## Using Q

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

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

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

Ardo 2K
Posts: 31
Joined: Fri Sep 29, 2017 7:05 am

### Using Q

Can we use Q when calculating Gibbs free energy with the Equation deltaG= -RTlnQ? Or does the reaction need to be at equilibrium for us to use this equation, in which case we would use K.

Curtis Wong 2D
Posts: 62
Joined: Sat Jul 22, 2017 3:00 am

### Re: Using Q

If the reaction is not at equilibrium, then we can use Q and that equation to solve for Gibbs Free Energy. If the reaction comes to equilibrium, then we use K.

Danah Albaaj 1I
Posts: 50
Joined: Fri Sep 29, 2017 7:07 am

### Re: Using Q

Using Q is for when the reaction is not at equilibrium. So then you would use both the result from when the reaction at equilibrium found from ∆G˚= -RTlnK and the value of RTlnQ. Professor Lavelle went over the equation at the end of lecture on Friday before the Van't Hoff equation if you would like to see how it is derived.