17) 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 (CH3NC) and 0 mol of product (CH3CN) in
the reaction vessel. After 25 min of reaction, 0.108 mol of reactant (CH3NC) 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
18) A reaction was found to be second order in carbon monoxide concentration. The rate of the reaction
________ if the [CO] is doubled, with everything else kept the same.
A) doubles
B) remains unchanged
C) triples
D) increases by a factor of 4
E) is reduced by a factor of 2
19) If the rate law for the reaction
2A + 3B → products
is first order in A and second order in B, then the rate law is rate = ________.
A) k[A][B]
B) k[A]2[B]3
C) k[A][B]2
D) k[A]2[B]
E) k[A]2[B]2
20) If the rate law for the reaction
2A + 3B → products
is second order in A and first order in B, then the rate law is rate = ________.
A) k[A][B]
B) k[A]2[B]3
C) k[A][B]2
D) k[A]2[B]
E) k[A]2[B]2
21) 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
22) The overall order of a reaction is 2. 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
23) The kinetics of the reaction below were studied and it was determined that the reaction rate increased
by a factor of 9 when the concentration of B was tripled. The reaction is ________ order in B.
A + B → P
A) zero
B) first
C) second
D) third
E) one-half
24) The kinetics of the reaction below were studied and it was determined that the reaction rate did not
change when the concentration of B was tripled. The reaction is ________ order in B.
A + B → P
A) zero
B) first
C) second
D) third
E) one-half
25) 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
26) A reaction was found to be zero 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
27) The order of the reaction in A is ________.
A) 1
B) 2
C) 3
D) 4
E) 0
28) The order of the reaction in B is ________.
A) 1
B) 2
C) 3
D) 4
E) 0
25
29) The overall order of the reaction is ________.
A) 1
B) 2
C) 3
D) 4
E) 0
30) The following reaction occurs in aqueous solution:
NH4+ (aq) + NO2– → N2 (g) + 2H2O (l)
The data below is obtained at 25 °C.
The order of the reaction in NH4+ is ________.
A) -2
B) -1
C) +2
D) +1
E) 0
31) For a first-order reaction, a plot of ________ versus ________ is linear.
A) ln [A]t,
B) ln [A]t, t
C) , t
D) [A]t, t
E) t,
32) The half-life of a first-order reaction is 13 min. If the initial concentration of reactant is 0.085 M, it takes
________ min for it to decrease to 0.055 M.
A) 8.2
B) 11
C) 3.6
D) 0.048
E) 8.4
33) 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
34) The graph shown below depicts the relationship between concentration and time for the following
chemical reaction.
The slope of this line is equal to ________.
A) k
B) –1/k
C) ln [A]o
D) -k
E) 1/k
35) The reaction below is first order in [H2O2]:
2H2O2 (l) → 2H2O (l) + O2 (g)
A solution originally at 0.600 M H2O2 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
36) A second-order reaction has a half-life of 18 s when the initial concentration of reactant is 0.71 M. The
rate constant for this reaction is ________ M-1s-1.
A) 7.8 × 10-2
B) 3.8 × 10-2
C) 2.0 × 10–2
D) 1.3
E) 18
37) 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
14.3 Algorithmic Questions
1) Of the following, only ________ is a valid unit for reaction rate.
A) M/s
B) mmol/mL
C) mol/g
D) g/L
E) atm/g
2) 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
3) Of the units below, ________ are appropriate for a third–order reaction rate constant.
A) M-2s-1
B) M s-1
C) s-1
D) M-1s-1
E) mol/L
29
4) The rate law for a reaction is
rate = k[A][B]
Which one of the following statements is false?
A) The reaction is first order overall.
B) The reaction is first order in A.
C) The reaction is first order in [B].
D) k is the reaction rate constant
E) If [A] is doubled, the reaction rate will increase by a factor of 2.
5) Nitrogen dioxide decomposes to nitric oxide and oxygen via the reaction:
2NO2 → 2NO + O2
In a particular experiment at 300 °C, [NO2] drops from 0.0143 to 0.00701 M in 261 s. The rate of
disappearance of NO2 for this period is ________ M/s.
A) 2.79 × 10-5
B) -8.16 × 10-5
C) 5.59 × 10-5
D) 1.40 × 10-5
E) 35,800
6) 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
7) The rate of disappearance of HBr in the gas phase reaction
2HBr (g) → H2 (g) + Br2 (g)
is 0.190 M s–1 at 150 °C. The rate of appearance of Br2 is ________ M s-1.
A) 2.63
B) 0.095
C) 0.0361
D) 0.380
E) 0.436
8) The rate of disappearance of HBr in the gas phase reaction
2HBr (g) → H2 (g) + Br2 (g)
is 0.140 M s-1 at 150 °C. The rate of reaction is ________ M s–1.
A) 3.57
B) 0.0700
C) 0.0196
D) 0.280
E) 0.0860
9) 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 appearance of CO2 is ________ M s-1.
A) 0.087
B) 0.043
C) 0.39
D) 0.20
E) 0.26
10) 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
11) Nitrogen dioxide decomposes to nitric oxide and oxygen via the reaction:
2NO2 (g) → 2NO (g) + O2 (g)
In a particular experiment at 300 °C, [NO2] drops from 0.0100 to 0.00800 M in 100 s. The rate of
appearance of O2 for this period is ________ M/s.
A) 1.0 × 10-5
B) 2.0 × 10-5
C) 4.0 × 10-5
D) 2.0 × 10-3
E) 4.0 × 10-3
12) At elevated temperatures, methylisonitrile (CH3NC) isomerizes to acetonitrile (CH3CN):
CH3NC (g) → CH3CN (g)
At the start of an experiment, there are 0.200 mol of reactant and 0 mol of product in the reaction vessel.
After 25 min, 0.121 mol of reactant (CH3NC) remain. There are ________ mol of product (CH3CN) in the
reaction vessel.
A) 0.022
B) 0.121
C) 0.200
D) 0.321
E) 0.079
13) A compound decomposes by a first-order process. If 13% of the compound decomposes in 60
minutes, the half-life of the compound is ________.
A) 299
B) 20
C) 12
D) –18
E) -5
14) 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