## Calculating Gibbs Free Energy Equations

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

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

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

annabel 2A
Posts: 67
Joined: Fri Sep 28, 2018 12:18 am

### Calculating Gibbs Free Energy Equations

For 6th Edition Chapter 9 #55: Write a balanced chemical equation for the formation reaction of (a) NH3 (g); (b) H2O(g); (c)CO(g); (d) NO2(g). For each reaction, determine H,S, and G from data in Appendix 2A.

When calculating the Grxn, can we use the equation "deltaG = deltaGformation(products) - deltaGformation(reactants)"?
The solutions manual uses the equation "deltaG = deltaH - TdeltaS" and the answer is 0.05 kJ/mol off from what I got when I used the other equation.

Kessandra Ng 1K
Posts: 67
Joined: Fri Sep 28, 2018 12:25 am

### Re: Calculating Gibbs Free Energy Equations

I think you can use both, and they should give similar (but not necessarily the same) answers. Since you've already found ∆H and ∆S, then it would make sense to use the ∆G = ∆H - T∆S equation.

Cole Elsner 2J
Posts: 88
Joined: Fri Sep 28, 2018 12:25 am

### Re: Calculating Gibbs Free Energy Equations

Both of these methods work! In the end it's all a state function so your path is up to you. With these problems just try to make the most out of what's GIVEN to you.