## Gibbs Free Energy Equation that relates K

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

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

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

BNgo_2L
Posts: 95
Joined: Wed Sep 11, 2019 12:17 am

### Gibbs Free Energy Equation that relates K

For the equation, delta G = delta G (naught) + RTlnQ, what'sthe difference between delta G and delta G (naught)?

Kevin Xu 4F
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Joined: Fri Aug 09, 2019 12:16 am

### Re: Gibbs Free Energy Equation that relates K

Delta G not is the change in gibbs free energy given conditions under standard pressure (1 atm) and with stoichiometric coefficients corresponding to the balanced chemical reaction. Hence, the equation to calculated it is delta G not = -R * T * ln K. The K here represents concentrations at equilibrium ratios. Delta G represents the change in gibbs free energy of reaction not under stoichiometric ratios at equilibrium. Hence, delta G equals delta G not + R * T * ln Q. The Q represents concentrations not at equilibrium ratios.

Sebastian Lee 1L
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### Re: Gibbs Free Energy Equation that relates K

$\Delta G^{\circ}$ refers to the Gibbs free energy of a reaction at the STANDARD state whereas $\Delta G$ refers to the Gibbs free energy under other non-standard conditions. For example, you might want to find $\Delta G$ when the reaction is occurring at a different temperature T or when it's not at equilibrium (find Q).

Miriam Villarreal 1J
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Joined: Sat Aug 17, 2019 12:16 am

### Re: Gibbs Free Energy Equation that relates K

∆G is the change of Gibbs (free) energy for a system and ∆G° is the Gibbs energy change for a system under standard conditions (1 atm, 298K). ... Where ∆G is the difference in the energy between reactants and products. In addition ∆G is unaffected by external factors that change the kinetics of the reaction

Dan M -3E
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Joined: Wed Sep 18, 2019 12:19 am

### Re: Gibbs Free Energy Equation that relates K

This equation takes into account the deltaG(naught) and adds/subtracts what would be different because of the conditions not being standard.