The objectives of the development that follows are to give the reader insight as to why the rate laws depend on the concentration of the reacting species (i.e., –rA = kCACB) and why the temperature dependence is the form of the Arrhenius law, k=Ae–/RT. To achieve this goal we consider the reaction of two molecules in the gas phase
We shall define our coordinate system such that molecule B is stationary wrt molecule A so that molecule A moves towards molecule B with a relative velocity UR. Molecule A moves through space to sweep out a collision volume with a collision cross section illustrated by the cylinder shown below.
C + D
illustrated by the cylinder shown below.
