Chemical kinetics, an important branch of physical chemistry is the study of Chemical reactions and is well researched all over the world. It includes investigations of how different experimental conditions can influence the speed of a chemical reaction and yield information about the reactions mechanism and transition states, as well as construction o f mathe-matical models that can describe the characteristics of a chemical reaction. Chemical reactions vary greatly in the speed at which they occur. Some are instantaneous, while others may take years to reach equilibrium. Reaction rate for a given chemical reaction is change in concentration of reactants or change in concentration of products per unit time. The ex-perimental determination of reaction rates involves how the concentration of reactants or products changes over time. For example, the concentration of a reactant can be measured by spectrophotometer at a wavelength where no other reactant or product in the system absorbs light. For reactions which take several minutes, it is possible to start observation after the reactants have been mixed at temperature of interest.

Physical Chemistry, Equilibrium, Spectrophotometer, Temperature etc.