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Page 1: Chem Quiz 11
Page 2: Chem Quiz 11
Page 3: Chem Quiz 11
Page 4: Chem Quiz 11
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Page 8: Chem Quiz 11

1.

The rate of a reaction may be expressed as the disappearance of reactants with respect to time.

Student Response Value Correct Answer Feedback

1. False

 2.True 100%

Score: 1/1

2.

The rate law for the reaction 3A → C is Rate = 4.36 × 10¯2 L mol¯1 hr¯1[A]2 What is the half-life for the reaction if the initial concentration of A is 0.250 M?

Student Response Value Correct Answer Feedback

A. 15.9 hr

 B.

0.0629 hr 0%

C. 91.7 hr

D. 23.9 hr

E. 0.0109 hr

Score: 0/1

3.

Refer to the Figure below and estimate the instantaneous rate of the ozone decomposition to O2 reaction at 40 hours into the reaction, in atm/hr.

Student Response Value Correct Answer Feedback

A. 1.94

Page 9: Chem Quiz 11

B. 38.5

 C.

0.263 0%

D. 0.0102

E. 1.05

Score: 0/1

4.

Initial rate data below were obtained for the following reaction:

A (g) + 2 B (g) → C (g) + D (g)

 What is the rate law for the reaction? Note: The "?" in the rate values should be "x" (times).

Student Response Value Correct Answer Feedback

A. rate = k [A]

B. rate = k [A][B]

 C.

rate = k [A]2[B] 100%

D. rate = k [A]2[B]3

E. rate = k [A][B]2

Score: 1/1

5.

A reaction is second-order with respect to the reactant R. Which of the following plots will produce a straight line?

Student Response Value Correct Answer Feedback

A. [R] vs. 1/time

 B.

1/[R] vs. time 100%

Page 10: Chem Quiz 11

C. [R]2 vs. time

D. 1/[R]2 vs. time

E. ln[R] vs. time

Score: 1/1

6.

A reaction mechanism is a collection of elementary steps.

Student Response Value Correct Answer Feedback

1. False

 2.True 100%

Score: 1/1

7.

The rate law for the reaction 3A → 2B is rate = k[A] with a rate constant of 0.0447 hr¯1. What is the half-life of the reaction?

Student Response Value Correct Answer Feedback

A. 0.0224 hr

B. 0.0645 hr

 C.

15.5 hr 100%

D. 22.4 hr

E. 44.7 hr

Score: 1/1

8.

The gas-phase reaction CH3NC → CH3CN has been studied in a closed vessel, and the rate equation was found to be: Rate = −Δ[CH3NC]/Δt = k[CH3NC]. Which one of the following actions is least likely to cause a change in the rate of the reaction?

Student Response Value Correct Answer Feedback

A. lowering the temperature

B. adding a catalyst

C. using a larger initial

Page 11: Chem Quiz 11

amount of CH3NC in the same vessel

 D.using a bigger vessel, but the same initial amount of CH3NC

0%

E. continuously removing CH3CN as it is formed

Score: 0/1

9.

A rate constant obeys the Arrhenius equation, the factor A being 2.2 × 1013 s¯1 and the activation energy being 150. kJ mol¯1. What is the value of the rate constant at 227°C, in s¯1?

Student Response Value Correct Answer Feedback

 A.2.1 × 1013s¯1 0%

B. 6.7 × 10¯22 s¯1

C. 1.5 × 1011s¯1

D. 4.7 × 10¯3s¯1

E. None of these choices is correct.

Score: 0/1

10.

Lowering the activation energy of a reaction will increase the rate of reaction by:

Student Response Value Correct Answer Feedback

1. removing potential energy from the reactants.

2. spontaneously increasing the amount of reactants.

3. packing the created products in a favored arrangement.

Page 12: Chem Quiz 11

 4.providing a new reaction mechanism.

100%

Score: 1/1

1.

The decomposition of hydrogen peroxide (H2O2) into O2(g) and liquid H2O produced the following data:

time (min) 10.00 20.00 30.00 40.00 60.00O2 volume (mL) 67.2 147 304 628 2769

What is the average rate in mL/min for the third ten-minute period of the reaction?

Student Response

Value Correct Answer Feedback

1. 7.98 mL/min

2. 10.1 mL/min

 3. 15.7 mL/min 100%

4. 6.72 mL/min

Score: 1/1

2.

The rate law for the reaction 3A → C is Rate = 4.36 × 10¯2 L mol¯1 hr¯1[A]2 What is the half-life for the reaction if the initial concentration of A is 0.250 M?

Student Response

Value Correct Answer Feedback

A. 0.0629 hr

B. 23.9 hr

C. 15.9 hr

D. 0.0109 hr

 E. 91.7 hr 100%

Page 13: Chem Quiz 11

Score: 1/1

3.

Which of the following statements would be correct regarding the following reaction?

2 H2 (g) + O2 (g) → 2 H2O (g)

Student Response

Value Correct Answer Feedback

 A. The rate of O2disappearance is twice the rate of H2disappearance.

0%

B. The rate of H2disappearance is twice the rate of O2disappearance.

C. The rate of H2O disappearance is twice the rate of O2disappearance.

D. The rate of H2O appearance is equal to the rate of O2disappearance.

E. The rate of H2disappearance is equal to the rate of O2disappearance.

Score: 0/1

4.

The rate equation for the decomposition of H2O2 is rate = k [H2O2] [I−]. What are the units of the rate constant, k?

Page 14: Chem Quiz 11

Student Response

Value Correct Answer Feedback

A. L− mol−1time−1

 B. mol L−1time−1 0%

C. L mol−1time−1

D. L mol−1 time

E. time−1

Score: 0/1

5.

When the reaction A → B + C is studied, a plot 1/[A]t vs. time gives a straight line with a positive slope. What is the order of the reaction?

Student Response

Value Correct Answer Feedback

A. zero

B. first

 C. second 100%

D. third

E. More information is needed to determine the order.

Score: 1/1

6.

The rate of a reaction is determined by the rate of the fastest step in the mechanism.

Student Response Value Correct Answer

False 100% False

Score: 1/1

Page 15: Chem Quiz 11

7.

Cyclopropane is converted to propene in a first-order process. The rate constant is 5.4 × 10¯2 hr¯1. If the initial concentration of cyclopropane is 0.150 M, what will its concentration be after 22.0 hours?

Student Response

Value Correct Answer Feedback

A. 0.105 M

 B. 0.0457 M 100%

C. 0.127 M

D. 0.492 M

E. None of these choices is correct.

Score: 1/1

8.

The greater the energy of activation, Ea, the faster will be the reaction.

Student Response Value Correct Answer

False 100% False

Score: 1/1

9.

A reaction has an activation energy of 195.0 kJ/mol. When the temperature is increased from 200.°C to 220.°C, the rate constant will increase by a factor of:

Student Response

Value Correct Answer Feedback

A. 1.1

B. 4.3 × 104

C. 3.2

 D. 7.5 100%

Page 16: Chem Quiz 11

E. None of these choices is correct.

Score: 1/1

10.

The number of molecules that can react on a catalyst binding site per unit time is known as the ______ number. Enter your answer in lower case.

Student Response Value Correct Answer

1. turnover 100% Equals

Score: 1/1

1.

The decomposition of hydrogen peroxide (H2O2) into O2(g) and liquid H2O produced the following data:

time (min) 10.00 20.00 30.00 40.00 60.00O2 volume (mL) 67.2 147 304 628 2769

What is the average rate in mL/min for the third ten-minute period of the reaction?

Student Response

Value Correct Answer Feedback

1. 6.72 mL/min

2. 10.1 mL/min

 3. 15.7 mL/min 100%

4. 7.98 mL/min

Score: 1/1

2.

If a reaction is zero order with respect to [B], tripling the concentration of [B] will result in:

Page 17: Chem Quiz 11

Student Response

Value Correct Answer Feedback

1. a tripling of the rate

2. a nine-fold increase in rate

 3. no change in the rate of reaction

100%

4. a four-fold increase in rate

Score: 1/1

3.

In the reaction 2A + B → 2C + D, - [A]/ t is found to be 5.0 M Δ Δ ∙ min−1. What is the rate of reaction of B?

Student Response

Value Correct Answer Feedback

A. 5.0

B. 10

C. 75

 D. 2.5 100%

E. Additional information is required.

Score: 1/1

4.

Initial rate data were obtained for the following reaction:

2 A (g) + B (g) → C (g) + D (g)

Page 18: Chem Quiz 11

What is the order with respect to reactant B?Please note that "?" in rate values should be "x" (times).

Student Response

Value Correct Answer Feedback

A. 0

B. 1

 C. 2 100%

D. 3

E. 4

Score: 1/1

5.

For a 1st order reaction, a plot of concentration with respect to time produces a plot that is:

Student Response

Value Correct Answer Feedback

1. linear; m = 0

 2. linear 0%

3. non-linear

4. parabolic

Score: 0/1

6.

A transition state is a species (or state) corresponding to an energy maximum on a reaction energy diagram.

Student Response Value Correct Answer

True 100% True

Score: 1/1

Page 19: Chem Quiz 11

7.

A reactant R is being consumed in a first-order reaction. What fraction of the initial R is consumed in 4.0 half-lives?

Student Response

Value Correct Answer Feedback

 A. 0.063 0%

B. 0.75

C. 0.87

D. 0.94

E. 0.13

Score: 0/1

8.

Raising the temperature of a reaction elevates the rate of reaction by:

Student Response

Value Correct Answer Feedback

1. increasing the energy of activation

2. creating more molecules in the reaction.

3. decreasing the entropy of the system.

 4. increasing the number of molecules moving at a speed sufficiently high enough to produce a

100%

Page 20: Chem Quiz 11

reactive collision.

Score: 1/1

9.

If the activation energy for the forward reaction is greater than the activation energy for the reverse reaction, the reaction is

Student Response

Value Correct Answer Feedback

A. faster in the forward direction.

B. faster in the reverse direction.

C. exothermic.

 D. endothermic. 100%

E. spontaneous

Score: 1/1

10.

A reaction which is catalyzed has a higher activation energy than the uncatalyzed reaction so it proceeds at a higher rate.

Student Response Value Correct Answer

False 100% False

Score: 1/1

 

Page 21: Chem Quiz 11