Lecture 12 Lecture 12 Temperature and the Rates of Reaction Chemical reactions occur in a series of elementary steps, called a Reaction Mechanism . Molecularity is not the same as order . The order of of a reaction is the sum of exponents in the observed rate law for the overall reaction. The order can be zero, integral or fractional.
Most elementary steps involve a bimolecular collision between reactant molecules.
We have already demonstrated that the reaction rate will increase under these conditions, when we increase the concentration of the reacting molecules. This makes good sense. Statistically, the number of collisions should increase if the concentration of colliding species is increased. Another way to increase the frequency of collisions is to raise the Temperature of the system. Remember that Temperature is a measure of the average Kinetic Energy of the particles in the system.