Interpretation of Arrhenius Equation
Arrhenius equation represents the dependence of the rate constant k of a reaction on the absolute temperature T:
where the factor refers to the fraction of collisions (also effective collisions) that have the sufficient activation energy to collide and form products and A is the number of effective collision per unit time. Therefore, the product of A and is the number of collisions that actually lead to the formation of products.
Determination of activation energy
where k1 and k2 are rate constants at temperatures T1 and T2 kelvin, respectively. Knowing these values, Ea can be calculated. Care must be taken to insert the value of R in a unit in which Ea is desired.
Main characteristics of arrhenius equation
- The larger the activation energy of a reaction, the smaller is the value of rate constant.
- The larger the activation energy of a reaction, the greater is the influence of change in temperature on rate constant.
- For lower temperature range, increase in temperature causes more change in the value of k than the same increase in temperature of high temperature range.