Name: ___________________________________    Date: ______________



1.
Nitrogen monoxide reacts with bromine at elevated temperatures according to the equation
2 NO(g) + Br2(g) → 2 NOBr(g)
In a certain reaction mixture the rate of formation of NOBr(g) was found to be 4.50 x 10-4 mol L-1 s-1. What is the rate of consumption of Br2(g)?
A.
4.50 x 10-4 mol L-1 s-1
B.
2.25 x 10-4 mol L-1 s-1
C.
9.00 x 10-4 mol L-1 s-1
D.
2.12 x 10-4 mol L-1 s-1
E.
2.03 x 10-3 mol L-1 s-1


2.
In a particular study of the reaction described by the equation,
2 CH4O(g) + 3 O2(g) → 2 CO2(g) + 4 H2O(g),
the rate of consumption of O2(g) is 0.400 mol L-1 s-1. What is the rate of consumption of CH4O(g)?
A.
0.200 mol L-1 s-1
B.
0.267 mol L-1 s-1
C.
0.333 mol L-1 s-1
D.
0.400 mol L-1 s-1
E.
0.600 mol L-1 s-1


3.
The rate of a chemical reaction in solution can be measured in the units
A.
L2 mol-1 s-1
B.
mol L-1 s-1
C.
s-2
D.
mol s L-1
E.
sec L-1 mol-1


4.
A reaction has the rate law, rate = k[A][B]2. Which change will cause the greatest increase in the reaction rate?
A.
decreasing the temperature without changing the concentrations
B.
doubling the concentration of B
C.
quadrupling the concentration of A
D.
tripling the concentration of B
E.
doubling the concentration of A


5.
The reaction, 2 NO(g) + O2(g) → 2 NO2(g), was found to be first order in each of the two reactants and second order overall. The rate law is therefore
A.
rate = k[NO]2
B.
rate = k[NO][O2]
C.
rate = k[NO2]2[NO]-2[O2]-1/2
D.
rate = k[NO]2[O2]2
E.
rate = k([NO][O2])2


6.
A reaction has the rate law, rate = k[A][B]2. What is the overall order of the reaction?
A.
2nd
B.
4th
C.
1st
D.
3rd
E.
0


7.
A reaction has the rate law, rate = k[A][B]2. What is the order of the reaction with respect to B?
A.
2nd
B.
4th
C.
1st
D.
3rd
E.
0


8.
For the reaction, 2 XO + O2 → 2 XO2, data obtained from measurement of the initial rate of reaction at varying concentrations are given below.
 
Experiment
[XO]
[O2]
Rate (mmol L-1 s-1 )
 
1
0.010
0.010
2.5
 
2
0.010
0.020
5.0
 
3
0.030
0.020
45.0
The rate law is therefore
A.
rate = k[XO]2 [O2]
B.
rate = k[XO][O2]2
C.
rate = k[XO][O2]
D.
rate = k[XO]2 [O2]2
E.
rate = k[XO]2/[O2]2


9.
For the reaction, 2 M + 2 N → 2 P + Q, studies on how the initial rate of the reaction varied with concentration were carried out. Some data is given below.
 
Experiment
[M]
[N]
Rate (mol L-1 s-1)
 
1
0.100
0.100
0.000230
 
2
0.100
0.200
0.000920
 
3
0.200
0.200
0.000920
 
A.
the rate law is therefore: rate = k[N]2
B.
the rate law is therefore: rate = k[M][N]2
C.
the rate law is therefore: rate = k[M][N]
D.
the rate law is therefore: rate = k[M]2
E.
the rate law is therefore: rate = k[M]2[N]2


10.
For the reaction, A + 2 B → C + 2 D, some measurements of the initial rate of reaction at vary ing concentration gave the following data.
 
Experiment
[A]
[B]
Rate (mol L-1 s-1)
 
1
0.100
0.200
0.000360
 
2
0.150
0.200
0.000540
 
3
0.150
0.250
0.001055
 
A.
the rate law is therefore: rate = k[A]2[B]
B.
the rate law is therefore: rate = k[A][B]2
C.
the rate law is therefore: rate = k[A]2[B]2
D.
the rate law is therefore: rate = k[A][B]
E.
the rate law is therefore: rate = k[A][B]3


11.
Nitric oxide reacts with bromine at elevated temperatures according to the equation
2 NO(g) + Br2(g) → 2 NOBr(g)
The experimental rate law is rate = k[NO][Br2]. In a certain reaction mixture the rate of formation of NOBr(g) was found to be 4.50 x 10-4 mol L-1 s-1. Which unit below is the correct unit for the rate constant in this case?
A.
mol L-1 s-1
B.
s-1
C.
mol2 L-2 s-1
D.
mol-1 L s-1
E.
mol-2 L2 s-1


12.
For the reaction, 3 B + C → E + 2 F, initial rate measurements were carried out and data for three runs are shown below
 
Experiment
[B]
[C]
Rate (mol L-1 s-1)
 
1
0.100
0.250
0.000250
 
2
0.200
0.250
0.000500
 
3
0.100
0.500
0.00100
The rate law, therefore, is
A.
rate = k[B]3[C]
B.
rate = k[B][C]
C.
rate = k[B]2[C]2
D.
rate = k[B]2[C]
E.
rate = k[B][C]2


13.
Given the reaction,
If we try rate = k[A]q[B]r for a generic rate law statement, which one of the statements below is false?
A.
The exponents q and r are often integers.
B.
The exponent q and r must be determined experimentally.
C.
The exponents q and r are equal to the coefficients a and b, respectively.
D.
The overall order of the reaction is q + r.
E.
The symbol k represents the rate constant.


14.
The reaction, A + 2 B → products, was studied. The reagents A and B were mixed and the time interval until a certain quantity of product C accumulated was measured. The data were obtained
 
Experiment
[A]
[B]
Time (secs)
 
1
0.100
0.140
25
 
2
0.050
0.140
50
 
3
0.100
0.070
100
We can conclude that
A.
the reaction is first order with respect to substance A
B.
the reaction is zero order with respect to substance A
C.
the reaction is onehalf order with respect to substance A
D.
the reaction is second order with respect to substance A
E.
the reaction is third order with respect to substance B


15.
The data below were obtained in a study on how the rate of a reaction was affected by the concentration of its reactants.
 
Experiment
[A]
[B]
[C]
Rate (mol L-1 hr-1)
 
1
0.200
0.100
0.600
5.0
 
2
0.200
0.400
0.400
80.0
 
3
0.600
0.100
0.200
15.0
 
4
0.200
0.100
0.200
5.0
 
5
0.200
0.200
0.400
20.0
From this data
A.
The order of the reaction with respect to C cannot be determined.
B.
The reaction is second order with respect to C.
C.
The reaction is zero order with respect to C.
D.
The reaction is first order with respect to C.
E.
The order of the reaction with respect to C is minus one.


16.
Given these data in a study on how the rate of a reaction was affected by the concentration of the reactants,
 
Experiment
[A]
[B]
[C]
Rate, mol L-1 hr-1
 
1
0.200
0.100
0.600
5.0
 
2
0.200
0.400
0.400
80.0
 
3
0.600
0.100
0.200
15.0
 
4
0.200
0.100
0.200
5.0
 
5
0.200
0.200
0.400
20.0
From this data
A.
the reaction is zero order with respect to B.
B.
the reaction is first order with respect to B.
C.
the reaction order for B cannot be determined.
D.
the reaction is second order with respect to B.
E.
the reaction order for B is minus one.


17.
Given these data in a study on how the rate of a reaction was affected by the concentration of the reactants,
 
Experiment
[A]
[B]
[C]
Rate (mol L-1 hr-1)
 
1
0.200
0.100
0.600
5.0
 
2
0.200
0.400
0.400
80.0
 
3
0.600
0.100
0.200
15.0
 
4
0.200
0.100
0.200
5.0
 
5
0.200
0.200
0.400
20.0
From this data
A.
the reaction is first order with respect to A.
B.
the reaction is second order with respect to A.
C.
the reaction is zero order with respect to A.
D.
the reaction order for A is minus one (Rate proportional to 1/[A]).
E.
the reaction order for A cannot be determined from just this data alone.


Reference: Ref 13-1

18.
Graph a can best be described as
A.
Zero order rate process.
B.
First order rate process.
C.
Second order rate process.
D.
B or C
E.
A or C


Reference: Ref 13-1

19.
The instantaneous rate at any point in graph b can be found by
A.
taking the average of all rates found every 100 s
B.
drawing a line tangent to the curve at the initial and final times, and then averaging
C.
drawing a line tangent to the curve at that point
D.
subtracting the final concentration from the initial concentration and dividing by the time interval
E.
subtracting the final time from the initial time and dividing by the concentration


Reference: Ref 13-1

20.
We can determine the reaction order from graph b by
A.
doing nothing
B.
plotting 1/[A] vs. time and getting a straight line
C.
plotting ln[A] vs. time and getting a straight line
D.
plotting the square root of concentration vs. time and getting a straight line
E.
B and C


21.
In a first order reaction with only one reagent, the reaction was started with a concentration of reactant equal to 0.0800 M. After exactly two hours, the concentration had fallen to 0.0400 M. What is the molarity after exactly six hours?
A.
0.0000 M
B.
0.0100 M
C.
0.0150 M
D.
0.0200 M
E.
0.0300 M


22.
The half-life of a chemical reaction was found to be independent of the quantity of reactant which was employed. The reaction is therefore
A.
possibly first order
B.
definitely first order
C.
zero order
D.
possibly second order
E.
definitely second order


23.
The decomposition of an aldehyde solution in carbon tetrachloride is a first order reaction with a rate constant of 1.20 x 10-3 min-1. If we start with [aldehyde] = 0.0500 M, what will the concentration be 150 minutes later?
A.
0.00900 M
B.
0.0418 M
C.
0.00926 M
D.
0.00499 M
E.
0.000333 M


24.
The rate constant for a first order decomposition reaction is 0.0111 min-1. What is the half-life of the reaction?
A.
111 min
B.
62.4 min
C.
5000 sec
D.
31.25 min
E.
27.1 min


25.
Given a reaction, 2 A + B → P, for which the rate law is rate = k[A]. Which equation or statement is true?
A.
[A] = 1/kt
B.
ln[A] = k/t
C.
1/[A] = kt
D.
the half-life is 0.693/k
E.
e[A] = -kt


26.
In a first order reaction, what fraction of the reactant will remain after 4 half-lives?
A.
1/16
B.
1/8
C.
1/9
D.
1/4
E.
1/3


27.
The reaction of substance A with substance C was carefully studied under conditions where the [C] remained essentially constant. The graph of [A] vs. time gave a straight line while the graph of ln[A] vs. time and that of 1/[A] vs. time both gave curves.
A.
The reaction is therefore zero order with respect to A.
B.
The reaction is therefore one-half order with respect to A.
C.
The reaction is therefore first order with respect to A.
D.
The reaction is therefore second order with respect to A.
E.
The reaction is therefore third order with respect to A.


28.
A variable which has no effect on the rate of a chemical reaction under any circumstances is
A.
energy of activation.
B.
a catalyst.
C.
the concentration of the reactants.
D.
the temperature.
E.
the standard enthalpy of reaction for the system.


29.
For a one step reaction, the activation energy for the forward reaction is 40.0 kJ mol-1, and the enthalpy of reaction is -20.0 kJ mol-1. Calculate the activation energy for the reverse reaction.
A.
+60.0 kJ mol-1
B.
-20.0 kJ mol-1
C.
-1200 kJ kJ mol-1
D.
+20.0 kJ kJ mol-1
E.
+1200 kJ kJ mol-1


30.
For a chemical reaction, the rate constant at 250.0 °C is 0.00383 s-1, and the activation energy is 22.40 kJ mol-1. Calculate the value of the rate constant at 335.0 °C.
A.
0.00513 s-1
B.
0.00946 s-1
C.
0.00787 s-1
D.
0.0224 s-1
E.
0.000640 s-1


31.
The rate constant for a certain chemical reaction is 0.00250 L mol-1 s-1 at 25.0 C and 0.0125 L mol-1 s-1 at 50.0 °C. What is the activation energy for the reaction, expressed in kJ mol-1?
A.
25.1 kJ mol-1
B.
51.6 kJ mol-1
C.
37.6 kJ mol-1
D.
45.3 kJ mol-1
E.
60.3 kJ mol-1


32.
Suppose the reaction: A + B → D followed the mechanism
 
A + BC
(fast)
 
C → D
(slow)
The rate law for the reaction would be
A.
rate = k[A]
B.
rate = k[A]2
C.
rate = k[A][B]
D.
rate = k[A][B]/[D]
E.
rate = k[A][B][C]


33.
The reaction: A + 3 B → D + F was studied carefully and the following mechanism was finally determined.
 
A + BC      
(fast)
 
C + B → D + E  
(slow)
 
E + B → F      
(very fast)
The rate law for the reaction would therefore be
A.
rate = k[A]2[B]
B.
rate = k[A][B]2
C.
rate = k[C][B]
D.
rate = k[A][B]3
E.
rate = k[A][B]


34.
The reaction mechanism proposed for the decomposition of H2O2 is
                        H2O2 + I- → H2O + IO-             (slow)
                        H2O2 + IO- → H2O + O2 + I-    (fast)
Which statement is true?
A.
The reaction is second order with respect to I-.
B.
I- is an intermediate.
C.
The reaction is first order with respect to I-.
D.
IO- is a catalyst.
E.
The reaction is zero order with respect to I-.


35.
Which statement concerning the rate of a chemical reaction is false?
A.
It will be very rapid if the activation energy is large.
B.
It will be slow if one or more of the steps is slow.
C.
It may be inhibited sometimes by certain catalytic agents.
D.
It is dependent on temperature.
E.
It often increases when the concentrations of one of the reactants is increased.


36.
The reaction, A + 3 B → D + F was studied and the following mechanism was established:
 
A + BC
(fast)
 
C + B → D + E
(slow)
 
E + B → F      
(very fast)
The species, E, is properly described as
A.
an intermediate.
B.
a cofactor.
C.
a catalyst.
D.
an inhibitor.
E.
an enzyme.


37.
A catalyst alters the rate of a chemical reaction by
A.
providing an alternate pathway which has a different activation energy.
B.
changing the products formed in the reaction.
C.
changing the frequency of collisions between molecules.
D.
always providing a surface on which molecules react.
E.
changing the enthalpy of reaction for the reaction.


38.
Which statement is true concerning a negative catalyst?
A.
It lowers the energy of activation of the rate determining step.
B.
It increases the enthalpy of reaction.
C.
It never undergoes a chemical change at any time during a chemical reaction.
D.
It blocks the path with the highest energy of activation for the rate determining step.
E.
It blocks the path with the lowest energy of activation for the rate determining step.


39.
The nuclear transmutation reaction of X is a first order reaction. If the half-life of X is 188.5 hours, how much would a sample weighing 14.55 mg today weigh at the same time tomorrow? __________

Answer:


40.
What effect does a negative catalyst have on the value of the rate constant for a particular reaction? ____________

Answer:


41.
Nitric oxide reacts with bromine at elevated temperatures according to the equation,
2 NO(g) + Br2(g) → 2 NOBr(g).
The experimental rate law is: rate = k[NO][Br2]. The half-life of either of the reactant species is independent of its concentration and is equal to 0.693/k.
A. True
B. False


42.
The activation energy of a reaction is equal to the difference between the standard enthalpy of formation of the reactants and the standard enthalpy of formation of the products.
A. True
B. False


43.
A catalyst that lowers the activation energy of the forward reaction in a system to onehalf its uncatalyzed value will also lower the activation energy of the reverse reaction in the system to one-half its uncatalyzed value.
A. True
B. False


44.
Given this data from a study on how the rate of a reaction was affected by the concentration of the reactants
 
Experiment
[A]
[B]
[C]
Initial rate (mol L-1 hr-1)
 
1
0.200
0.100
0.600
5.0
 
2
0.200
0.400
0.400
80.0
 
3
0.600
0.100
0.200
15.0
 
4
0.200
0.100
0.200
5.0
 
5
0.200
0.200
0.400
20.0
 
A.
the rate constant is 2500 L2 mol-2 hr-1
B.
the rate constant is 208 L2 mol-2 hr-1
C.
the rate constant is 139 L2 mol-2 hr-1
D.
the rate constant is 2083 L2 mol-2 hr-1
E.
the rate constant is 6667 L2 mol-2 hr-1


45.
A nuclear transmutation reaction is a first order reaction. The mass of a sample was taken on three successive days at the same time. First day: 14.554 mg. Second day: 14.193 mg. Third day: 13.841 mg. What should the mass be at the same time on the fifth day? ______

Answer:


46.
The reaction, 2 NO2(g)   2 NO(g)   + O2(g), has a rate constant of 0.110 L mol-1 s-1 when the temperature is 450 °C. How long, in seconds, would it take for a sample of NO2 whose concentration is initially 0.355 M to decrease to 25.0 % of its original concentration at this temperature? _______

Answer:


47.
Suppose the reaction, 2 A + 2 B → 2 D + F followed the mechanism
 
A + BC + D
(fast)
 
A + C → E      
(slow)
 
E + B → D + F
(very fast)
The rate law for the reaction would be
A.
rate = k[A]2[B] / [D]
B.
rate = k[A][B][C]
C.
rate = k[A][B]/[D]
D.
rate = k[A]2[B]2
E.
rate = k[A][B]2


48.
What is the difference between homogenous and heterogeneous catalysis?

Answer:


49.
Why does increasing the temperature of a reaction mixture increase the reaction rate?

Answer:


50.
What are the factors which determine the rate of a chemical reaction?

Answer:



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