Question

Enter your answer in the provided box. The reaction 2A → B is first order in A with a rate constant of 2.8 × 10−2 s−1 at 80°C. How long (in seconds) will it take for A to decrease from 0.900 M to 0.130 M?

Answer 1

For the reaction:

2A    B ; being the order of reaction with respect to A equal to one (1)

The kinetic expression is given by:

Separating the previous equation into variables and integrating in the following interval,

You have:

Clearing time t from the previous expression we have:

Substituting the value of k= 2.8x10^-2 s^-1and the values of the concentrations for t = 0 and t indicated above, we have:

Then, it is concluded that the time it takes A to reduce from 0.900 M to 0.130 M is: