16.2 Activation Energy

Which of the following statements best describes the activation energy of a reaction?

A. The energy required to break the bonds in the reactants.

B. The energy difference between the reactants and the products.

C. The minimum energy required for a reaction to occur.

D. The energy released when new bonds are formed in the products.

If the activation energy for a reaction is high, what can be inferred about the rate of the reaction?

A. The reaction will be fast.

B. The reaction will be slow.

C. The reaction will be exothermic.

D. The reaction will be endothermic.

Which component of the Arrhenius equation represents the frequency factor, indicating how often molecules collide?

A. k

B. Ea

C. R

D. A

In the Arrhenius equation, what does the term e^(-Ea/RT) represent?

A. The fraction of molecules with energy equal to the activation energy.

B. The fraction of molecules with energy greater than the activation energy.

C. The fraction of molecules with energy less than the activation energy.

D. The fraction of molecules with energy equal to the reaction energy.

How does an increase in temperature generally affect the activation energy of a reaction?

A. Increases the activation energy.

B. Decreases the activation energy.

C. Does not affect the activation energy.

D. Makes the activation energy zero.

a) Explain the significance of the energy profile diagrams in understanding the kinetics of a chemical reaction. [3]

b) How does the activation energy influence the rate of a chemical reaction? [2]

a) Describe the Arrhenius equation and its significance in the study of reaction rates. [3]

b) What is the physical meaning of the 'frequency factor' in the Arrhenius equation? [2]

a) How does a change in temperature affect the activation energy and the rate of a reaction? [3]

b) Briefly explain the concept of the 'transition state' in a chemical reaction. [2]

a) Describe the relationship between the activation energy of a reaction and its temperature sensitivity. [3]

b) How does a catalyst affect the activation energy of a reaction? [2]

c) Explain the significance of the Arrhenius plots in determining activation energies. [3]

a) What is the physical significance of the rate constant (k) in the context of reaction kinetics? [3]

b) Using the Arrhenius equation, explain how the rate constant varies with temperature. [3]

c) Define the term 'molecularity' and explain its relevance in reaction mechanisms. [2]