Lesson 4.6.2.3

4.6.2.3 Equilibrium Quiz: AQA Chemistry, Unit 6

20 questions

Written by Revision Ninja · Last reviewed 11 October 2026

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Lesson 4.6.2.3, Equilibrium: 20 multiple choice questions for the AQA GCSE Chemistry (8462), Unit 6: The rate and extent of chemical change, written with Revision Ninja.

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The 20 questions

  1. When is chemical equilibrium reached in a closed system?

    • Equal rates
    • Zero forward rate
    • Equal concentrations
    • Reaction stops

  2. What type of apparatus is required for a reversible reaction to reach equilibrium?

    • Boiling tube
    • Evaporating basin
    • Closed system
    • Open beaker

  3. At equilibrium, the concentrations of reactants and products:

    • Become zero
    • Remain constant
    • Change continuously
    • Are always equal

  4. What happens to the forward and reverse reactions at equilibrium?

    • Only reverse continues
    • Only forward continues
    • Both stop
    • Both continue

  5. What is true about reactant and product concentrations at equilibrium?

    • Zero
    • Equal
    • Decreasing
    • Constant

  6. The forward rate is 4 units and the reverse rate is 4 units. The system is:

    • At equilibrium
    • Reacting only backward
    • Reacting only forward
    • Not at equilibrium

  7. The forward rate is 5 units and the reverse rate is 3 units. What is the net direction?

    • Net reverse reaction
    • Equilibrium
    • Net forward reaction
    • No reaction

  8. What characterizes a dynamic equilibrium in a reversible reaction?

    • Stopped reactions
    • Equal masses
    • Equal rates
    • Zero energy

  9. At equilibrium, what is the relationship between forward and reverse reaction rates?

    • Reverse is faster
    • Both are zero
    • They are equal
    • Forward is faster

  10. According to Le Chatelier's principle, how does increasing temperature affect an endothermic forward reaction?

    • Shifts to product side
    • No effect on equilibrium
    • Shifts to reactant side
    • Stops the forward reaction

  11. From which starting points can a reversible reaction reach equilibrium in a closed system?

    • Products only
    • Reactants or products
    • Catalysts only
    • Reactants only

  12. A reaction at equilibrium has forward and reverse rates of 2 mol/s each. What is the net change?

    • 2 mol/s
    • 4 mol/s
    • Negative
    • Zero

  13. In a closed flask at equilibrium, what happens to the total mass?

    • It becomes zero
    • It remains constant
    • It halves
    • It changes

  14. Which feature makes equilibrium reached more quickly?

    • Adding a catalyst
    • Opening the container
    • Letting gas escape
    • Cooling to zero

  15. Why is equilibrium never reached in an open system?

    • Catalyst is missing
    • Temperature is constant
    • Reaction is irreversible
    • Substances escape

  16. What feature defines a chemical system at equilibrium?

    • Equal rates
    • Equal masses
    • Equal concentrations
    • Stopped reactions

  17. Which graph feature shows that a reversible reaction has reached equilibrium?

    • Steepest gradient
    • Curves levelling off
    • Lines going to zero
    • Curves intersecting

  18. Which words complete the statement: at equilibrium, forward and reverse reactions occur ___ rates?

    • At zero
    • At the same
    • At different
    • At higher

  19. What happens to reactant and product concentrations in a closed system at equilibrium?

    • They drop to zero
    • They continuously increase
    • They fluctuate rapidly
    • They remain constant

  20. Which best describes equilibrium as a process?

    • A stopped reaction
    • A decomposition only
    • A static state
    • A dynamic state

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