A certain reaction has an enthalpy of Δ𝐻=−34 kJ and an activation energy of 𝐸a=53 kJ. What is the activation energy of the reverse reaction?

Answer 1

Since the ∆H is negative 34 kJ, this means that it is lower than the starting value for the reactants. Thus, the reverse reaction will have a higher "hill" to climb, i.e. greater activation energy. The answer to this problem is

53 kJ + 34 kJ = 87 kJ = activation energy of reverse reaction