Vapor Pressure Calculator
Calculate vapor pressure using Antoine Equation or Clausius-Clapeyron Equation
About Vapor Pressure
Antoine Equation
The Antoine equation is a class of semi-empirical correlations describing the relation between vapor pressure and temperature for pure substances.
log10(P) = A – B/(T + C)
Where P is vapor pressure in mmHg, T is temperature in °C, and A, B, C are substance-specific constants.
Clausius-Clapeyron Equation
The Clausius-Clapeyron equation relates the vapor pressures of a substance at two different temperatures to the enthalpy of vaporization.
ln(P₂/P₁) = -ΔHvap/R * (1/T₂ – 1/T₁)
Where P is vapor pressure, T is temperature in Kelvin, ΔHvap is enthalpy of vaporization, and R is the gas constant.