Kinetics Problem Set

This problem set was developed by S.E. Van Bramer for Chemistry 145 at Widener University.

Data from Zumdahl, Chemistry,

Reaction Rates and Rate laws for the following reaction:

NO(g) + O3 (g) -> NO2(g) + O2(g)

Given the following data:

[O3] = 1.0*1014molecules cm-3
Time [NO]
0 ms 6.0*108
100 5.0*108
500 2.4*108
700 1.7*108
1000 9.9*107

[NO] = 2.0*1014 molecules cm-3
Time [O3]
0 1.0*1010
50 8.4*109
100 7.0*109
200 4.9*109
300 3.4*109

  1. Using the data above:
    1. Graph each data set.

    2. Graph ln[] vs time.

    3. Determine the average rate for the reaction, between each data point.
    4. Use your graph to determine the instentaneous reaction rate at 250 ms.
    5. Given that the reaction is first order in NO and in O3, determine the rate constant using your calculated rate for each set of data points
    6. Use the ln[] vs time graph to determine the rate constant.
    7. What is the overall rate law?
    8. Convert the units of the rate constant to moles, liters, and seconds.

  2. Given the following kinetics data for the above reaction:

    T (K) k(L mole-1 sec-1)
    195 1.08 * 109
    230 2.95 * 109
    260 5.42 * 109
    298 12.0 * 109
    369 35.5 * 109

    1. Graph this data as ln(k) vs 1/T.

    2. Determine the activation energy and the preexponential factor from the graph.
    3. What is the rate constant at 150 K?

  3. Catalysis, Temperature, and the Arrhenius equation

      For the above reaction mechanism with several additional steps as shown below:

      Step 1: NO + O3 -> NO2 + O2

      Step 2: NO2 + O -> NO + O2

      Overall: O3 + O -> 2 O2

    1. Which species is a catalyst?
    2. Which species is an intermediate?
    3. How does this catalyst effect the rate of the reaction shown below. Ea = 11.9 kJ for the catalyzed reaction and Ea = 14.0 kJ for the uncatalyzed reaction. Calculate the change in the reaction rate at 200, 250, and 300 K

      O3 + O -> 2 O2

    4. Draw an energy level diagram for this reaction, with and without catalysis.
    5. For the catalytic destruction of O3 by Cl Ea = 2.1 kJ, Compare the reaction rate for the uncatalyzed reaction and the Cl catalyzed reaction at 250 K.

Please send comments or suggestions to svanbram@science.widener.edu

Scott Van Bramer
Department of Chemistry
Widener University
Chester, PA 19013

© copyright 1996, S.E. Van Bramer
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Last Updated: Saturday, May 18, 1996