A reaction can proceed by an uncatalyzed or a catalyzed pathway. Activation energies for each elementary step are listed below (all energies relative to the reactants at 0 kJ).
Ea (uncatalyzed) Ea (catalyzed)
Step 1 80 kJ 40 kJ
Step 2 60 kJ 55 kJ
Step 3 90 kJ 50 kJ
Calculate the decrease (in kJ) in the energy of the rate-determining transition state when the catalyst is present.