enthalpy of sublimation
enthalpy of vaporization
ideal gas law constant
|ln (P/P°) =||H
The equation is easily derived from first principles. Several approximations are made to simplify the form of the equation:
Several of the assumptions fail at high pressure and near the critical point, and under those conditions the Clausius-Clapeyron equation will give inaccurate results. Chemists still like to use the equation because it's good enough in most applications and because it's easy to derive and justify theoretically.
Chemical engineers often use the more accurate Antoine equation to predict vapor pressures.
Author: Fred Senese firstname.lastname@example.org
Copyright © 1997-2010 by Fred Senese
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Last Revised 02/15/10.URL: http://antoine.frostburg.edu/chem/senese/101/liquids/faq/print-clausius-clapeyron-vapor-pressure.shtml