## Differences in (delta)G^o equations

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

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

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

Shanzey
Posts: 120
Joined: Wed Sep 18, 2019 12:20 am

### Differences in (delta)G^o equations

How do we know when to use the lnQ equation or the lnK equation? Is it dependent on whether the system is in equilibrium or not?

PranaviKolla2B
Posts: 114
Joined: Fri Aug 30, 2019 12:17 am

### Re: Differences in (delta)G^o equations

K means that the system is in equilibrium and Q means that it is not.

Andrew Pfeiffer 2E
Posts: 101
Joined: Sat Sep 28, 2019 12:16 am

### Re: Differences in (delta)G^o equations

As with equilibrium calculations, K is for when the reaction is at equilibrium, and Q (reaction quotient) is for non-equilibrium reactions.

Lauren Stack 1C
Posts: 100
Joined: Sat Aug 17, 2019 12:18 am

### Re: Differences in (delta)G^o equations

lnQ is used when the system is not at equilibrium, while lnK is found at equilibrium. If you think about it, Q = K at equilibrium, so you can see the connection.