## 9.57 hmwrk 6th edition

$\Delta G^{\circ}= \Delta H^{\circ} - T \Delta S^{\circ}$

$\Delta G^{\circ}= -RT\ln K$

$\Delta G^{\circ}= \sum \Delta G_{f}^{\circ}(products) - \sum \Delta G_{f}^{\circ}(reactants)$

Lina Petrossian 1D
Posts: 77
Joined: Fri Oct 05, 2018 12:16 am

### 9.57 hmwrk 6th edition

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?

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

### Re: 9.57 hmwrk 6th edition

*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

Lina Petrossian 1D
Posts: 77
Joined: Fri Oct 05, 2018 12:16 am

### Re: 9.57 hmwrk 6th edition

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?