The equations are basically a mathematical definition of A (collision frequency) and a more complex version of

. I am 99% that you only be using the this equation and not the one that they give you in section 15.12.

As for what you should know from the section, simply know the basics of collision theory. Molecules have to collide with enough energy to overcome the energy barrier Ea. If not, the molecules will simply bounce apart.

If the reaction is endothermic, the activation energy for the forward direction is higher than that for the reverse. Conversely, if the reaction is endothermic, the activation energy for the forward direction is less than that for the reverse. This can be seen in a reaction profile and by the equation

where k is the rate constant of the forward reaction and k' is the rate constant of the reverse reaction.