Van’t Hoff Equilibrium Temperature

The Van’t Hoff equation describes how the equilibrium constant of a chemical reaction changes with temperature. Assuming the standard reaction enthalpy is constant over the given temperature range, this equation connects thermodynamics to the observed equilibrium states without invoking kinetic rates or activation energy.

Experiment Simulation

Interact with the Van’t Hoff Equilibrium Temperature controls to see how enthalpy and temperature determine the equilibrium constant.

1. Set Reference K to 10, Enthalpy kJ per mol to 40, and Temperature kelvin to 350. Observe that Log equilibrium K is 4.692991306152466 and Equilibrium K increases to 109.17928048420983.
2. Set Enthalpy kJ per mol to -40. Notice the Equilibrium K drops to 0.9159247025305566, and the Log-K temperature slope becomes negative (-0.03927260572823708).
3. Set Reference K to 1. The Equilibrium K becomes 10.917928048420976 and Log equilibrium K shifts to 2.39040621315842. Standard Gibbs energy changes to -6956.230085527424.
4. Set Temperature kelvin to 298.15. See that Equilibrium K matches the reference exactly (10.000000000000002 due to precision), and Log equilibrium K is 2.302585092994046.
5. Set Enthalpy kJ per mol to 0. The Log-K temperature slope becomes 0.0, and Equilibrium K remains fixed at the reference value regardless of the temperature.