Lesson 2.1.3

2.1.3 Amount of substance Quiz: OCR Chemistry, Unit 1

20 questions

Written by Revision Ninja · Last reviewed 11 October 2026

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Lesson 2.1.3, Amount of substance: 20 multiple choice questions for the OCR Chemistry (H432), Unit 1: Foundations in chemistry, written with Revision Ninja.

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The 20 questions

  1. What is the value of the Avogadro constant to three significant figures?

    • 1.60 × 10^-19
    • 6.02 × 10^22
    • 6.02 × 10^23
    • 3.00 × 10^8

  2. What is the molar gas volume at room temperature and pressure (RTP)?

    • 24.0 cm3 mol-1
    • 0.0821 dm3 mol-1
    • 24.0 dm3 mol-1
    • 22.4 dm3 mol-1

  3. What are the units of molar mass?

    • mol dm-3
    • g mol-1
    • mol g-1
    • g dm-3

  4. What is the empirical formula of glucose, C6H12O6?

    • C2H4O2
    • C3H6O3
    • C6H12O6
    • CH2O

  5. Which term means the simplest whole-number ratio of atoms of each element present?

    • Molecular formula
    • Empirical formula
    • Structural formula
    • General formula

  6. What term describes water molecules bound inside a hydrated salt crystal lattice?

    • Solvation water
    • Water of solution
    • Absorbed water
    • Water of crystallisation

  7. What is the mass of 0.5 mol of NaCl? (Mr = 58.5)

    • 29.25 g
    • 58.5 g
    • 117 g
    • 11.7 g

  8. How many moles are there in 4.00 g of NaOH? (Mr = 40.0)

    • 0.100 mol
    • 0.0100 mol
    • 4.00 mol
    • 0.400 mol

  9. What volume does 0.250 mol of nitrogen gas occupy at RTP?

    • 0.250 dm3
    • 9.60 dm3
    • 96.0 dm3
    • 6.00 dm3

  10. What volume does 1.00 mol of an ideal gas occupy at 298 K and 101 kPa? (R = 8.31 J K-1 mol-1)

    • 2450 dm3
    • 24.5 cm3
    • 0.0245 dm3
    • 24.5 dm3

  11. 2.00 g of NaOH is dissolved to make 250 cm3 of solution. What is the concentration in mol dm-3? (Mr = 40.0)

    • 0.0500 mol dm-3
    • 0.800 mol dm-3
    • 8.00 mol dm-3
    • 0.200 mol dm-3

  12. What mass of magnesium chloride, MgCl2 (Mr = 95.3), forms from 5.00 g of Mg (Ar = 24.3) reacting with excess HCl?

    • 5.00 g
    • 39.2 g
    • 9.80 g
    • 19.6 g

  13. A reaction has a theoretical yield of 12.5 g and an actual yield of 9.80 g. What is the percentage yield?

    • 56.0%
    • 21.6%
    • 127%
    • 78.4%

  14. What is the atom economy of C2H4 + H2O → C2H5OH? (Mr: C2H4 = 28, H2O = 18, C2H5OH = 46)

    • 100%
    • 75%
    • 128%
    • 50%

  15. Elemental analysis gives 40.0% C, 6.7% H and 53.3% O by mass. What is the empirical formula?

    • C2H4O2
    • CH2O
    • CHO
    • C3H6O3

  16. The empirical formula is CH2O and the Mr is 180. What is the molecular formula? (C = 12, H = 1, O = 16)

    • C2H4O2
    • C6H12O6
    • CH2O
    • C9H18O9

  17. When 6.25 g of hydrated copper(II) sulfate is heated, 4.00 g of anhydrous CuSO4 (Mr = 159.5) remains. Which formula describes the hydrate?

    • CuSO4.7H2O
    • CuSO4.4H2O
    • CuSO4.3H2O
    • CuSO4.5H2O

  18. 2.00 g of H2 reacts with 8.00 g of O2 to form water. What mass of water is formed?

    • 9.00 g
    • 18.0 g
    • 4.50 g
    • 16.0 g

  19. Which of these 1.00 g gas samples occupies the largest volume at RTP?

    • Oxygen, O2
    • Methane, CH4
    • Hydrogen, H2
    • Helium, He

  20. A 1.00 dm3 container holds 0.0500 mol of gas at 300 K. What is the pressure? (R = 8.31 J K-1 mol-1)

    • 1250 kPa
    • 12.5 kPa
    • 125 kPa
    • 1.25 kPa

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