## 5G.13 and 5G.19

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

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

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

Savannah Mance 4G
Posts: 107
Joined: Fri Aug 30, 2019 12:17 am

### 5G.13 and 5G.19

What is the difference between the two questions because they both ask for the Gibbs free energy of the rxn I2<-->2I but they have different answers. Can someone explain why they're different?

Ruby Tang 2J
Posts: 102
Joined: Fri Aug 30, 2019 12:15 am

### Re: 5G.13 and 5G.19

While 5G.19 is asking for the standard Gibbs free energy, 5G.13 is asking for the reaction Gibbs free energy. The difference is that if you consider the equation ΔG = ΔGnaught + RTlnQ, we know that depending on the concentration of the products and reactants, ΔG (the reaction Gibbs free energy) can deviate from ΔGnaught (the standard Gibbs free energy). This is the reason why 5G.19 and 5G.13 have different values as their answers.