Free Equilibrium Constant Shift Calculator
Calculate how the equilibrium constant K changes with temperature using the van't Hoff equation.
K
K
kJ/mol
K at Temperature T2
4.9870
K2 / K1 Ratio0.0499
K at Temperature T2 vs K at Temperature T1
Van't Hoff Equation
The van't Hoff equation predicts how the equilibrium constant changes with temperature.
Formula
ln(K2/K1) = (delta_H/R) × (1/T1 - 1/T2)
where R = 8.314 J/(mol·K) is the gas constant and delta_H is the reaction enthalpy.
This is the thermodynamic basis for Le Chatelier's principle regarding temperature.
Example Calculation
An exothermic reaction with K=100 at 298 K, delta_H = -50 kJ/mol. Find K at 350 K.
- 01ln(K2/K1) = (-50000/8.314) × (1/298 - 1/350)
- 021/298 - 1/350 = 0.003356 - 0.002857 = 0.000499
- 03ln(K2/K1) = -6013.4 × 0.000499 = -3.001
- 04K2/K1 = exp(-3.001) = 0.0498
- 05K2 = 100 × 0.0498 = 4.98
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