A correlation formula to estimate chemical exergies of oil fractions and fu
el mixtures from enthalpy of combustion and atomic composition is developed
. Heat capacity of a mixture of 10 hydrocarbons was measured in the range 5
-290 K. It was shown that contribution of entropy of mixing to exergy of ty
pical oil fractions is about -0.11% in the approximation of ideal solution,
and about -0.18% for a real solution.