### HW 15.23

Posted:

**Mon Mar 05, 2018 9:21 pm**For 15.23c, why is 'ln' not included in the equation? Since the equation that we start with is ln([A]t-[A]0)=-kt, I thought the equation we end up with should be ln[A]t=whatever?

Created by Dr. Laurence Lavelle

https://lavelle.chem.ucla.edu/forum/

https://lavelle.chem.ucla.edu/forum/viewtopic.php?f=144&t=29020

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Posted: **Mon Mar 05, 2018 9:21 pm**

For 15.23c, why is 'ln' not included in the equation? Since the equation that we start with is ln([A]t-[A]0)=-kt, I thought the equation we end up with should be ln[A]t=whatever?

Posted: **Mon Mar 05, 2018 10:02 pm**

You do end up using the natural log (ln) in this calculation, after you solve for the [A]_{t}! After you get that value, you plug it in

k = (ln([A]_{0}/[A]_{t})) / t to get k.

k = (ln([A]

Posted: **Mon Mar 05, 2018 10:02 pm**

In the solutions manual, they were first trying to determine what the concentration of [A]t was before using the first order rate law equation.