Equations to Describe Kinetics of Reactions on Soil Constituents

EQUATIONS TO DESCRIBE KINETICS OF REACTIONS ON SOIL CONSTITUENTS 

A number of equations have been used to describe the kinetics of soil chemical processes (see, e.g., Sparks, 1985, 1986). Many of these equations offer a means of calculating rate coefficients, which then can be used to determine energies of activation (E), which reveal information concerning rate-limiting steps. Energies of activation measure the magnitude of forces that must be overcome during a reaction process, and they vary inversely with reaction rate. 

However, as noted earlier, conformity of kinetic data to a particular equation does not necessarily mean it is the best model, nor can one propose mechanisms based on this alone. 

Derivations. According to the usual convention, one lets a represent the initial concentration [A]0, of species A, b the initial concentration [B]0, of species B, and y the concentration of product Y or Z [see Eq. (2.1)] at 

Equations to Describe Kinetics of Reactions on Soil Constituents 

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Differential Rate Laws 5 Mechanistic Rate Laws 6 Apparent Rate Laws 11 Transport with Apparent Rate Law 11 Transport with Mechanistic Rate Laws 12 Equations to Describe Kinetics of Reactions on Soil Constituents 12 Introduction 12 First-Order Reactions 12 Other Reaction-Order Equations 17 Two-Constant Rate Equation 21 Elovich Equation 22 Parabolic Diffusion Equation 26 Power-Function Equation 28 Comparison of Kinetic Equations 28 Temperature Effects on Rates of Reaction 31 Arrhenius and van t Hoff Equations 31 Specific Studies 32 Transition-State Theory 33 Theory 33... 

Equations to Describe Kinetics of Reactions on Soil Constituents Two-Constant Rate Equation... 

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