Reversible reactions Knowledge-Based Practice

Questions

1. 1.

   Which of the following statements correctly describes how dynamic equilibrium can be established in a reversible reaction?

   • A) Dynamic equilibrium can only be established if the initial concentration of reactants is greater than that of products.
   • B) The forward reaction must go to completion before the reverse reaction can begin producing reactants.
   • C) Dynamic equilibrium can be established in an open container provided that temperature and pressure remain constant.
   • D) Dynamic equilibrium in a closed system can be established whether starting with pure reactants, pure products, or a mixture of both.
2. 2.

   Which observation provides experimental proof that a reversible reaction at chemical equilibrium is dynamic rather than static?

   • A) An isotopically labeled reactant added at equilibrium is incorporated into the products while total macroscopic concentrations remain unchanged.
   • B) Macroscopic physical properties such as color intensity, pressure, and temperature remain constant indefinitely in a closed container.
   • C) The reaction eventually proceeds until the limiting reactant is completely consumed and cannot be detected.
   • D) The rate of the forward reaction gradually decreases over time until it drops to an absolute value of zero.
3. 3.

   When pure reactants are introduced into a closed container at a constant temperature, how do the forward and reverse reaction rates change over time until dynamic equilibrium is established?

   • A) The forward rate increases and the reverse rate decreases until both reaction rates reach zero.
   • B) The forward rate decreases and the reverse rate increases until both reaction rates become equal.
   • C) Both the forward and reverse rates continuously increase until a steady rate is achieved.
   • D) The forward rate remains constant while the reverse rate increases until both rates match.
4. 4.

   Which of the following statements correctly defines a reversible chemical reaction?

   • A) The reactants are completely converted into products and cannot be reformed.
   • B) The products can react together under suitable conditions to reform the original reactants.
   • C) The forward process ceases entirely as soon as any product molecules begin to form.
   • D) The reaction requires a continuous external catalyst to proceed in either direction.
5. 5.

   Which of the following statements correctly describes a reversible reaction that has reached dynamic equilibrium in a closed system?

   • A) The forward and reverse chemical reactions have completely ceased.
   • B) The molar concentrations of the reactants and products must become identical.
   • C) The reaction has proceeded to completion because the limiting reactant is exhausted.
   • D) The rates of the forward and reverse reactions are equal, causing all concentrations to remain constant.

Answers and step-by-step solutions appear after you finish the test.