Kinetics Questions

1. The following data were obtained from initial rate studies of the reaction

2ICl(g) + H2(g) à I2(g) + 2HCl(g)                      

Experiment # [ICl], M [ H2], M Initial Rate, M/s
1 0.00150 0.00150 3.7 x 10^-7
2 0.00200 0.00300 9.6 x 10^-7
3 0.00300 0.00150 7.4 x 10^-7
4 0.00300 0.00450 2.2 x 10^-6

Deduce the experimental rate law for this reaction, including the numerical value (with units) for the rate constant.

 

2. Consider the reaction    2NH3(g) à N2(g) + 3H2(g) . If the rate of disappearance of  NH3   is 0.58 M/min, find the rate of appearance of  H2 .

3. For the reaction X + Y  à  Z , the rate is experimentally found to be second order with respect to Y and zero order with respect to X. Write the experimental rate law (in terms of k) for this reaction.                                                                                                     

4. The cis - trans isomerization reaction of 1,2-dichloroethylene proceeds with an energy of activation of 231 kJ/mole. The enthalpy change associated with the reaction is 4.2 kJ/mole. What is the value of the activation for the reverse reaction?

5. The decomposition of nitrogen dioxide   2NO2(g) à 2NO(g) + O2(g)
is a second order reaction. It takes 125 s for the concentration of  NO2 to go from 0.800M to 0.0104 M.  a) What is k for the reaction?    b)   What is the half-life of the reaction when its initial concentration is 0.500M?

6. The rate constant for the zero-order decomposition of HI on a gold surface is 0.050 M/s. How long will it take for the concentration of HI to drop from 1.00 M to 0.200 M?

7. The gas phase decomposition of ethyl chloride is a first order reaction. An experiment is started with 0.200 M ethyl chloride. Its concentration is found to be 0.197 M after 1.00 minute has elapsed. Calculate the first order rate constant and the half-life.

8. For the reaction   2H2(g) + 2NO(g) à N2(g) + 2H2O(g)

the experimental rate law is   RATE = k[NO]2[H2] . The following mechanism is proposed:

1)   2NO == N2O2     (fast)                                                

2)   N2O2 + H2 à H2O + N2O    (slow)                           

3)   N2O + H2 à N2 + H2O     (fast)

Show that the mechanism is consistent with the rate law.                                                           

                                                        

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