The rate constant for this second‑order reaction is 0.190 M - 1 ⋅ s - 1 0.190 M-1⋅s-1 at 300 ∘ C. 300 ∘C. A ⟶ products A⟶products How long, in seconds, would it take for the concentration of A A to decrease from 0.820 M 0.820 M to 0.340 M?

9.1 seconds

Explanation:

Given that for a second order reaction

1/[A]t = kt + 1/[A]o

Where [A]t = concentration at time = t = 0.340M

[A]o = initial concentration = 0.820M

k = rate constant for the reaction=0.190m-1s-1

t = time taken for the reaction (the unknown)

Hence;

(0.340) ^-1 = 0.190*t + (0.820) ^-1

t = (0.340) ^-1 - (0.820) ^-1/0.190

t = 9.1 seconds

Hence the time taken for the concentration to decrease from 0.840M to 0.340M is 9.1 seconds.