The Arrhenius equation
T = temperature in kelvin Exponential form R = gas constant = 8.314 J K–1 mol–1 T = temperature in kelvin Exponential factor, e–Ea/RT: proportion of molecules that have sufficient energy for a reaction to take place Pre-exponential term (frequency factor), A, accounts for the frequency of collisions with the correct orientation
intercept on the y-axis, c = ln A. Logarithmic form A plot of ln k against 1/T gives a downward straight line graph of the type y = mx + c gradient m = –Ea/R intercept on the y-axis, c = ln A.
Graph of ln k against 1/T
Ea from an Arrhenius plot