The Spillover of Chemisorbed Species

Thermodynamics and Rate.—In a system undergoing r simultaneous independent reactions in several phases, the set of stoicheiometric equations can be written  

From De Bonder s inequality, Adi 0, relating the extent of reaction i to the function of state called the affinity (A) of the reaction, one gets 

Thus the rate of the pth reaction has always the same sign as the affinity and if the affinity is zero the system is in equilibrium and the rate is zero. Because 

The intermediate reactions are the adsorptions, desorptions, and other interactions involving adsorbed states. Similarly, for catalysed reactions which are not explicitly coupled in their stoicheiometric equation, e.g. 

If the reaction involves transport in the adsorbed state from one chemically distinct adsorption site to another then these processes ( gAaK) must also be included— 

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