Back to the modes and laws of kinetics

The main kinetic modes provide comparatively complex reaction rate laws, the results of which depend on the type of mode chosen. The experimental comparison of these laws is one of the aspects of mechanism validation. 

Modes with a single rate-determining step 

Such modes are obtained by writing the pseudo-steady state and that each step, except the rate-determining step, are at equilibrium. 

Such a mode provides a rate law that is the product of one kinetic term and the distance from the equilibrium conditions, with the kinetic term being the reaction rate when the reaction is far from the equilibrium. 

By applying the law of mass action for all the non-rate-determining steps, the reaction rate far from the equilibrium is such that it often admits an order with respect to some reactants and/or products. In this case, concentrations of the different reagents and products are separate variables apart from each other and from temperature. Only catalytic sequences such as adsorption disturb these properties. 

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