Angelica J.

asked • 10/14/15

Enthalpy of reaction problem? Please help?

Can you please help me?? I am so lost on how to solve this, and would love to see exactly how to do it. I know you have to break up the compounds into ions if they are aq, but not much else. In addition, I don't have a Hf value for NO3, so is that something you look up or have to memorize? Anyways, here is the question:
 
 
Using the values for ?Hf, determine the ?H(enthalpy) for the following reaction: Na2CO3 (aq) + Mg(NO3)2 (aq) → 2 NaNO3 (aq) + MgCO3 (s)
 
Substance (state)          Hf (kJ/mol)
Na+ (aq)                      -240.1
Cl- (aq)                         -167.2
 
 
MgCO3 (s)                     -1096
Mg+2 (aq)                     -466.9
CO3 2- (aq)                   -677.1
 
 
Thank you so much! I really want to learn what to do! 

1 Expert Answer

By:

Christopher J. answered • 10/15/15

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Angelica J.

Thank you so much Mr. Christopher. While I was waiting for a person to answer this, I tried working on it and also got 48. I am very happy that I know I did it correctly. Thank you for the tip about the NO3- ions as well. I did not think about how those are spectator ions, so it will be much easier to solve problems like this in the future. :) Have a great afternoon!
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10/15/15

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