Question

Answer the following in brief.

Explain graphically the effect of temperature on the rate of reaction.

Answer 1

i. The average kinetic energy of molecules is proportional to temperature.

ii. At a given temperature, the fraction of molecules with their kinetic energy equal to or greater than E_a may lead to the product.

iii. With an increase in temperature, the fraction of molecules having their energies (E_a) would increases. The rate of the reaction thus would increase.

iv. This is depicted by plotting a fraction of molecules with given kinetic energy versus kinetic energy for two different temperatures T₁ and T₂ (T₂ > T₁). The area between the curve and the horizontal axis is proportional to the total number of molecules. The total area is the same at T₁ and T₂.

Comparison of fraction of molecules activated at T₁ and T₂

v. The entire shaded area which represents a fraction of molecules with kinetic energy exceeding E_a is larger at T₂ than at T₁ (since T₂ > T₁).

vi. This indicates that a fraction of molecules possessing energies larger than E_a increase with temperature. The rate of reaction increases accordingly.