Evaluation of thermodynamic functions from equilibrium constants

Abstract

A new family of completely general equilibrium equations has been developed to represent the temperature dependence of reaction equilibrium constants in terms of the reaction standard thermodynamic function changes at a chosen reference temperature. Evaluation of these equilibrium equations by the method of least squares provides the best unbiased estimates for the standard thermodynamic function changes and their standard errors which are readily determined for the first time. Application of the equations to the ionization of aqueous cyanoacetic acid furnishes a more general representation of the data than comparable empirical relations. Use of the new equations is recommended when it is required to predict both the values and errors on standard thermodynamic function changes from the temperature dependence of reaction equilibrium constants.