# What are the dimensions of A in the expression k = Ae-Ea/RT?

A is a pre-exponential factor and is equal to the number of collisions per unit of time.

### Explanation

The given equation is called the Arrhenius equation. The Arrhenius equation is an expression that provides a relationship between the rate constant (of a chemical reaction), the absolute temperature, and the A factor (also known as the pre-exponential factor; can be imagined as the frequency of correctly oriented collisions between reactant particles). It provides insight into the dependence of reaction rates on the absolute temperature. The expression of the Arrhenius equation is:

k = Ae-Ea/RT

Where,

k denotes the rate constant of the reaction
A denotes the pre-exponential factor which, in terms of the collision theory, is the frequency of correctly oriented collisions between the reacting species
e is the base of the natural logarithm (Euler’s number)
Ea denotes the activation energy of the chemical reaction (in terms of energy per mole)
R denotes the universal gas constant
T denotes the absolute temperature associated with the reaction (in Kelvin)

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