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breaking of bond in the chemical reaction which also require some minimum amount of energy. The energy

can be in the form of Potential energy or Kinetic energy or both.

This minimum energy which requires to starting the reaction is called the activation energy. We represent it

by “Ea”.

We use the Arrhenius equation to derive formula for activation energy.

K = A e^-Ea/RT

Thus, ln K = -Ea/RT + ln A

Where, K = Rate constant

A = Frequency factor

R = gas constant

T = absolute temperature

If we have rate constant K1 and K2 at Temperature T1 and T2, the activation energy formula will be:

Log(K2/K1) = - Ea/2.303R (T2 – T1)/T1T2

Calculate the activation energy of the reaction at 45

Rate constant, K = 6.0 × 10^-4S^-1

Frequency factor, A = 3.621 × 10^13 S^-1

Temperature, T = 45

So absolute temperature = 273 + 45 = 318

Now we have the formula for activation energy:

Log K = Log A – Ea/2.303RT

Log(6.0 × 10^-4) = Log (3.621 × 10^13) – Ea/2.303(8.314)(318)

Therefore, Ea = 111657 J = 112 KJ

energy of activation of the reaction assuming that it does not change with temperature.

And T1 = 295, T2 = 308

Now, use the formula

Log(K2/K1) = - Ea/2.303R (T2 – T1)/T1T2

Log(2K2/K1) = -Ea/2.303R (308-295)/308*295

Log 2 = -Ea/2.303*8.314 (13)/90860

Therefore, Ea = 40,285 Jmol^-1 = 40 KJ mole^-1