Question

Consider the first-order reaction J rightwards arrow K. In a kinetics experiment, the starting concentration of J was 0.0250 M and the concentration after 14.5 seconds was found to be 0.0130 M. What is the value of the rate constant, k?

Answer 1

The rate constant, k, for the first-order reaction can be determined using the integrated rate law. With the initial and final concentrations provided, and the time elapsed, the calculation yields k approximately equal to 0.0916 s^-1.

Step-by-step explanation:

To calculate the rate constant, k, for the first-order reaction J to K, we can use the integrated rate law for a first-order reaction, which is ln([A]/[A]0) = -kt. Here, [A]0 is the initial concentration of J, and [A] is the concentration of J after time t.

Given:
[A]0 = 0.0250 M (initial concentration of J),
[A] = 0.0130 M (concentration of J after 14.5 seconds),
t = 14.5 seconds.

Plugging these values into the equation, we get:
ln(0.0130 M / 0.0250 M) = -k(14.5 seconds)

k = -ln(0.0130/0.0250) / 14.5
k ≈ 0.0916 s-1