校准曲线计算器 — 公式
## 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.
- Exothermic reactions (delta_H < 0): K decreases as T increases
- Endothermic reactions (delta_H > 0): K increases as T increases
This is the thermodynamic basis for Le Chatelier's principle regarding temperature.
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.
- Exothermic reactions (delta_H < 0): K decreases as T increases
- Endothermic reactions (delta_H > 0): K increases as T increases
This is the thermodynamic basis for Le Chatelier's principle regarding temperature.
计算示例
An exothermic reaction with K=100 at 298 K, delta_H = -50 kJ/mol. Find K at 350 K.
- ln(K2/K1) = (-50000/8.314) × (1/298 - 1/350)
- 1/298 - 1/350 = 0.003356 - 0.002857 = 0.000499
- ln(K2/K1) = -6013.4 × 0.000499 = -3.001
- K2/K1 = exp(-3.001) = 0.0498
- K2 = 100 × 0.0498 = 4.98