## Delta G vs Delta G0

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

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

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

Pratyush Kandimalla 2O
Posts: 33
Joined: Wed Sep 21, 2016 3:00 pm
Been upvoted: 2 times

### Delta G vs Delta G0

When asked for delta G, being given Delta H0 and Delta S0, should we just plug in the given temperature (Delta G0 = DeltaH0 - T DeltaS0) or
calculate Delta G using -

Delta G = DeltaG0 + RT ln(Q) <Where DeltaG0 = DeltaH0 - (298)DeltaS0>

????

Nilla Sivakumar 2H
Posts: 22
Joined: Wed Sep 21, 2016 2:58 pm

### Re: Delta G vs Delta G0

I think you just plug it into the first one because you have the 0 subscript on all the givens, so you'd be solving for delta G0.

Rachel Wile 2D
Posts: 49
Joined: Sat Jul 09, 2016 3:00 am

### Re: Delta G vs Delta G0

You would just solve using the first equation. To solve the second equation, you would need the reaction quotient Q.

Randon_Zahlout_3B
Posts: 16
Joined: Wed Sep 21, 2016 2:57 pm

### Re: Delta G vs Delta G0

But what is the actual difference between calculating a $\Delta G versus a \Delta G^{\circ}$ ?

EmilyLeibovitch2E
Posts: 29
Joined: Wed Nov 18, 2015 3:00 am

### Re: Delta G vs Delta G0

You use the same equations for both. The difference is that deltaG0 is with standard conditions whereas deltaG is with nonstandard conditions.

Catherine_Zhang_1H
Posts: 23
Joined: Fri Jul 22, 2016 3:00 am

### Re: Delta G vs Delta G0

The naught sign means that the substance is in standard state so delta g naught would be calculated using standard enthalpy of formation and standard entropy values. You can find the standard enthalpy of formation of the reaction by doing sum of the standard enthalpy of formation of products - reactants (values usually given in a chart). And you can do the same with the standard entropy values then plug the values into the equation delta G0= deltaH0 -TdeltaS0. Another method would be using deltaG0= -RTlnK whereas delta G= delta G0 + RTlnQ