# In the equation k = ZAB e-Ea /RT, what does e-Ea /RT represent?

e-Ea/RT represents the fraction of molecules with energies equal to or greater than Ea.

### Chemical kinetics and rate of a reaction

In chemical kinetics, the pre-exponential factor or A factor is the pre-exponential constant in the Arrhenius equation, an empirical relationship between temperature and rate coefficient.

Chemical kinetics says the speed or rate at which a reaction occurs :

The rates of reactions are affected by

• Reactant concentration.
• Temperature.
• Reactant states.
• Catalysts.

In the reaction A + B → AB

The rate of the reaction is equal to the number of active collisions. So the rate of reaction can be written as

ZAB e-Ea/RT

E: is the activation energy (J/mol)A is the frequency factor, a number that represents the likelihood that collisions would occur with the proper orientation

T: is the temperature in Kelvin for reaction.

R: Gas constant