De Donder’s affinity

GENERAL FREE ENERGY CHANGES DE DONDER S AFFINITY 285... 

A more general picture of the free energy driving forces accompanying chemical reaction can be given in terms of de Donder s affinity 4, defined as... 

De Donder s affinity has an entirely different conceptual basis it relates entropy to irreversible chemical processes that occur in nature. It is clearly a more general view of entropy, one which does not restrict the idea of entropy to infinitely slow (quasistatic) reversible processes and equilibrium states. 

This definition of affinity is essentially due to De Donder and is called De Donder s fundamental inequality. In the notation used by G.N. Lewis and his school, it is supposed that increases by unity therefore the relations of (2) are written in the form ... 

The introduction of affinity by De Donder marks the birth of the Brussels school the first publication appeared around 1922, but it took some years to make these concepts more precise.4 What was the reaction of the scientific community When we go through the proceedings of the Belgian Royal Academy, we see that De Donder s work indeed aroused much local interest. Verschaffel from Ghent and Mund from Louvain were among the people who became active in this newborn nonequilibrium chemical thermodynamics. However, one has to say that elsewhere De Donder s approach met with skepticism and even with hostility. His introduction of affinity was thought of as merely a different notation. 

Indeed, suppose that it is otherwise, and that >0, for example. De Donder s inequality for the disturbed system, if we discount the variation of the affinity, gives us ... 

The molar reaction Gibbs function ArG quantity, whose algebraic sign has been inversed, is called the chemical affinity (de Donder s definition). It is positive for a spontaneous process ... 

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