Question

clicker question
an increase in temperature increases the rate of a chemical reaction because
a. the activation energy is lower.
b. exothermic reactions are always favoured.
c. a greater fraction of particles have sufficient kinetic energy.
d. the particles are more likely to have a favourable collision geometry.
select an answer

Explanation:

• Option A: Activation energy is a property of the reaction itself and is not changed by temperature.
• Option B: Temperature increase does not always favor exothermic reactions. Le - Chatelier's principle shows that for exothermic reactions, increasing temperature actually shifts the equilibrium in the endothermic direction.
• Option C: According to the collision theory and the Maxwell - Boltzmann distribution, when temperature increases, the distribution of kinetic energy among particles changes. A greater fraction of particles have kinetic energy greater than or equal to the activation energy ($E_a$), leading to more effective collisions and a higher reaction rate.
• Option D: Collision geometry (related to the orientation of particles during collision) is not significantly affected by temperature changes. It is more related to the nature of the reactant molecules.

Answer:

C. a greater fraction of particles have sufficient kinetic energy.