The reaction A → B + C is known to be zero order in A with a rate constant of 3.8 * 10-2 mol/L • s at 25° C. An experiment was run at 25°C where [A]0 = 1.0 * 10-3 M. What is the rate after 6.5 minutes? Group of answer choices

The rate is 0.038 M/s

Explanation:

The reaction follows a zero order

Let the concentration of A after 6.5 minutes be y

Rate = k[y]^0 = change in concentration/time

k (rate constant) = 3.8*10^-2 mol/L. s

Initial concentration of A = 1*10^-3 M

Change in concentration = 1*10^-3 - y

Time = 6.5 minutes = 6.5*60 = 390 seconds

3.8*10^-2*1 = 1*10^-3 - y/390

0.001 - y = 0.038*390

0.001 - y = 14.82

y = 0.001 - 14.82 = - 14.819 M

Rate = change in concentration/time = [0.001 - (-14.819) ]/390 = (0.001+14.819) / 390 = 14.82/390 = 0.038 M/s