The frequency factor determines the maximum rate of collisions, is a function of particle size, concentration and the rate of diffusion. The steric factor accounts for orientation, in that not all collisions have the correct orientation to result in a reaction, (see video 14.6.214.6.2\PageIndex{2}). The rule of thumb is that the more symmetric a molecule the larger the steric factor (a value of 1 means there is no effect, and the pre-exponential is determined by the collision frequency) and the more complicated a molecule, the smaller the steric factor (which is less than one), because only a fraction of the collisions have the correct orientation.

Concentration Conversions