Trouton's rule


Trouton's rule
The statement that, for most liquids, the enthalpyA thermodynamic state function, symbol H, that equals internal energy plus pressure x volume; the change in enthalpy corresponds to the energy transferred as a result of a temperature difference (heat transfer) when a reaction occurs at constant pressure. of vaporizationThe formation of a vapor from a liquid; evaporation or boiling. divided by the boilingThe process of a liquid becoming vapor in which bubbles of vapor form beneath the surface of the liquid; at the boiling temperature the vapor pressure of the liquid equals the pressure of the gas in contact with the liquid. temperatureA physical property that indicates whether one object can transfer thermal energy to another object. (in kelvins) has a nearly constant value of 75 to 80 J K-1 mol-1; that is, the entropyA thermodynamic state function, symbol S, that equals the reversible heat energy transfer divided by temperature; higher entropy corresponds to greater dispersal of energy on the molecular scale. See also standard entropy. of vaporization of a liquid is approximately constant.