Question

The rate constant for this first‑order reaction is 0.550 s−10.550 s−1 at 400 ∘C.400 ∘C. A⟶products A⟶products How long, in seconds, would it take for the concentration of AA to decrease from 0.690 M0.690 M to 0.220 M?

Answer 1

Answer:

$t=2.08s$

Explanation:

Hello,

In this case, for first order reactions, we can use the following integrated rate law:

$ln(\frac{[A]}{[A]_0} )=kt$

Thus, we compute the time as shown below:

$t=-\frac{ln(\frac{[A]}{[A]_0} )}{k}=- \frac{ln(\frac{0.220M}{0.690M} )}{0.55s^{-1}} \\\\t=-\frac{-1.14}{0.550s^{-1}}\\ \\t=2.08s$

Best regards.