## Calculating Gibbs Free Energy

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

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

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

LNgo 1G
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### Calculating Gibbs Free Energy

When calculating Gibbs free energy, do you take into account stoichiometric coefficients?

LBacker_2E
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### Re: Calculating Gibbs Free Energy

deltaG= -nFE: You only take into account the moles of electrons (the stoichiometric coefficient in front of the electron), because the coefficients in front of the compounds do not affect Ecell.

Nick Fiorentino 1E
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### Re: Calculating Gibbs Free Energy

G=H-TS

Enthalpy (H) and entropy (S) take into account stoichiometric coefficients, so I guess you could say that G requires you take into account stoichiometric coefficients. However, when calculating G in regards to electrochemistry, you do not take them into account.

005384106
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### Re: Calculating Gibbs Free Energy

In what situation would S(total) ever be = 0?

AniP_2D
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### Re: Calculating Gibbs Free Energy

When calculating deltaG using the products minus reactants method, you would have to take into account the stoichiometric coefficients.

WGaines_2E
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### Re: Calculating Gibbs Free Energy

005384106 wrote:In what situation would S(total) ever be = 0?

S can only be 0 for a molecule at 0K which is theoretically unacheivable. If is is 0 between reactants and products in a reaction, that is because they had the same entropy value with opposite signs (coincidence)

005384106
Posts: 101
Joined: Sat Aug 24, 2019 12:16 am

### Re: Calculating Gibbs Free Energy

WGaines_2E wrote:
005384106 wrote:In what situation would S(total) ever be = 0?

S can only be 0 for a molecule at 0K which is theoretically unacheivable. If is is 0 between reactants and products in a reaction, that is because they had the same entropy value with opposite signs (coincidence)

I just wanted to clarify to make sure I understood this, can reactants and products have different entropy values?