Determining reaction order : Rate Laws(Chemistry)
The reaction of nitric oxide with hydrogen at 1280C is as follows:
2NO(g) +2H2 (g) -> N2(g) + 2H2O(g)
From the following experimental data, determine the rate law and the rate constant.
30 POINTS!

The order of the reaction is 4.

The rate law of the reaction will be :

Rate constant of the reaction: k =

Explanation:

Let the stoichiometric coefficient of the NO and in rate law be x and y .

Rate of the reaction is given  by :

1) When ,

R =  0.00600 M/s

..[1]

2) When ,

R =  0.144 M/s

..[2]

3) When ,

R =  0.0120 M/s

..[3]

Dividing [1] and [3]

y = 1

Dividing [1] and [2]

x = 3

The order of the reaction = x + y = 3 + 1 = 4

The rate law of the reaction will be :

Rate constant of the reaction: k

When ,

R =  0.00600 M/s

..[1]

n2(g) + 3h2-> 2nh3(g)   this is the balanced equation

note the mole ratio between n2, h2 and nh3.   it is 1 : 3 : 2   this will be important.

moles n2 present = 28.0 g n2 x 1 mole n2/28 g = 1 mole n2 present

moles h2 present = 25.0 g h2 x 1 mole h2/2 g = 12.5 moles h2 present

based on mole ratio, n2 is limiting in this situation because there is more than enough h2 but not enough n2.

moles nh3 that can be produced = 1 mole n2 x 2 moles nh3/mole n2 = 2 moles nh3 can be produced

grams of nh3 that can be produced = 2 moles nh3 x 17 g/mole = 34 grams of nh3 can be produced

note:   the key to this problem is recognizing that n2 is limiting, and therefore limits how much nh3 can be produced.

the correct answer would be d. hope this !