## 15.37 C [ENDORSED]

$\frac{d[R]}{dt}=-k[R]; \ln [R]=-kt + \ln [R]_{0}; t_{\frac{1}{2}}=\frac{0.693}{k}$

sofiakavanaugh
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Joined: Thu Jul 13, 2017 3:00 am
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### 15.37 C

14.0 g of SO2Cl2 in 2500. L vessel is heated to a specific temp, what mass will remain after 1.5 hours for a first order reaction and for a k value of 2.81 x10^-3 1/min

I keep doing this problem over and over again, and for some reason I am ending up with more grams than the initial, which is obviously wrong. I redid the calculations and everything and can't figure out what I am doing wrong, I even had my tutor look at it and she couldn't figure it out either.

I converted the time to 90 min, the 14 grams to moles and then divided by the volume to get the concentration (0.000041492 M), and then plugged these into ln[A]t=-kt+ln[A]o. After plugging in the numbers I made everything on the right hand side e^values, to cancel out the ln on the left, and then for some reason keep getting the wrong answer. I would really appreciate help on this problem.

Thanks!

Hannah Chew 2A
Posts: 76
Joined: Fri Sep 29, 2017 7:05 am
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### Re: 15.37 C  [ENDORSED]

Hi! The steps you wrote are exactly what I did, but it's hard to tell where you went wrong without listing the exact numbers. Maybe you can figure out which numbers differ from mine?

Here are the #'s I got:
[A] initial = 4.15x10^-5 mol/L
[A] = e ^ -10.3 = 3.22 x 10^-5 mol/L
grams of [A] = 10.9g