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What do the frequency factor and activation energy represent in the Arrhenius equation?

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A graph showing a potential energy curve for a chemical reaction, with the y-axis labeled potential energy and the x-axis labeled progress of reaction. The curve rises from the initial state (reactants) to a peak labeled transition state (activated complex), indicating activation energy, then drops to the final state (products).
chemical kinetics In the Arrhenius equation, the activation energy (E) represents the minimum amount of energy required to transform reactants into products in a chemical reaction. On a potential energy curve, the value of the activation energy is equivalent to the difference in potential energy between particles in an intermediate configuration (known as the activated complex, or transition state) and particles of reactants in their initial state. The activation energy thus can be visualized as a barrier that must be overcome by reactants before products can be formed.

In the Arrhenius equation, which describes how temperature influences the rate of a chemical reaction, the parameters A and E represent fundamental kinetic properties of a reaction.12

The Frequency Factor (A)

Also known as the pre-exponential factor, A represents the frequency at which atoms and molecules collide in an orientation that leads to a reaction. It accounts for the total number of collisions and the probability that those collisions are effectively aligned to result in a chemical transformation.132

Activation Energy (E)

The activation energy (E) represents the minimum energy threshold that reactants must overcome to undergo a chemical change. It reflects the energy barrier between the initial state of the reactants and the high-energy activated complex (or transition state). According to the Boltzmann principle, the term exp(−E/RT) represents the fraction of molecules possessing sufficient energy to surpass this barrier; collisions between molecules with energy less than E are ineffective, and the reactants remain unchanged.32