chemistry question

Question

The rate constant for the reaction is 0.750 M−1⋅s−1  at 200 ∘C.

A⟶products

If the initial concentration of A is 0.00320 M, what will be the concentration after 665 s?

Please help...

Answer 1

Because the units of the rate constant are M^-1s^-1, this tells us that the reaction is SECOND ORDER.

Once we know that, we can choose the appropriate equations to use. For a second order reaction, the integrated rate law is 1/[A] = 1/[A]_o + kt

[A] = ?

[A]_o = 0.00320 M

k = 0.750 M-1s-1

t = 665 s

So we have all we need to solve for [A]...

1/[A] = 1/0.00320 + (0. 750)(665)

1/[A] = 312.5 + 498.8 = 811

[A] = 0.00123 M