Question

Nitrogen pentoxide decomposes according to equation:

2N₂O₅(g) →4NO₂(g) +O₂(g).

This first order reaction was allowed to proceed at 40°C and the data below were collected:

[N2O5] (M)	Time (min)
0.400	0.00
0.289	20.0
0.209	40.0
0.151	60.0
0.109	80.0

(a) Calculate the rate constant. Include units with your answer.

(b) What will be the concentration of N₂O₅ after 100 minutes?

(c) Calculate the initial rate of reaction.

Answer 1

(a) When t = 20 min, [A] = 0.289 mol L^–1

Also, [A]0 = 0.400 mol L^–1

For a first order reaction