Unit 14 Practice Multiple Choice

Name: ________________________ Class: ___________________ Date: __________
Chapter 14 Practice test
Multiple Choice
Identify the choice that best completes the statement or answers the question.
____
1) A burning splint will burn more vigorously in pure oxygen than in air because ________.
A) oxygen is a reactant in combustion and concentration of oxygen is higher in pure oxygen
than is in air
B) oxygen is a catalyst for combustion
C) oxygen is a product of combustion
D) nitrogen is a product of combustion and the system reaches equilibrium at a lower
temperature
E) nitrogen is a reactant in combustion and its low concentration in pure oxygen catalyzes
the combustion
The data in the table below were obtained for the reaction:
A+BP
Experiment
Number
1
2
3
____
[A](M)
[B](M)
0.273
0.273
0.819
0.763
1.526
0.763
Initial Rate
(M/s)
2.83
2.83
25.47
2) The rate law for this reaction is rate = ________.
A) k[A][B]
B) k[P]
C) k[A]2[B]
D) k[A]2[B]2
E) k[A]2
The data in the table below were obtained for the reaction:
2 ClO2 (aq) + 2 OH– (aq)  ClO3– (aq) + ClO2– (aq) + H2O (1)
____
3) What is the overall order of the reaction?
A) 4
B) 0
C) 1
D) 2
E) 3
1
ID: A
Name: ________________________
____
ID: A
4) The reaction
CH3–N=C  CH3–C=N
is a first-order reaction. At 230.3 °C, k = 6.29  10–4s–1. If
is 1.00  10–3 initially,
________ after 1.000  103 s.
A) 5.33  10–4
B) 2.34  10–4
C) 1.88  10–3
D) 4.27  10–3
E) 1.00  10–6
____
5) The following reaction is second order in [A] and the rate constant is 0.025 M –1s–1:
A  B
The concentration of A was 0.65 M at 33 s. The initial concentration of A was ________ M.
A) 2.4
B) 0.27
C) 0.24
D) 1.4
E) 1.2  10–2
____
6) At elevated temperatures, methylisonitrile (CH3NC) isomerizes to acetonitrile (CH3CN):
CH3NC (g)  CH3CN (g)
The reaction is first order in methylisonitrile. The attached graph shows data for the reaction obtained at
198.9 °C.
The rate constant for the reaction is ________ s –1.
A) –1.9  104
B) +1.9  104
C) –5.2  10–5
D) +5.2  10–5
E) +6.2
2
is
Name: ________________________
____
ID: A
7) Which energy difference in the energy profile below corresponds to the activation energy for the forward
reaction?
A)
B)
C)
D)
E)
x
y
x+y
x–y
y–x
____
8) In general, as activation energy increases, reaction rate ________.
A) goes down if the reaction is exothermic
B) goes down if the reaction is endothermic
C) stays the same regardless of whether the reaction is exothermic or endothermic
D) goes down regardless of whether the reaction is exothermic or endothermic
E) none of the above
____
9) A possible mechanism for the overall reaction
Br2 (g) + 2NO (g)  2NOBr (g)
is
NO (g) + Br2 (g)
NOBr2 (g) + NO (g)
NOBr2 (g)
2NOBr
(fast)
(slow)
The rate law for formation of NOBr based on this mechanism is rate = ________.
A) k1[NO]1/2
B) k1[Br2]1/2
C) (k2k1/k–1)[NO]2[Br2]
D) (k1/k–1)2[NO]2
E) (k2k1/k–1)[NO][Br2]2
____ 10) A catalyst can increase the rate of a reaction ________.
A) by changing the value of the frequency factor (A)
B) by increasing the overall activation energy (E a) of the reaction
C) by lowering the activation energy of the reverse reaction
D) by providing an alternative pathway with a lower activation energy
E) All of these are ways that a catalyst might act to increase the rate of reaction.
3
Name: ________________________
ID: A
____ 11) The active site of nitrogenase is a cofactor that contains two transition metals. These transition metals are
________.
A) Cr and Mg
B) Mn and V
C) Os and Ir
D) Fe and Zn
E) Fe and Mo
____ 12) Consider the following reaction:
A  2C
The average rate of appearance of C is given by [C]/t. Comparing the rate of appearance of C and the rate
of disappearance of A, we get [C]/t = ________  (–[A]/t).
A) +2
B) –1
C) +1
D) +1/2
E) –1/2
A flask is charged with 0.124 mol of A and allowed to react to form B according to the reaction A(g)  B(g).
The following data are obtained for [A] as the reaction proceeds:
____ 13) The average rate of disappearance of A between 20 s and 30 s is ________ mol/s.
A) 5.0  10–4
B) 1.6  10–2
C) 1.5  10–3
D) 670
E) 0.15
4
Name: ________________________
ID: A
The peroxydisulfate ion (S 2O82–) reacts with the iodide ion in aqueous solution via the reaction:
S2O82– (aq) + 3I–  2SO4 (aq) + I3– (aq)
An aqueous solution containing 0.050 M of S 2O82– ion and 0.072 M of I – is prepared, and the progress of the
reaction followed by measuring [I–]. The data obtained is given in the table below.
____ 14) The average rate of disappearance of I– in the initial 400.0 s is ________ M/s.
A) 6.00
B) 3.8  10–5
C) 1.4  10–4
D) 2.7  104
E) 3.2  10–4
____ 15) The concentration of S2O82– remaining at 1600 s is ________ M.
A) 0.036
B) 0.014
C) 0.043
D) 0.064
E) 0.029
____ 16) At elevated temperatures, methylisonitrile (CH3NC) isomerizes to acetonitrile (CH3CN):
CH3NC (g)  CH3CN (g)
At the start of the experiment, there are 0.200 mol of reactant (CH 3NC) and 0 mol of product (CH3CN) in the
reaction vessel. After 25 min of reaction, 0.108 mol of reactant (CH 3NC) remain. The average rate of
decomposition of methyl isonitrile, CH3NC, in this 25 min period is ________ mol/min.
A) 3.7  10–3
B) 0.092
C) 2.3
D) 4.3  10–3
E) 0.54
____ 17) The overall order of a reaction is 1. The units of the rate constant for the reaction are ________.
A) M/s
B) M–1s–1
C) 1/s
D) 1/M
E) s/M2
5
Name: ________________________
ID: A
____ 18) A reaction was found to be third order in A. Increasing the concentration of A by a factor of 3 will cause the
reaction rate to ________.
A) remain constant
B) increase by a factor of 27
C) increase by a factor of 9
D) triple
E) decrease by a factor of the cube root of 3
The data in the table below were obtained for the reaction:
A + B  P
____ 19) The overall order of the reaction is ________.
A) 1
B) 2
C) 3
D) 4
E) 0
____ 20) The half-life of a first-order reaction is 13 min. If the initial concentration of reactant is 0.13 M, it takes
________ min for it to decrease to 0.085 M.
A) 12
B) 10.
C) 8.0
D) 11
E) 7.0
____ 21) The reaction below is first order in [H2O2]:
2H2O2 (l)  2H2O (l) + O2 (g)
A solution originally at 0.600 M H 2O2 is found to be 0.075 M after 54 min. The half-life for this reaction is
________ min.
A) 6.8
B) 18
C) 14
D) 28
E) 54
6
Name: ________________________
ID: A
____ 22) A second-order reaction has a half-life of 12 s when the initial concentration of reactant is 0.98 M. The rate
constant for this reaction is ________ M –1s–1.
A) 12
B) 2.0  10–2
C) 8.5  10–2
D) 4.3  10–2
E) 4.3
____ 23) The reaction shown below is ________, and it is a ________ elementary reaction.
A + B + C  ABC
A) termolecular, rare
B) termolecular, common
C) unimolecular, common
D) bimolecular, rare
E) unimolecular, rare
____ 24) At elevated temperatures, dinitrogen pentoxide decomposes to nitrogen dioxide and oxygen:
2N2O5(g)  4NO2 (g) + O2 (g)
When the rate of formation of O2 is 2.2  10–4 M/s, the rate of decomposition of N2O5 is ________ M/s.
A) 7.2  10–3
B) 3.6  10–3
C) 1.8  10–3
D) 1.4  10–2
E) 0.00090
____ 25) The combustion of ethylene proceeds by the reaction
C2H4 (g) + 3O2 (g)  2CO2 (g) + 2H2O (g)
When the rate of disappearance of O2 is 0.13 M s–1, the rate of disappearance of C2H4 is ________ M s–1.
A) 0.087
B) 0.043
C) 0.39
D) 0.20
E) 0.26
____ 26) In a linear graphical representation of a zero-order reaction, what value is represented by the y-intercept of the
line drawn from plotting [A] vs. time?
A) [A]0
B) ln[A]0
C) 1/[A]0
D) [A]02
E) [A]/k
7
Name: ________________________
ID: A
____ 27) The rate constant of a first-order process that has a half-life of 462 s is ________ s –1.
A) 1.50  10–3
B) 3.20  102
C) 6.67  102
D) –1.08  10–3
E) 2.16  10–3
____ 28) The elementary reaction
2NO2 (g)  2NO (g) + O2 (g)
is second order in NO2 and the rate constant at 660 K is 5.23 M –1s–1. The reaction half-life at this temperature
when [NO2]0 = 0.45 M is ________ s.
A) 2.4
B) 7.6
C) 0.19
D) 0.13
E) 0.42
____ 29) The rate constant for a particular second-order reaction is 0.47 M –1s–1. If the initial concentration of reactant is
0.25 mol/L, it takes ________ s for the concentration to decrease to 0.20 mol/L.
A) 2.1
B) 1.4
C) 1.0
D) 0.47
E) 0.20
____ 30) The rate constant for a second-order reaction is 0.13 M –1s–1. If the initial concentration of reactant is 0.26 mol/L,
it takes ________ s for the concentration to decrease to 0.07 mol/L.
A) 0.017
B) 1.4
C) 14
D) 80.
E) 10.
____ 31) A particular first-order reaction has a rate constant of 1.35  102 s–1 at 25.0 °C. What is the magnitude of k at
65.0 °C if Ea = 55.5 kJ/mol?
A) 1.92  103
B) 1.95  104
C) 358
D) 3.48  1073
E) 1.35  102
Short Answer
1) The relationship of absorbed light to the concentration of the substance absorbing the light is governed by
________.
8
Name: ________________________
ID: A
2) For the reaction aA + Bb  cC + dD, the rate law is ________.
3) If a rate law is second order (reactant), doubling the reactant ________ the reaction rate.
4) The Earth's ozone layer is located in the ________.
5) Reaction rates are affected by reactant concentrations and temperature. This is accounted for by the ________.
6) The minimum energy to initiate a chemical reaction is the ________.
7) Reaction rate data showing temperature dependence obey an equation devised by ________.
8) The number of molecules that participate as reactants defines the ________ of the reaction.
9) Elementary reactions involving the simultaneous collision of three molecules are ________.
10) A catalyst that is present in the same phase as the reacting molecules is called a(n) ________ catalyst.
11) A catalyst that is present in a different phase from the reacting molecules is called a(n) ________ catalyst.
12) The binding of molecules to the surface of a catalyst is referred to as ________.
13) The uptake of molecules into the interior of another substance is referred to as ________.
True/False
Indicate whether the statement is true or false.
____
1) Rates of reaction can be positive or negative.
____
2) The instantaneous rate of a reaction can be read directly from the graph of molarity versus time at any point on
the graph.
____
3) The overall reaction order is the sum of the orders of each reactant in the rate law.
____
4) Units of the rate constant of a reaction are independent of the overall reaction order.
____
5) The concentration of reactants or products at any time during the reaction can be calculated from the integrated
rate law.
____
6) The rate of a second order reaction can depend on the concentrations of more than one reactant.
____
7) The half-life for a first order rate law depends on the starting concentration.
____
8) The rate limiting step in a reaction is the slowest step in the reaction sequence.
____
9) Heterogeneous catalysts have different phases from reactants.
9
ID: A
Chapter 14 Practice test
Answer Section
MULTIPLE CHOICE
1) ANS:
OBJ:
2) ANS:
OBJ:
3) ANS:
OBJ:
4) ANS:
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5) ANS:
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6) ANS:
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7) ANS:
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8) ANS:
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9) ANS:
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10) ANS:
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11) ANS:
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12) ANS:
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13) ANS:
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14) ANS:
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15) ANS:
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16) ANS:
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17) ANS:
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18) ANS:
OBJ:
19) ANS:
OBJ:
20) ANS:
OBJ:
21) ANS:
OBJ:
A
14.1; G2
E
14.3; G4
E
14.3; G4
A
14.4; G4
D
14.4; G3
D
14.4; G3
A
14.5; G3
D
14.5; G2
C
14.6; G2
D
14.7; G2
E
14.7; G2
A
14.2; G2
C
14.2; G4
B
14.2; G3
A
14.2; G3
A
14.2; G4
C
14.3; G2
B
14.3; G4
B
14.3; G3
C
14.4; G4
B
14.4; G4
PTS: 1
DIF: 1
REF: Page Ref: 14.1
PTS: 1
DIF: 3
REF: Page Ref: 14.3
PTS: 1
DIF: 1
REF: Page Ref: 14.3
PTS: 1
DIF: 2
REF: Page Ref: 14.4
PTS: 1
DIF: 2
REF: Page Ref: 14.4
PTS: 1
DIF: 2
REF: Page Ref: 14.4
PTS: 1
DIF: 1
REF: Page Ref: 14.5
PTS: 1
DIF: 1
REF: Page Ref: 14.5
PTS: 1
DIF: 3
REF: Page Ref: 14.6
PTS: 1
DIF: 1
REF: Page Ref: 14.7
PTS: 1
DIF: 1
REF: Page Ref: 14.7
PTS: 1
DIF: 2
REF: Page Ref: 14.2
PTS: 1
DIF: 2
REF: Page Ref: 14.2
PTS: 1
DIF: 2
REF: Page Ref: 14.2
PTS: 1
DIF: 2
REF: Page Ref: 14.2
PTS: 1
DIF: 2
REF: Page Ref: 14.2
PTS: 1
DIF: 1
REF: Page Ref: 14.3
PTS: 1
DIF: 1
REF: Page Ref: 14.3
PTS: 1
DIF: 1
REF: Page Ref: 14.3
PTS: 1
DIF: 1
REF: Page Ref: 14.4
PTS: 1
DIF: 4
REF: Page Ref: 14.4
1
ID: A
22) ANS:
OBJ:
23) ANS:
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24) ANS:
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25) ANS:
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27) ANS:
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28) ANS:
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29) ANS:
OBJ:
30) ANS:
OBJ:
31) ANS:
OBJ:
C
14.4; G4
A
14.1; G4
A
14.2; G4
B
14.2; G4
A
14.4; G2
A
14.4; G4
E
14.4; G4
A
14.4; G4
D
14.4; G4
A
14.5; G4
PTS: 1
DIF: 2
REF: Page Ref: 14.4
PTS: 1
DIF: 4
REF: Page Ref: 14.1
PTS: 1
DIF: 1
REF: Page Ref: 14.2
PTS: 1
DIF: 2
REF: Page Ref: 14.2
PTS: 1
DIF: 4
REF: Page Ref: 14.4
PTS: 1
DIF: 2
REF: Page Ref: 14.4
PTS: 1
DIF: 2
REF: Page Ref: 14.4
PTS: 1
DIF: 2
REF: Page Ref: 14.4
PTS: 1
DIF: 1
REF: Page Ref: 14.4
PTS: 1
DIF: 4
REF: Page Ref: 14.5
PTS: 1
OBJ: 14.2; G2
2) ANS:
k[A]m[B]n
DIF: 1
REF: Page Ref: 14.2
PTS: 1
OBJ: 14.3; G2
3) ANS:
quadruples
DIF: 1
REF: Page Ref: 14.3
PTS: 1
OBJ: 14.3; G2
4) ANS:
stratosphere
DIF: 1
REF: Page Ref: 14.3
PTS: 1
OBJ: 14.4; G2
5) ANS:
collision model
DIF: 1
REF: Page Ref: 14.4
PTS: 1
OBJ: 14.5; G2
DIF: 1
REF: Page Ref: 14.5
SHORT ANSWER
1) ANS:
Beer's Law
2
ID: A
6) ANS:
activation energy
PTS: 1
OBJ: 14.5; G2
7) ANS:
Arrhenius
DIF: 1
REF: Page Ref: 14.5
PTS: 1
OBJ: 14.5; G2
8) ANS:
molecularity
DIF: 1
REF: Page Ref: 14.5
PTS: 1
OBJ: 14.6; G2
9) ANS:
termolecular
DIF: 1
REF: Page Ref: 14.6
PTS: 1
OBJ: 14.6; G2
10) ANS:
homogeneous
DIF: 1
REF: Page Ref: 14.6
PTS: 1
OBJ: 14.7; G2
11) ANS:
heterogeneous
DIF: 2
REF: Page Ref: 14.7
PTS: 1
OBJ: 14.7; G2
12) ANS:
adsorption
DIF: 2
REF: Page Ref: 14.7
PTS: 1
OBJ: 14.7; G2
13) ANS:
absorption
DIF: 1
REF: Page Ref: 14.7
PTS: 1
OBJ: 14.7; G2
DIF: 3
REF: Page Ref: 14.7
PTS: 1
DIF: 1
REF: Page Ref: 14.2
PTS: 1
DIF: 1
REF: Page Ref: 14.2
PTS: 1
DIF: 1
REF: Page Ref: 14.3
TRUE/FALSE
1) ANS:
OBJ:
2) ANS:
OBJ:
3) ANS:
OBJ:
F
14.2; G2
F
14.2; G2
T
14.3; G2
3
ID: A
4) ANS:
OBJ:
5) ANS:
OBJ:
6) ANS:
OBJ:
7) ANS:
OBJ:
8) ANS:
OBJ:
9) ANS:
OBJ:
F
14.3; G2
T
14.3; G2
T
14.4; G2
F
14.4; G2
T
14.6; G2
T
14.7; G2
PTS: 1
DIF: 1
REF: Page Ref: 14.3
PTS: 1
DIF: 1
REF: Page Ref: 14.3
PTS: 1
DIF: 1
REF: Page Ref: 14.4
PTS: 1
DIF: 1
REF: Page Ref: 14.4
PTS: 1
DIF: 1
REF: Page Ref: 14.6
PTS: 1
DIF: 1
REF: Page Ref: 14.7
4
Chapter 14 Practice test [Answer Strip]
A
_____
4)
A
_____
7)
ID: A
E 11)
_____
A
_____
1)
A 12)
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B 14)
_____
D
_____
5)
D
_____
8)
A 15)
_____
C
_____
9)
A 16)
_____
D
_____
6)
C 13)
_____
E
_____
2)
C 17)
_____
D 10)
_____
E
_____
3)
Chapter 14 Practice test [Answer Strip]
B 18)
_____
C 22)
_____
A 23)
_____
ID: A
A 27)
_____
E 28)
_____
A 24)
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B 19)
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A 29)
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C 20)
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B 25)
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D 30)
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F
_____
1)
F
_____
2)
B 21)
_____
A 31)
_____
T
_____
3)
F
_____
4)
A 26)
_____
T
_____
5)
T
_____
6)
F
_____
7)
T
_____
8)
T
_____
9)

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