A method to evaluate the enthalpy of reaction aided by cubic equations of state was developed. The method is based on its definition, as the stoichiometric combination of partial molar enthalpies of every compound involved in the reaction. Partial molar enthalpy can be evaluated by subtracting the partial molar residual enthalpy from the ideal gas enthalpy as pure compound. Then, the partial molar residual enthalpy would be calculated by means of expressions obtained in this work from cubic equations of state within a generic algebraic shape. As side result, expressions to evaluate partial molar volume were obtained which can be useful in modeling of separation processes like reverse osmosis or pervaporation. (c) 2006 Elsevier B.V. All rights reserved.