How to Calculate Vapor Pressure with Clausius-Clapeyron
Calculate liquid-vapor equilibrium metrics step-by-step:
Enter Base State P1 & T1
Input known vapor pressure P1 and boiling temperature T1 (e.g. 1 atm at 373.15 K).
Enter ΔHvap
Input molar enthalpy of vaporization ΔHvap in kJ/mol.
Enter Target Temp T2
Input target temperature T2 in Kelvin.
Compute P2 Pressure
Calculate new vapor pressure P2 in atm, mmHg, and kPa.
Key Features & Vapor Thermodynamics
Integrated Phase Transition Engine
Uses 2-point integrated Clausius-Clapeyron differential law.
Multi-Unit Pressure Output
Displays pressure in atmospheres, Torr/mmHg, and SI kilopascals (kPa).
Distillation & Vacuum Drying
Essential for chemical engineering vacuum distillation design.
Thermodynamics Guide: Clausius-Clapeyron Vapor Pressure
The Clausius-Clapeyron Equation describes the non-linear relationship between vapor pressure and temperature during liquid-gas phase change:ln(P2 / P1) = -(ΔHvap / R) × (1/T2 - 1/T1)
Frequently Asked Questions
?Is ΔHvap constant at all temperatures?
The standard Clausius-Clapeyron equation assumes ΔHvap is constant over small temperature intervals. Over wide temperature spans, ΔHvap decreases as temperature approaches the critical point.