Chapter Three - Reaction Rate Expression

Abstract

This chapter discusses the chemical reaction rate expression and the various variables that influence the reaction rate. Chemical kinetics analyzes the dynamics of chemical reactions. The raw data of chemical kinetics are the measurements of the reactions rates. The equations are used to arrive at an expression that relates measurable parameters of the reactions to constants and to concentration terms. The rate of reaction is defined as an intensive variable and is independent of any particular reactant or product species. As the reaction rate changes with time, the time derivative can be used to express the instantaneous rate of reaction because it is influenced by the composition and temperature. The rate of a chemical reaction depends on the temperature, pressure, and composition of the system under investigation, certain species that do not appear in the stoichiometric equation for the reaction can affect the reaction rate even when they are present in only trace amounts. For a system in which both forward and reverse reactions are important, the net rate of reaction is expressed as the difference between the rate in the forward direction and that in the opposite direction.