For the following gaseous reaction:

Question

2 NO₂ +F₂ --> 2NO₂F

Generalized rate equation = k(PNO₂)² (PF₂)

You test the initial kinetics of the above reaction and get the following results:

Initial: P_NO2 = 1 atm, P_F2 = 1 atm --> rate of P_NO2F formation = 0.1 atm/sec

Initial: P_NO2 = 0.5 atm, P_F2 = 1 atm --> rate of P_NO2F formation = 0.05 atm/sec

Initial: P_NO2 = 1 atm, P_F2 = 0.25 atm --> rate of P_NO2F formation = 0.025 atm/sec

Rewrite the generalized rate equation, now filled in with variables to describe the orders of the reactants

Answer 1

From the first 2 tests, you can see that it is 1st order with respect to P_NO2. You can tell this because when you halve the pressure of NO₂, you also halve the rate.

From the first and third tests, you can see that it is also 1st order with respect to P_F2. Again, because when you reduce the pressure of F₂ by 1/4, you also reduce the rate by 1/4.

The rate equation is

rate = k(NO₂)(F₂) where parentheses ( ) indicate pressure