## given values

$\ln K = -\frac{\Delta H^{\circ}}{RT} + \frac{\Delta S^{\circ}}{R}$

Sarah Blake-2I
Posts: 153
Joined: Fri Aug 30, 2019 12:16 am

### given values

Would we be given delta S naught and delta G naught or would we need to solve for these values in a problem and how is that calculation different than just calculating delta G or delta S? Thank you!

Frank He 4G
Posts: 50
Joined: Tue Nov 12, 2019 12:19 am

### Re: given values

I don't know if we will encounter problems where we have to calculate the delta G naught or delta H naught in order to then use the Van't Hoff equation, but usually what we do with this equation is calculate K for a reaction at a different temperature when we know the delta H naught of a reaction, using the second form of the equation that we derived in class: lnK2/K1 = -delta H naught/R * (1/T2 - 1/T1)

As you can see, if we use that equation, we do not have to know or solve for S.

Wilson 2E
Posts: 100
Joined: Sat Aug 17, 2019 12:18 am

### Re: given values

If we did have to solve for delta H naught, I assume you could do so either through the standard enthalpies of formation or even the deltaU = q + w formula.

Matt F
Posts: 100
Joined: Sat Aug 17, 2019 12:17 am

### Re: given values

I think it could be reasonable to have to solve for delta H naught or even one of the temperatures depending on the wording of the problem. The main use for the equation though is calculating K at different temperature values given a value for delta H naught, so ideally you would just be focusing on K and its dependence on temperature rather than solving for various parts of the equation