Please help with this problems I'm having major trouble with it and show work. Appreciate it! there are 2 parts to the question

Question

Question

Three experiments that have identical conditions were performed to measure the initial rate of decomposition of ammonia on a platinum surface: 2NH₃(g)--> N₂(g) + 3H₂(g). The results for the three experiments in which only the NH₃ concentration was varied are as follows in the table:

 

Experiment |  (NH₃) (M)  |   Rate (M/s) 

       1        |      0.040     |       4.5x10^-2

       2        |      0.080     |       9.0x10^-2

       3        |      0.120     |       1.35x10^-1

 

A.) Write the rate law for the reaction.

B.) Find the value and units of the specific rate constant (K) show your work. 

Answer 1

Doubling the NH3 concentration doubles the rate, so the rate is given by rate = k[NH3].  The k value is 4.5 x 10^-2 / .040 = 1.125 s^-1.  So, rate = 1.125 s^-1 [NH₃].