Question

The following reaction is second order in [A] and the rate constant is 0.033 M−1s−1:

A → B
The concentration of A was 0.29 M at 28 s. What was the initial concentration of A?
A. 0.29 M
B. 0.58 M
C. 0.87 M
D. 1.16 M

Answer 1

To determine the initial concentration of A in a second-order reaction, rearrange the rate equation and solve for the unknown concentration. In this case, the initial concentration of A is 0.58 M.

Step-by-step explanation:

To determine the initial concentration of A, we can use the rate equation for a second-order reaction, which is rate = k[A]2. Given that the rate constant (k) is 0.033 M-1s-1 and the concentration of A at 28 s is 0.29 M, we can rearrange the rate equation to solve for the initial concentration of A. Plugging in the known values, we have:

rate = k[A]2

0.033 M-1s-1 = (0.29 M - x)2

Solving for x, we find that the initial concentration of A is 0.58 M.