Question

Which factor in the Arrhenius equation corresponds to the fraction of molecules having kinetic energy greater than activation energy?

• A. ln k
• B. ln A
• C. RT
• D. e^-Ea/RT

Answer 1

The Correct Option is D

The Arrhenius equation is expressed as: k = Ae^-Ea/RT, where: 

• k is the rate constant.
• A is the pre-exponential factor (frequency factor).
• E_a is the activation energy.
• R is the universal gas constant.
• T is the temperature in Kelvin.

The term e^-Ea/RT in the Arrhenius equation represents the fraction of molecules with kinetic energy greater than the activation energy. This term arises from the exponential decay of molecular energy distribution and describes how increasing temperature or decreasing activation energy increases this fraction.

Therefore, the specified component corresponding to the fraction of molecules having kinetic energy greater than activation energy is indeed e^-Ea/RT.

Answer 2

The Arrhenius equation describes how the rate constant \( k \) of a chemical reaction depends on temperature and activation energy. It is given by:

\(k = A e^{\frac {-E_a}{RT}}\)where:

• \( k \) = rate constant
• \( A \) = frequency factor
• \( E_a \) = activation energy
• \( R \) = universal gas constant
• \( T \) = temperature in Kelvin

The factor \( e^{-E_a/RT} \) in the equation \( k = A e^{-E_a/RT} \) is crucial. Here, \( e^{-E_a/RT} \) represents the fraction of molecules with kinetic energy greater than the activation energy \( E_a \). This term indicates the probability of a molecule possessing enough energy to undergo a reaction when colliding.

Hence, the correct factor is: e^-Ea/RT