Top

Activation Energy Calculator
Top
Activation energy concept was given by Swedish scientist Svante Arrhenius in 1889. It is the energy required by the reactant to undergo the chemical reaction and form products.
It is given as:
Ea = - RT ln $\frac{k}{A}$
Where R = gas constant
T = Temperature (in Kelvin)
K = rate constant
A = Frequency factor of the reaction.
Activation Energy Calculator calculates the activation energy Ea if temperature T, rate constant (K) and frequency factor A are given. The value k is used to determine the rate of the reaction.

## Steps for Activation Energy Calculator

Step 1 :

Read the given problem and list out the given quantities.

Step 2 :

Ea = - RT ln $\frac{k}{A}$
Substituting the values in the above formula, we get the answer.

## Problems on Activation Energy Calculator

1. ### If rate constant of the reaction is 4 $\times$ 10-4 s-1. If the temperature is 30oC and frequency factor is 2.5 $\times$ 1011 s-1. Calculate its activation energy?

Step 1 :

given: Rate constant k = 4 $\times$ 10-4 s-1,
Temperature T = 30oC = 303 K,
Frequency factor A = 2.5 $\times$ 1011 s-1,
Activation energy Ea =?

Step 2 :

The activation energy is given by Ea = - RT ln $\frac{k}{A}$

= - 8.314 $\times$ ln $\frac{4 \times 10^{-4}}{2.5 \times 10^{11}}$

= - 8.314 $\times$ ln (1.6 $\times$ 10-15)

= -8.314 $\times$ 303 $\times$ (- 36.33)

= 283.247 $\times$ 303

= 85828.95 J/mol.

The activation energy for the reaction is 85828.95 J/mol = 85.828 KJ/mol.

2. ### If rate constant of the reaction is 5 $\times$ 10-5 s-1. If the temperature is 35oC and frequency factor is 3 $\times$ 1011s-1. Calculate its activation energy?

Step 1 :

given: Rate constant k = 5 $\times$ 10-5 s-1,
Temperature T = 35oC = 308 K,
Frequency factor A = 3 $\times$ 1011 s-1,
Activation energy Ea = ?

Step 2 :

The activation energy is given by
Ea = - RT ln $\frac{k}{A}$
= - 8.314 $\times$ ln $\frac{5 \times 10^{-5}}{3 \times 10^{11}}$

= - 8.314 $\times$ 308 $\times$ ln(1.66 $\times$ 10-16)

= 93037.322 J/mol.