Conceptual Van't Hoff Equation

[Elena Chen 2E]

Hi, could someone please explain conceptually what the Van't Hoff equation actually is and how we know when to use it? Thanks!

[Chanel Mao 3D]

Hi Elena!
The Van't Hoff Equation basically helps calculate K at different temperatures when there is a given enthalpy change. For problems regarding the Van't Hoff Equation, we would usually need a Temperature 1 and Temperature 2 value as well as a change in enthalpy in order to solve for the K value after the temperature change. Hope this helps!

[anikamenon2H]

The Van't Hoff Equation also illustrates the temperature dependency of the equilibrium constant because if you calculate K at two different temperatures, you get two different values, hence the basis for this equation.

[David Chibukhchian 2G]

I definitely agree with the other answers and would just add that the enthalpy value may not be given, in which case we might have to find it ourselves (for example, by using a list of standard enthalpies of formation) and then apply it to the Van't Hoff Equation. Also, be careful to convert that value to Joules because enthalpy is often given in kJ. I hope that helps!