## Question 8.57 (Sixth Edition)

Steve Magana 2I
Posts: 61
Joined: Fri Sep 28, 2018 12:24 am

### Question 8.57 (Sixth Edition)

Question: Determine the reaction enthalpy for the hydrogenation of ethyne to ethane, C2H2(g) + 2 H2(g) --> C2H6(g), from the following data: deltaHc(C2H2, g) = -1300. kJ/mol, deltaHc(C2H6, g) = -1560. kJ/mol, deltaHc(H2, g) = -286 kJ/mol.

I was able to do this problem, but my answer does not match the solutions manual. Can someone help me with this to see where I went wrong please? Thank you!

Posts: 37
Joined: Mon Apr 23, 2018 3:00 am

### Re: Question 8.57 (Sixth Edition)

I'm having trouble with this too... I did the sum of the standard enthalpy of combustion for products - reactants but I got +312 kJ instead of -312 kJ. I know it should be negative because it's a combustion reaction, thus exothermic, but that math doesn't match up.

Alexa_Henrie_1I
Posts: 61
Joined: Fri Sep 29, 2017 7:03 am

### Re: Question 8.57 (Sixth Edition)

Posts: 37
Joined: Mon Apr 23, 2018 3:00 am

### Re: Question 8.57 (Sixth Edition)

viewtopic.php?t=17644
I found this thread that explains how to do the problem well. Essentially, you have to find the combustion reaction for each element of the given reaction and then use method 1 for solving for enthalpy to find the reaction enthalpy for the hydrogenation of ethyne to ethane.

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