Question

Consider the reaction: 2N2O(g) ---> 2N2(g) + O2(g)

A. Express the rate of reaction in terms of the change in concentration of each of the reactants and products.

B. In the first 15.0s of the reaction, 0.015mol of O2 is produced in a reaction vessel with a volume of 0.500L. What is the average rate of the reaction during this time interval?

C. Predict the rate of change in the concentration of N2O during this time interval. In other words, what is ∆[N2O]/∆t?

Answer 1

Given reaction :

2 N2O (g) -- > 2 N2 (g) + O2 (g)

A. Here we have to express rate of the reaction with respect to each reactant and product species.

Rate = -1/2 Delta [N2O]/dt = +1/2 Delta [N2]/delta t = delta [O2]/dt

Here we used minus sign to show expression of rate for reactants, the purpose is to show the reactant’s concentration is decreasing.

And shown positive sign to the product since their concentration increases.

B)

Average rate with respect to O2 = Delta [O2]/ delta t

Lets calculate the concentration of O2

[O2] = mol of O2 / volume of tank in L

= 0.015 mol O2 / 0.500 L

=0.03 M

Calculation of delta t :

Here we are given the time elapsed during the formation of 0.015 mol O2

Therefore , delta t = 15.0 s

Average rate with respect to O2 = 0.03M/15.0s = 0.002

C.

We relate rate of formation of O2 with rate of decomposition of N2O

Rate = -1/2 Delta [N2O]/dt = delta [O2]/dt

-1/2 Delta [N2O]/dt = 0.002

Delta [N2O]/dt = - 0.002 * 2 = -0.004