## Calculating Gibbs Free Energy [ENDORSED]

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

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

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

Kyra Dingle 1B
Posts: 55
Joined: Fri Sep 29, 2017 7:04 am

### Calculating Gibbs Free Energy

When asked to calculate Gibbs Free Energy when should you use the equation deltaH - T*deltaS compared to using the standard formation values and subtract the sum of the products from the sum of the reactants?

Sabrina Dunbar 1I
Posts: 57
Joined: Fri Sep 29, 2017 7:07 am
Been upvoted: 1 time

### Re: Calculating Gibbs Free Energy

You will be able to tell which one you can use by the values you are given. If you have the ∆Formation for the reactants and the products given, then use that method for solving for ∆G. Ig you are given the proper values to calculate ∆G using enthalpy and entropy, then that method would be the best to use. So pretty much just look at the given values and go from there!

Tiffany 1B
Posts: 32
Joined: Fri Sep 29, 2017 7:05 am

### Re: Calculating Gibbs Free Energy  [ENDORSED]

Hi,
So I think the first one is used for any constant temperature while the standard Gibbs free energy is used when both the products and reactants are in their standard states at one bar and the temp(which I think is) 298K. Other than that I'd say just using what you're given is main way to tell. Hope that helps.