## 15.39

$\frac{d[R]}{dt}=-k[R]^{2}; \frac{1}{[R]}=kt + \frac{1}{[R]_{0}}; t_{\frac{1}{2}}=\frac{1}{k[R]_{0}}$

Belle Calforda3f
Posts: 67
Joined: Fri Sep 29, 2017 7:07 am

### 15.39

for 15.39 b, why does the solutions manual have ".37[a] initial as part of the solution. Where is the .37 coming from?

sofiakavanaugh
Posts: 58
Joined: Thu Jul 13, 2017 3:00 am
Been upvoted: 1 time

### Re: 15.39

Hi friend!

So the 0.37 is actually for part a, it just is lined up weirdly in the solutions manual so it looks like its part of part b.

Hope this helps

Katie Blann 1E
Posts: 29
Joined: Tue Nov 15, 2016 3:00 am

### Re: 15.39

Hi, that is actually for part b and 0.37[A]initial comes from finding the moles total moles of A with the information give about concentration B.
Because A--> 2B + C so, [A]total= [A]initial-([B]x([A]/2[B])) to give you 0.055(mol A)/L which is equivalent to 0.37[A]initial