Lesson 5.3.2.4

5.3.2.4 Limiting reactants (HT only) Quiz: AQA Combined Science, Unit 10

20 questions

Written by Revision Ninja · Last reviewed 11 October 2026

In partnership with Revision Ninja

Lesson 5.3.2.4, Limiting reactants (HT only): 20 multiple choice questions for the AQA GCSE Combined Science (8464), Unit 10: Quantitative chemistry, written with Revision Ninja.

Host it live on the board and students join with a game code on their own devices, or revise alone with Free Play. The answers are revealed in the game.

Host this setFree Play

The 20 questions

  1. What is the reactant that is completely used up first in a reaction called?

    • Product
    • Limiting reactant
    • Excess reactant
    • Catalyst

  2. Why is one reactant often added in excess during a chemical reaction?

    • Ensure complete reaction
    • Increase the temperature
    • Prevent gas formation
    • Speed up the catalyst

  3. What determines the maximum amount of product formed in a chemical reaction?

    • Reaction vessel size
    • Limiting reactant
    • Total volume
    • Excess reactant

  4. Reaction 2Mg + O2 -> 2MgO uses 0.2 mol Mg and 0.2 mol O2. What is limiting?

    • Oxygen
    • Both reactants
    • Magnesium oxide
    • Magnesium

  5. Using the same reaction, 0.2 mol of Mg and 0.2 mol of O2, how many moles of MgO form?

    • 0.2 mol
    • 0.1 mol
    • 0.05 mol
    • 0.4 mol

  6. In H2 + Cl2 -> 2HCl, 0.5 mol of H2 reacts with 0.3 mol of Cl2. How many moles of HCl form?

    • 0.3 mol
    • 0.5 mol
    • 0.6 mol
    • 1.0 mol

  7. In Mg + 2HCl -> MgCl2 + H2, if 0.1 mol of Mg reacts with 0.15 mol of HCl, which is limiting?

    • Magnesium chloride
    • Hydrogen
    • Hydrochloric acid
    • Magnesium

  8. In the same reaction, 0.1 mol of Mg is mixed with 0.15 mol of HCl. How many moles of MgCl2 form?

    • 0.075 mol
    • 0.2 mol
    • 0.15 mol
    • 0.1 mol

  9. 3 mol of H2 reacts with 1 mol of O2 in 2H2 + O2 -> 2H2O. What is left over at the end?

    • 2 mol of H2O
    • 1 mol of O2
    • 1 mol of H2
    • 3 mol of H2

  10. 14 g of nitrogen (0.5 mol) reacts with 9 g of hydrogen (4.5 mol) in N2 + 3H2 -> 2NH3. What mass of ammonia (Mr 17) forms?

    • 17 g
    • 51 g
    • 8.5 g
    • 34 g

  11. 12 g of magnesium reacts with 12 g of oxygen in 2Mg + O2 -> 2MgO. Which reactant is limiting? (Mg = 24, O2 = 32)

    • Oxygen
    • Both reactants equally
    • Neither reactant
    • Magnesium

  12. In 2H2 + O2 -> 2H2O, if 4 g of hydrogen reacts with 40 g of oxygen, which reactant is limiting?

    • Hydrogen
    • Oxygen
    • Water
    • Steam

  13. What mass of water forms from 4 g of hydrogen and 40 g of oxygen in 2H2 + O2 -> 2H2O? (H2O = 18)

    • 54 g
    • 72 g
    • 36 g
    • 18 g

  14. 3 mol of N2 reacts with 6 mol of H2 in N2 + 3H2 -> 2NH3. How many moles of NH3 form?

    • 3 mol
    • 2 mol
    • 4 mol
    • 6 mol

  15. In the same reaction, 3 mol of N2 reacts with 6 mol of H2. How many moles of N2 are left over?

    • 1 mol
    • 3 mol
    • 2 mol
    • 0 mol

  16. What happens to the mass of product when you increase the limiting reactant?

    • Stays constant
    • Increases
    • Decreases
    • Halves

  17. Which reactant is limiting when 10 g of calcium carbonate reacts with 0.15 mol of hydrochloric acid?

    • Carbon dioxide
    • Calcium carbonate
    • Hydrochloric acid
    • Calcium chloride

  18. In the same reaction with 0.1 mol of CaCO3 and 0.15 mol of HCl, how many moles of CO2 form?

    • 0.1 mol
    • 0.15 mol
    • 0.075 mol
    • 0.05 mol

  19. Which reactant is limiting when 5.4 g of aluminium reacts with 0.45 mol of chlorine?

    • Both
    • Aluminium
    • Aluminium chloride
    • Chlorine

  20. In the same reaction with 0.2 mol of Al and 0.45 mol of Cl2, how many moles of AlCl3 form?

    • 0.45 mol
    • 0.1 mol
    • 0.2 mol
    • 0.3 mol

All AQA Combined Science quizzes