Lesson 5.6.2.3

5.6.2.3 Equilibrium Quiz: AQA Combined Science, Unit 13

20 questions

Written by Revision Ninja · Last reviewed 11 October 2026

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Lesson 5.6.2.3, Equilibrium: 20 multiple choice questions for the AQA GCSE Combined Science (8464), Unit 13: The rate and extent of chemical change, written with Revision Ninja.

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The 20 questions

  1. What happens to the forward and reverse rates when equilibrium is reached in a closed system?

    • Reverse rate stops
    • Rates become equal
    • Forward rate increases
    • Rates become zero

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

    • Closed system
    • Heated crucible
    • Evaporating dish
    • Open beaker

  3. At equilibrium, are reactant and product concentrations necessarily equal?

    • Yes, always equal
    • Only products remain
    • Only reactants remain
    • No, not necessarily

  4. What is equal during dynamic equilibrium in a closed system?

    • Product volumes
    • Activation energies
    • Reactant masses
    • Opposing rates

  5. Why can an open container not achieve dynamic equilibrium in a reversible reaction?

    • Reactants freeze
    • Pressure drops
    • Products escape
    • Temperature rises

  6. At equilibrium the forward rate is 4 mol/s. What is the reverse rate?

    • 2 mol/s
    • 0 mol/s
    • 8 mol/s
    • 4 mol/s

  7. At equilibrium, the amounts of reactants and products are:

    • Zero
    • Steadily decreasing
    • Steadily increasing
    • Constant

  8. What does a constant colour in a sealed reversible reaction mixture indicate?

    • Products used up
    • Catalyst exhausted
    • Reaction stopped
    • Equilibrium reached

  9. Which quantities become constant once a reversible reaction reaches equilibrium?

    • Masses
    • Volumes
    • Pressure
    • Concentrations

  10. Is a system at equilibrium if the forward rate exceeds the reverse rate?

    • No
    • Yes
    • Only if cooled
    • Only if heated

  11. If forward and reverse rates are both 2.0 mol/s, is the system at equilibrium?

    • Depends on volume
    • No
    • Yes
    • Only temporarily

  12. What type of apparatus is required to study chemical equilibrium?

    • Closed apparatus
    • Open beaker
    • Glass funnel
    • Porous crucible

  13. What remains constant for all reactants and products once a system reaches equilibrium?

    • Temperature
    • Volume
    • Concentration
    • Pressure

  14. What happens at the microscopic level in a closed vessel at equilibrium?

    • Reactions continue
    • Only products form
    • Only reactants form
    • All motion stops

  15. What does the term equilibrium position describe in a chemical system?

    • Reaction rate
    • Relative amounts
    • Total pressure
    • Activation energy

  16. Which factor does not alter the position of equilibrium?

    • Changing temperature
    • Changing pressure
    • Adding a catalyst
    • Changing concentration

  17. In a closed system at equilibrium observed over time, what remains unchanged?

    • Forward rate
    • Molecule motion
    • Collision frequency
    • Overall composition

  18. How can a closed system at equilibrium be disturbed?

    • Changing conditions
    • Adding catalyst
    • Sealing container
    • Constant temperature

  19. Which term describes the relative amounts of reactants and products in an equilibrium system?

    • Rate
    • Volume
    • Pressure
    • Position

  20. How do the rates of the forward and reverse reactions compare at equilibrium?

    • Zero
    • Equal
    • Faster forwards
    • Faster backwards

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