1. Principles & Modern Applications
General Chemistry
Principles & Modern Applications
9th Edition
Petrucci/Harwood/Herring/Madura
Chapter 14
Chemical Kinetics
Dr. Travis D. Fridgen
Memorial University of Newfoundland
© 2007 Pearson Education

2. A particular first order reaction was monitored over a period of time
A particular first order reaction was monitored over a period of time. The figure to the right summarizes the experimental results where each sphere represents 3.0 mol L-1. The average reaction rate is (do not use a calculator),
10 : 00 : 00
10 : 01 : 30
mol L-1 s-1
mol L-1 s-1
s-1
mol L-1 s-1
s-1

3. A particular first order reaction was monitored over a period of time
A particular first order reaction was monitored over a period of time. The figure to the right summarizes the experimental results where each sphere represents 3.0 mol L-1. The average reaction rate is (do not use a calculator),
10 : 00 : 00
10 : 01 : 30
mol L-1 s-1
mol L-1 s-1
s-1
mol L-1 s-1
s-1

4. Consider the following reaction,
whose rate can be expressed as
Equivalent expressions are…

5. Consider the following reaction,
whose rate can be expressed as
Equivalent expressions are…

6. ln [X] t
In the diagram to the right is a plot of the concentrations of all reactants and products as a function of time for a particular reaction.
Which of the following statements is correct?
1. The reaction is second order.
2. The blue curve represents the time dependence on a particular product.
3. The rate constant for the reaction could have units of s-1.
4. The product represented by the green line is produced almost twice as fast as the product represented by the red line.
5. Cannot tell with the information given.

7. ln [X] t
In the diagram to the right is a plot of the concentrations of all reactants and products as a function of time for a particular reaction.
Which of the following statements is correct?
1. The reaction is second order.
2. The blue curve represents the time dependence on a particular product.
3. The rate constant for the reaction could have units of s-1.
4. The product represented by the green line is produced almost twice as fast as the product represented by the red line.
5. Cannot tell with the information given.

8. In this question, two reactions are considered.
ln [X] t
Reaction A has a rate constant which is equal to 16.2 L mol-1 s-1. A plot relating the concentrations of the reactants and products with time is plotted for reaction B to the right.
Reaction A is first order and Reaction B is second order.
2. Reaction A is second order and Reaction B is first order.
3. Both reactions are first order.
4. Both reactions are second order.

9. In this question, two reactions are considered.
ln [X] t
Reaction A has a rate constant which is equal to 16.2 L mol-1 s-1. A plot relating the concentrations of the reactants and products with time is plotted for reaction B to the right.
Reaction A is first order and Reaction B is second order.
2. Reaction A is second order and Reaction B is first order.
3. Both reactions are first order.
4. Both reactions are second order.

10. 81.7 s
Some data for the decomposition of dinitrogen pentoxide are plotted to the right. Which of the following statements is correct?
1. The rate constant is 81.7 s.
2. The rate constant is
3. The units of the rate constant are s.
4. The reaction is first order in N2O5.
5. The reaction is third order in N2O5.

11. 81.7 s
Some data for the decomposition of dinitrogen pentoxide are plotted to the right. Which of the following statements is correct?
1. The rate constant is 81.7 s.
2. The rate constant is
3. The units of the rate constant are s.
4. The reaction is first order in N2O5.
5. The reaction is third order in N2O5.

12. 1. 2.
A+B
Energy
reaction coordinate
A+B
X+Y
The reaction between A and B is determined to be a fairly fast reaction and slightly exothermic. Which of the following potential energy surfaces fit this description?
Energy
X+Y
reaction coordinate 3. 4.
Energy
reaction coordinate
A+B
X+Y
Energy
reaction coordinate
A+B
X+Y

13. 1. 2.
A+B
Energy
reaction coordinate
A+B
X+Y
The reaction between A and B is determined to be a fairly fast reaction and only slightly exothermic. Which of the following potential energy surfaces fit this description?
Energy
X+Y
reaction coordinate 3. 4.
Energy
reaction coordinate
A+B
X+Y
Energy
A+B
X+Y
reaction coordinate

14. A particular reaction was found to have forward and reverse activation energies of 60 and 140 kJ mol-1, respectively. The enthalpy change for the reaction is, (do not use a calculator) R
Energy
1. DH = 60 kJ mol-1
2. DH = -60 kJ mol-1 P
3. DH = 80 kJ mol-1
4. DH = -80 kJ mol-1
reaction coordinate
5. DH = 140 kJ mol-1

15. A particular reaction was found to have forward and reverse activation energies of 60 and 140 kJ mol-1, respectively. The enthalpy change for the reaction is, (do not use a calculator) R
Energy
1. DH = 60 kJ mol-1
2. DH = -60 kJ mol-1 P
3. DH = 80 kJ mol-1
4. DH = -80 kJ mol-1
reaction coordinate
5. DH = 140 kJ mol-1

16. The apparent activation energy for the chemical reactions which produce light in a firefly is 50 kJ mol-1. How many times slower would you expect the firefly to blink if you cooled down its surroundings from 300 K to 270 K? (You may require your calculator)
1. ~0.1 x
2. ~0.3 x
3. ~3 x
4. ~9 x
5. ~1000 x

17. The apparent activation energy for the chemical reactions which produce light in a firefly is 50 kJ mol-1. How many times slower would you expect the firefly to blink if you cooled down its surroundings from 300 K to 270 K? (You may require your calculator)
1. ~0.1 x
2. ~0.3 x
3. ~3 x
4. ~9 x
5. ~1000 x

18. The exothermic iodide catalyzed decomposition of peroxide was determined to occur via two separate steps in which the first step is the rate determining step. Which of the following three potential energy diagrams best summarizes these findings. + 1. 2. 3. R R R
Energy
Energy
Energy P P P
reaction coordinate
reaction coordinate
reaction coordinate

19. The exothermic iodide catalyzed decomposition of peroxide was determined to occur via two separate steps in which the first step is the rate determining step. Which of the following three potential energy diagrams best summarizes these findings. +
Energy
reaction coordinate R P 1.
Energy
reaction coordinate R P 2.
Energy
reaction coordinate R P 3.

20. The mechanism for the reaction could be
A schematic of the potential energy diagram for the reaction of iodine with hydrogen is shown to the right. Based on this diagram, which of the following statements is incorrect.
Energy
reaction coordinate 2 +
The mechanism for the reaction could be
2. Since iodine atoms are intermediate species, their concentration is undetectable during the course of the reaction.
3. The second step is the rate-determining step.
4. The overall reaction is exothermic.

21. The mechanism for the reaction could be
A schematic of the potential energy diagram for the reaction of iodine with hydrogen is shown to the right. Based on this diagram, which of the following statements is incorrect.
Energy
reaction coordinate 2 +
The mechanism for the reaction could be
2. Since iodine atoms are intermediate species, their concentration is undetectable during the course of the reaction.
3. The second step is the rate-determining step.
4. The overall reaction is exothermic.

22. is A mechanism for the following reaction slow fast
Beginning with two moles of NO2 and 1 mole of F2, which of the following diagrams best represents the mechanism? 1.
[X] t
[NO2F]
[F]
[NO2]
[F2] 2. t
[NO2F]
[F]
[NO2]
[F2]
[X] 3. t
[NO2F]
[F]
[NO2]
[F2]
[X]

23. is A mechanism for the following reaction slow fast
Beginning with two moles of NO2 and 1 mole of F2, which of the following diagrams best represents the mechanism? 1.
[X] t
[NO2F]
[F]
[NO2]
[F2] 2. t
[NO2F]
[F]
[NO2]
[F2]
[X] 3. t
[NO2F]
[F]
[NO2]
[F2]
[X]

24. The Lindemann/Hinshelwood mechanism for a unimolecular reaction is given below.
Which of the following plots represents the pressure dependence of the rate constant? 1. 2. PM
rate PM
rate
A steady-state analysis of the mechanism yields the following
at low pressure 3. 4. PM
rate PM
rate
at high pressure

25. The Lindemann/Hinshelwood mechanism for a unimolecular reaction is given below.
Which of the following plots represents the pressure dependence of the rate constant? 1. 2. PM
rate
A steady-state analysis of the mechanism yields the following
rate PM
at low pressure 3. 4. PM
rate PM
rate
at high pressure

26. Energy
reaction coordinate 1.
A+B
X+Y 2.
Energy
A+B
X+Y
In which diagram to the right does the dashed line best represent the catalyzed version of the reaction’s potential energy profile?
reaction coordinate
Energy
reaction coordinate
A+B
X+Y 3. 4.
Energy
reaction coordinate
A+B
X+Y

27. Energy
reaction coordinate 1.
A+B
X+Y 2.
Energy
A+B
X+Y
In which diagram to the right does the dashed line best represent the catalyzed version of the reaction’s potential energy profile?
reaction coordinate
Energy
reaction coordinate
A+B
X+Y 3. 4.
Energy
reaction coordinate
A+B
X+Y