Unit 8: Chemical Reactivity
- The Arrhenius equation describes the relationship between:
- A) Activation energy and the reaction rate
- B) Temperature and reaction rate
- C) Catalyst concentration and reaction rate
- D) Product concentration and equilibrium constant
- Answer: B) Temperature and reaction rate
- Which of the following best describes a zero-order reaction?
- A) The rate of reaction is independent of the concentration of reactants.
- B) The rate of reaction is proportional to the concentration of reactants.
- C) The rate of reaction is proportional to the square of the concentration of reactants.
- D) The rate of reaction is dependent on the concentration of products.
- Answer: A) The rate of reaction is independent of the concentration of reactants.
- In a chemical reaction, what does a high rate constant indicate?
- A) The reaction is slow
- B) The reaction is fast
- C) The reaction is at equilibrium
- D) The reaction is non-spontaneous
- Answer: B) The reaction is fast
- The rate of a reaction increases when:
- A) The activation energy increases
- B) The temperature decreases
- C) The concentration of reactants increases
- D) The pressure decreases
- Answer: C) The concentration of reactants increases
- Which of the following describes the effect of a catalyst on a reaction mechanism?
- A) It changes the mechanism by introducing new reactants.
- B) It alters the overall enthalpy change of the reaction.
- C) It provides an alternative pathway with a lower activation energy.
- D) It affects the equilibrium constant of the reaction.
- Answer: C) It provides an alternative pathway with a lower activation energy.
- In a reaction where the rate law is rate = k[A][B], what happens if the concentration of A is doubled while the concentration of B remains constant?
- A) The rate of reaction is doubled
- B) The rate of reaction is quadrupled
- C) The rate of reaction is halved
- D) The rate of reaction remains unchanged
- Answer: A) The rate of reaction is doubled
- Which of the following would not affect the equilibrium position of a reaction?
- A) Change in temperature
- B) Change in pressure
- C) Addition of a catalyst
- D) Change in concentration of reactants
- Answer: C) Addition of a catalyst
- In the reaction A + B → C, if the reaction is first-order with respect to A and second-order with respect to B, what is the overall reaction order?
- A) Zero-order
- B) First-order
- C) Second-order
- D) Third-order
- Answer: D) Third-order
- What happens to the rate of a reaction if the temperature is decreased for an endothermic reaction?
- A) The rate increases
- B) The rate decreases
- C) The rate remains constant
- D) The rate becomes zero
- Answer: B) The rate decreases
- Which of the following is not a factor affecting reaction rate?
- A) Temperature
- B) Pressure
- C) Catalyst
- D) Volume of the container
- Answer: D) Volume of the container