Unit 11: Reaction Kinetics

11. What does the rate of a chemical reaction refer to?

a) The amount of heat released
b) The amount of time taken for the reaction to complete
c) The change in concentration of reactants or products per unit time
d) The volume of the reaction mixture
Answer: c) The change in concentration of reactants or products per unit time

12. Which of the following factors does NOT affect the rate of a chemical reaction?

a) Temperature
b) Concentration of reactants
c) Pressure
d) The color of the reactants
Answer: d) The color of the reactants

13. According to the collision theory, for a reaction to occur, particles must:

a) Collide with sufficient energy and proper orientation
b) Be at a high temperature
c) Be in a gaseous state
d) Have the same mass
Answer: a) Collide with sufficient energy and proper orientation

14. The minimum energy required for a reaction to occur is called:

a) Activation energy
b) Potential energy
c) Kinetic energy
d) Binding energy
Answer: a) Activation energy

15. How does increasing the temperature affect the rate of a chemical reaction?

a) It decreases the rate
b) It has no effect on the rate
c) It increases the rate
d) It doubles the rate
Answer: c) It increases the rate

16. What is the effect of increasing the concentration of reactants on the rate of reaction?

a) It decreases the rate
b) It has no effect on the rate
c) It increases the rate
d) It makes the reaction slower
Answer: c) It increases the rate

17. The rate law of a reaction expresses the relationship between the rate of reaction and:

a) The amount of catalyst used
b) The concentration of reactants
c) The temperature of the reaction
d) The pressure of the reaction
Answer: b) The concentration of reactants

18. In the rate law equation, the exponent of the concentration term represents:

a) The rate constant
b) The order of the reaction with respect to that reactant
c) The activation energy
d) The rate of the reaction
Answer: b) The order of the reaction with respect to that reactant

19. What is the unit of the rate constant (k) for a first-order reaction?

a) s⁻¹
b) M⁻¹s⁻¹
c) M⁻²s⁻¹
d) M/s
Answer: a) s⁻¹

20. For a second-order reaction, the rate law is generally expressed as:

a) Rate = k[A]
b) Rate = k[A][B]
c) Rate = k[A]²
d) Rate = k[A][B]²
Answer: b) Rate = k[A][B]