxide, one set of conditions produced a Kc = 1.2 × 10-1. At equilibrium at a certain temperature, the concentration of product was 0.60 M. What was the concentration of carbon dioxide at that temperature?
C(s) + CO2(g) ⇌ 2CO(g)
A)
279
3.0 M B)
280
0.60 M C)
281
0.36 M D)
282
3.33 M E)
283
5.0 M
284
40)
285
For the reaction of carbon with carbon dioxide to make carbon monoxide, the reaction is as follows.
C(s) + CO2(g) ⇌ 2CO(g)
Adding additional C(s) to the reaction container will cause __________ to occur. A)
286
the formation of more CO B)
287
the formation of more CO2 C)
288
a decrease in the amount of CO D)
289
B and C E)
290
no change in the amounts of CO and CO2
291
41)
292
For the following reaction, the equilibrium constant Kc is 2.0 at a certain temperature. If the concentration of both products is 0.10 M at equilibrium, what is the concentration of the starting material, NOBr?
2NOBr(g) ⇌ 2NO(g) + Br2(g)
A)
293
5 × 10-4 M B)
294
2.2 × 10-4 M C)
295
5 × 10-2 M D)
296
2.2 × 10-2 M E)
297
2.2 M
298
299
42)
300
For the following reaction, the equilibrium constant Kc is 2.0 at a certain temperature. The reaction is endothermic. What do you expect to happen to the concentration of NO if the temperature is doubled?
2NOBr(g) ⇌ 2NO(g) + Br2(g)
A)
301
The concentration of NO will increase. B)
302
The concentration of NO will decrease. C)
303
There will be no change in [NO]. D)
304
A catalyst will be needed to make a change in concentration. E)
305
The change in concentration of [NO] will depend on the size of the vessel.
306
43)
307
For the following reaction, the equilibrium constant Kc is 2.0 at a certain temperature. Bromine can be liquefied easily and removed from the reaction vessel as it is formed. If this is done, how will it affect the equilibrium reaction?
2NOBr(g) ⇌ 2NO(g) + Br2(g)
A)
308
More products will be made as Br2 is removed. B)
309
There will be a larger proportion NOBr in the vessel when equilibrium is reached. C)
310
Less NO will be made. D)
311
The pressure in the vessel will increase. E)
312
The equilibrium constant will change.
313
44)
314
What is the solubility constant expression, Ksp, for copper(II) hydroxide, Cu(OH)2? A)
315
Ksp = B)
316
Ksp = C)
317
Ksp =[Cu2+][ OH-]2 D)
318
Ksp =[Cu2+]2[OH-] E)
319
Ksp =[Cu2+][OH-]
320
45)
321
Which of the following is the balanced equilibrium equation for the solubility of PbCl2 (s)? A)
322
2 Cl- (aq) + Pb2+ (aq) ⇌ PbCl2 (s) B)
323
PbCl2 (s) ⇌ 2 Pb2+ (aq) + Cl-(aq) C)
324
PbCl2 (s) ⇌ Pb2+ (aq) + Cl-(aq) D)
325
PbCl2 (s) ⇌ Pb2+ (aq) + 2Cl-(aq)
326
327
46)
328
If a slightly soluble salt has a solubility product expression of Ksp =[Al3+][OH- ]3 , which of the following is the balanced equilibrium equation for this salt?
A)
329
Al3+ (aq)+ 3 OH- (aq) ⇌ Al(OH)3 (s) B)
330
Al(OH)3 (s) ⇌ Al3+ (aq) + 3 OH- (aq) C)
331
Al3OH(s) ⇌ 3 Al3+ (aq) + OH- (aq) D)
332
Al(OH)3 (s) ⇌ 3 Al3+ (aq) + OH- (aq)
333
47)
334
A saturated solution of Cu(OH)2 at 85 °C has [Cu2+] = 0.013 M and [OH-] = 0.026 M. What is the value of the Ksp for Cu(OH)2 at 85 °C?
A)
335
3.4 x 10-4 B)
336
8.8 x 10-6 C)
337
4.4 x 10-6 D)
338
6.8 x 10-4
339
48)
340
What are [Cu+] and [Br-] in a saturated CuBr solution if the Ksp of CuBr is 2.3 x 10-12? A)
341
1.5 x 10-6 M B)
342
4.6 x 10-12 M C)
343
1.2 x 10-12 M D)
344
5.3 x 10-24 M
345
49)
346
Calculate the molar solubility (S) of SrSO4 if the Ksp is 3.44 x 10-7. A)
347
3.44 x 10-7 M B)
348
5.87 x 10-4 M C)
349
1.18 x 10-13 M D)
350
1.72 x 10-7 M
351
50)
352
If the Ksp of SrSO4 is 3.44 x 10-7 and the Ksp of CuBr is 2.3 x 10-12, which compound has the higher molar solubility (S)?
A)
353
SrSO4 B)
354
CuBr C)
355
Both compounds have the same molar solubility. D)
356
Not enough information is given to answer this question
357
9.2
358
Bimodal Questions1)
359
Any reaction that absorbs 150 kcal of energy can be classified as __________. A)
360
endothermic B)
361
exothermic C)
362
activated D)
363
reduction E)
364
oxidation
365
2)
366
The __________ is the energy difference between reactants and products in a chemical reaction.
A)
367
transition energy B)
368
activation energy C)
369
product energy D)
370
overall energy E)
371
heat of reaction
372
3)
373
What is the correct form of the equilibrium constant for this reaction?
2 H2O2 (g) ⇌ 2 H2O (g) + O2 (g)
A)
374
B)
375
C)
376
D)
377
378
4)
379
For the following reaction, the equilibrium constant Kc is 2.0 at a certain temperature. Write the form of the equilibrium constant, Kc.
2NOBr(g) ⇌ 2NO(g) + Br2(g)
A)
380
B)
381
C)
382
D)
383
E)
384
385
386
9.3
387
Short Answer Questions1)
388
The rule or principle that describes the effect of changing reaction conditions on an equilibrium is known as __________ principle.
389
2)
390
A mixture at equilibrium that contains less product than reactant has a Kc that is __________ than 1.
391
3)
392
Write the equilibrium constant expression for the reaction of nitrogen and hydrogen to give ammonia, NH3.
393
4)
394
The equilibrium between hemoglobin and oxyhemoglobin in the blood can be represented by the following reaction. Write the form of the equilibrium constant expression.
Hb + O2 ⇌ HbO2
395
5)
396
An equilibrium constant with a value greater than 1 means the reaction favors the __________.
397
9.4
398
True/False Questions1)
399
An equilibrium constant greater than 1 for a reaction indicates that the reaction favors formation of the products.
400
2)
401
An equilibrium constant Kc = 1 × 107 for a reaction indicates that the reaction favors product formation.
402
3)
403
An equilibrium constant Kc = 1 × 10-3 for a reaction indicates that the reaction favors product formation.
404
4)
405
If the equilibrium constant for a reaction is 1 × 10-5, this means that the reaction does not proceed well to products.
406
5)
407
The equilibrium constant for a reaction does not change with temperature.
408
6)
409
Activation energy is always a large amount of energy.
410
411
7)
412
At equilibrium, the concentrations of the reactants and products are always equal.
413
8)
414
The rate of a chemical reaction depends on temperature.
415
9)
416
The rate of a chemical reaction is not affected by the concentration of reactants.
417
10)
418
A catalyst for a chemical reaction affects the magnitude of the equilibrium constant.
419
11)
420
One of the substances acted upon by a catalytic converter in an automobile is carbon dioxide.
421
12)
422
A heterogeneous equilibrium is one in which the reactants and products are found in two or more physical states.
423
13)
424
An example of a stress on an equilibrium is the increase of pressure in a closed system when the pressure of a reactant gas is increased from 1.0 atm to 2.0 atm.
425
14)
426
A catalyst lowers the activation energy of a chemical reaction.
427
9.5
428
Matching QuestionsIndicate the effect of each change upon the rate of a reaction.
1)
429
adding a catalyst
430
A)
431
decreases
2)
432
removing some reactant
433
B)
434
increases
3)
435
The temperature is doubled.
4)
436
The concentration of a reactant is decreased.
5)
437
More collisions between molecules occur.
438
439
440
441
442
443
444
445
446
447