## gas constant for gibbs free energy

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

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

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

bellaha4F
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### gas constant for gibbs free energy

when using the gas constant for the gibbs free energy equation (delta G= -RTlnK), do you always use 8.314 J/mol.K?

Selena Yu 1H
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### Re: gas constant for gibbs free energy

Yes, because the units for Gibbs free energy is J/mol or kJ/mol and you cancel out the K with temperature.

Jaci Glassick 2G
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### Re: gas constant for gibbs free energy

Whenever using the gas constant, you are always trying to match up the units. In the case of G=RTlnK you are always going to use 8.314 J/mol.K because the units match (G is in J/mol, T is in kelvin).

Hailey Kim 4G
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### Re: gas constant for gibbs free energy

Gibbs free energy is in J/mol and temperature is in Kelvins. Therefore, you would use 8.314 J/mol.K in order to cancel out all the units and find a value for K (which does not have any units).

Katie Kyan 2K
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### Re: gas constant for gibbs free energy

Yes you would use 8.314 J/mol*K because the units for Gibbs Free Energy involves J/mol or kJ/mol. Thus, when using the equation delta G= -RTlnK you would use 8.314 J/mol*K as the value of the Gas constant.

Gurmukhi Bevli 4G
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Joined: Wed Nov 14, 2018 12:20 am

### Re: gas constant for gibbs free energy

Yes, since that R-value is in J/Kmol (or kJ/Kmol), which can be cancelled out to give you an appropriate value (in units) for G (J/mol).