ABSTRACT
This chapter describes the equations used to define rates of chemical reactions. It also describes rate equations for simple one-step reactions that proceed to completion in closed systems, and then proceed to more complicated cases important in natural waters: reversible, consecutive, and chain reactions. Rates of chemical reactions depend on the nature of the reactants, their concentrations, and physical conditions such as temperature. Kinetic parameters commonly are evaluated from time course data for a reaction and plots of observed concentrations vs. time according to the integrated rate expressions. The simplest way to estimate rate constant values is to use rate expressions integrated over discrete time intervals. Rates of reactions depend on physical conditions as well as on reactant concentrations, and these conditions must be controlled if valid data are to be obtained. Kinetic studies deal with changing concentrations of reactants and products in inherently unstable situations.
