## concept help

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

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

### concept help

What is the purpose and meaning of the Van't Hoff equation? And when would we use it instead of the normal Gibbs Free Energy equation?

905373636
Posts: 62
Joined: Thu Aug 01, 2019 12:15 am

### Re: concept help

Van't Hoff relates a reaction's equilibrium constant Keq with temperature, standard enthalpy, and standard entropy -- so it'd be useful in modeling how the equilibrium constant changes due to T, S, and H changes I assume in a more definite way.

[url]https://en.wikipedia.org/wiki/Van_%27t_Hoff_equation#/media/File:Endothermic_Reaction_van't_Hoff_Plot.png/[url]

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

### Re: concept help

We also derived in class a form of the equation that lets us calculate the K of a reaction when we only know the delta H naught, which goes like this: lnK2/K1 = -delta H naught/R * (1/T2 - 1/T1)

805329408
Posts: 49
Joined: Wed Nov 20, 2019 12:21 am

### Re: concept help

The Van't Hoff equation allows us to relate the equilibrium constant with temperature and also change in enthalpy and entropy.

Suraj Doshi 2G
Posts: 100
Joined: Fri Aug 02, 2019 12:15 am

### Re: concept help

The Van't Hoff equation is used to determine how temperature is affecting K. There are further derivations of the equation depending on which variables are known and constant. (A different equation for when deltaS is constant and when deltaH is constant)