Premium
A Descriptive Approach to Gibbs Fundamental Equation and Equilibrium Conditions in Reacting Multi‐component Systems based on the First and Second Law of Thermodynamics
Author(s) -
Klein H.
Publication year - 2009
Publication title -
chemical engineering and technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.403
H-Index - 81
eISSN - 1521-4125
pISSN - 0930-7516
DOI - 10.1002/ceat.200900237
Subject(s) - thermodynamics , enthalpy , gibbs free energy , gibbs–helmholtz equation , chemical thermodynamics , chemistry , work (physics) , laws of thermodynamics , entropy (arrow of time) , chemical equilibrium , standard molar entropy , chemical equation , second law of thermodynamics , component (thermodynamics) , statistical physics , non equilibrium thermodynamics , physics
The Gibbs fundamental equation for multi‐component systems can be derived directly from the first and second law of thermodynamics. This approach has been outlined already by Haase [1], but the approach adopted in that work required the assumption that, besides dissipation of mechanical work, chemical reactions contribute to a generation of entropy within the system. In this paper, a derivation is presented, which shows that the expression for the entropy generation arises automatically without any further assumptions. It is shown that the correct driving forces for chemical reactions can be obtained over the whole composition range only if the adequate caloric equation of state for the molar entropy is used for the components in the mixture. Two chemical reactions of industrial importance are presented to show this impact over the entire range of educt and product compositions. Furthermore, it is shown that the different approaches based on molar free enthalpy of reaction as the driving force of chemical reactions, minimum Gibbs free enthalpy and functional equations based on equilibrium constants, are inherently similar since all of them reflect more or less the second law of thermodynamics.