COMPOSITE REACTIONS AND THE STEADY STATE APPROXIMATION

Review

For the concentration profile given below

Summary

General Strategy for dealing with Composite Reactions:

Step	Procedure
A	Determine if the reaction is elementary or composite by examining the experimental rate law.
B	If the reaction is composite, propose a reaction mechanism consistent with the experimental data.
C	Experimentally confirm the validity of the proposed reaction mechanism.
D	Derive a theoretical rate expression for the proposed reaction mechanism, which is consistent with the experimentally determined rate law.

The Steady State Approximation (SSA) is the setting of the rate of change of concentration of a species equal to zero. It is usually applied to the intermediate species, provided that the intermediate is highly reactive and present in low concentrations.