The activation energy, E_a, is the minimum energy required by the reactants to form the products. It is determined by measuring the rate constant at various temperatures. The plot of ln(k) (y) versus 1/T (x) should yield a straight line with the slope = -E_a/R (R = 8.314 J K^-1 mol^-1). For the decomposition of H₂O₂:

Temperature (K)	Rate constant (mol L-1 sec-1)
317	0.00002861
339	0.0001766
362	0.0009346
378	0.002643

From these data, plot of ln(k) versus 1/T and determine the slope and calculate E_a (check units)

slope =	K
Ea =	kJ mol-1