### 15.35

Posted:

**Mon Mar 05, 2018 12:14 am**Not sure why I'm not getting the right answer

The half-life for the second-order reaction of a substance A is 50.5 s when [A]0 = 0.84 mol*L^-1. Calculate the time needed for the concentration of A to decrease to (a) one-sixteenth....of its original value

I used the the half life 2nd order reaction to get k:

t(1/2)=1/k*[A]0

50.5=1/k*0.84

k=0.0236

ln(1/16)=-0.0236(t)

t=118s

but the answer is 7.4 x 10^2 s.

If someone can tell me what I'm doing wrong, I would greatly appreciate it.

The half-life for the second-order reaction of a substance A is 50.5 s when [A]0 = 0.84 mol*L^-1. Calculate the time needed for the concentration of A to decrease to (a) one-sixteenth....of its original value

I used the the half life 2nd order reaction to get k:

t(1/2)=1/k*[A]0

50.5=1/k*0.84

k=0.0236

ln(1/16)=-0.0236(t)

t=118s

but the answer is 7.4 x 10^2 s.

If someone can tell me what I'm doing wrong, I would greatly appreciate it.