Consider a complex reaction taking place in three steps with rate constants k1, k2 and k3 respectively. The overall rate constant k is given by the expression k= k1k3k2. If the activation energies of the three steps are 60, 30 and 10 kJ mol-1 respectively, then the overall energy of activation in kJ mol-1 is . (Nearest integer)
Answer
20
Solution
k=Ae-Ea/RT: products add, quotients subtract, root halves Ea
Ea= 12(E1+E3-E2)
= 12(60+10-30)=20 kJ mol-1
Answer: 20