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9.57 hmwrk 6th edition

Posted: Tue Feb 19, 2019 7:27 pm
by Lina Petrossian 1D
9.57 Calculate the standard reaction entropy, enthalpy, and Gibbs free energy for each of the following reactions from data in Appendix 2A:
(a) the decomposition of hydrogen peroxide:
2 H2O2(l) -> 2 H2O(l) + O2(g)

For part a, I keep getting delta H = -98.05 kj per mole, but thats not what it says in the answer key. Can someone go through the steps to solve pls?

Re: 9.57 hmwrk 6th edition

Posted: Tue Feb 19, 2019 7:51 pm
by Madeline Ho 1C
*make sure you're using the correct deltaH values: H2O and H2O2 liquid
deltaH = deltaHf(H2O) + deltaHf(O2) - deltaHf(H2O2) = 2(-285.83kJ/mol) + 0 - 2(-187.78 kJ/mol) = -196.10 kJ/mol

Re: 9.57 hmwrk 6th edition

Posted: Tue Feb 19, 2019 8:04 pm
by Lina Petrossian 1D
So if the answer is -196.10 kj/mol. What is per mol referring to? Per mole of what? Why is the answer not half that value like i originally got?