Fundamentals E  [ENDORSED]

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Berivan Kamran 3E
Posts: 13
Joined: Wed Nov 18, 2015 3:00 am

Fundamentals E

Postby Berivan Kamran 3E » Thu Jun 23, 2016 9:17 pm

E.23 How many moles of H2O in 2.00g of NA2CO3 x 10H2O

First thing I did was add all of the masses up, and I came to 286g.
2.00g divided by 286 g, I got .007 moles. The text book says .069 moles. Where did I go wrong? Please help.

Rika Jitosho 2E
Posts: 29
Joined: Fri Jun 17, 2016 11:28 am

Re: Fundamentals E  [ENDORSED]

Postby Rika Jitosho 2E » Fri Jun 24, 2016 1:20 pm

Looking at how I solved this question, I believe that when you divided 2.00g by the molar mass 286.21 g.mol-1, that was correct. But after that, I still multiplied that fraction by 10mol H20 over 1mol Na2CO3 . 10H2O. I put moles of H2O as my numerator in the second fraction because moles of H2O was what I was solving for. That way, when you multiply what you got from your initial answer (0.00699) by 10/1, or just 10, I believe you should be getting about 0.0699mol H2O as the final answer.


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