What is the concentration?

Question

The reaction X products is second order in X  and has a rate constant of 0.035 M^-1s^-1.

If a reaction mixture is initially 0.50 M in X, what is the concentration of X after 140. seconds?

Answer 1

Let's look at the integrated rate law for a 2nd order reaction. It is...

1/[X] = 1/[X]_o + kt

Substituting our known values and solving for [X], we have...

1/[X] = 1/0.50 M + (0.035 M^-1s^-1)(140 s)

1/[X] = 2 + 4.9 = 6.9

[X] = 0.14 M