Question

12. The rate law for the reaction 2NO2 + O3 → N2O5 + O2 is rate = k[NO2][O3]. Which one of the following mechanisms is consistent with this rate law?

A) NO2 + NO2 → N2O4                (fast)

N2O4 + O3 → N2O5 + O2     (slow)

B) NO2 + O3 → NO5                           (fast)

NO5 + NO5 → N2O5 + 5/2O2     (slow)

C) NO2 + O3 → NO3 + O2     (slow)

NO3 + NO2 → N2O5           (fast)

D) NO2 + NO2 → N2O2 + O2     (slow)

N2O2 + O3 → N2O5                   (fast)

13. Concerning the rate law, Rate = k[A][B][C], what are appropriate units for the rate constant k?

A) s-1    

B) M-1s-1    

C) M-2s-1    

D) M/s   

E) M2/s

II. (15 points, 3 point each) Show your work in detail (step by step). You must show your work to get the full credit. Just circling answer will not get any point.

1. A reaction is experimentally found to follow the rate law, Rate = k[A]2 where k = 0.330 M-1min-1. Starting with [A]o = 7.50 M, how many seconds will it take for [A]t = 5.25 M

2. The following mechanism has been suggested for the reaction:

         H2O2 + 2H+ + 2I – → I2 + 2H2O

H2O2 + I – → HOI + OH –	Slow
OH – + H+ → H2O	Fast
HOI + H+ + I – → I2 + H2O	Fast

Identify all intermediates included in this mechanism.

3. For the reaction C6H14(g) → C6H6(g) + 4H2(g), ΔP(H2)/Δt was found to be 2.5 × 10–2 atm/s, where ΔP(H2) is the change in pressure of hydrogen. Determine ΔP(C6H14)/Δt for this reaction at the same time.

A) 2.5 × 10–2 atm/s D) 0.10 atm/s

B) –6.2 × 10–3 atm/s E) 6.2 × 10–3 atm/s

C) –2.5 × 10–2 atm/s

Answer 1