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Formulae, equations and amount of substance: OCR A‑Level Chemistry B questions

Every OCR A-Level Chemistry B exam question on DM Formulae, equations and amount of substance (specification points DM(a)), 2016–2025, with its mark scheme and examiner’s report.

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2,049 questions

  1. Q2(e)(i)

    June 2024 · Paper 2

    4 marksDM Formulae, equations and amount of substance
    The whole paper ↗
    June 2024 Paper 2, question 2(e)(i): Calculate the mass of iron (in mg) in one iron tablet. mass of iron in one tablet = mg [4]

  2. Q2(e)(ii)

    June 2024 · Paper 2

    3 marksDM Formulae, equations and amount of substance
    The whole paper ↗
    June 2024 Paper 2, question 2(e)(ii): The student uses a volumetric pipette to transfer 25.0 cm3 of the acidic solution to a conical flask. Give the practical details of the student’s next steps to

  3. Q34(c)

    June 2023 · Paper 1

    6 marksDM Formulae, equations and amount of substance
    The whole paper ↗
    June 2023 Paper 1, question 34(c): Electrode potentials are used to investigate redox reactions. Standard electrode potentials for a range of redox half-cells are shown in Table 34.1. Table 34.1

  4. Q14

    November 2021 · Paper 1

    1 markDM Formulae, equations and amount of substance
    The whole paper ↗
    November 2021 Paper 1, question 14: What volume of 0.02 mol dm–3 potassium manganate(VII) solution is needed to oxidise 25.0 cm3 of 0.15 mol dm–3 FeSO4? – + 5Fe2+ + 8H+ Mn2+ + 5Fe3+ + 4H2O The equ

  5. Q16

    November 2020 · Paper 1

    1 markDM Formulae, equations and amount of substance
    The whole paper ↗
    November 2020 Paper 1, question 16: Manganate(VII) and iron(II) ions react as shown. − + 5Fe2+ + 8H+ Mn2+ + 5Fe3+ + 4H2O MnO4 What volume, in cm3, of 0.10 mol dm−3 Fe2+ will react with 25 cm3 of 0

  6. Q4(a)

    June 2019 · Paper 3

    1 markDM Formulae, equations and amount of substance
    The whole paper ↗
    June 2019 Paper 3, question 4(a): Suggest why the titre values in Table 2 increase from sample 1 to sample 4. [1]

  7. Q4(b)(i)

    June 2019 · Paper 3

    1 markDM Formulae, equations and amount of substance
    The whole paper ↗
    June 2019 Paper 3, question 4(b)(i): Show how the students calculated the value of 8.00 cm3 as their titre for the calculation. [1]

  8. Q4(b)(ii)

    June 2019 · Paper 3

    4 marksDM Formulae, equations and amount of substance
    The whole paper ↗
    June 2019 Paper 3, question 4(b)(ii): Foods ‘high’ in iron usually contain more than 4 mg of iron per 100 g of foodstuff. A student states that the data in Tables 1 and 2 show that spinach is ‘high

  9. Q4(c)(i)

    June 2019 · Paper 3

    1 markDM Formulae, equations and amount of substance
    The whole paper ↗
    June 2019 Paper 3, question 4(c)(i): Calculate the percentage uncertainty in titre 1 for sample 4. percentage uncertainty = % [1]

  10. Q4(c)(ii)

    June 2019 · Paper 3

    2 marksDM Formulae, equations and amount of substance
    The whole paper ↗
    June 2019 Paper 3, question 4(c)(ii): The students want to reduce the percentage uncertainty in the titre values, while using the same equipment. Suggest two ways in which they can do this. 1 2 [2]

  11. Q35(b)

    June 2018 · Paper 1

    3 marksDM Formulae, equations and amount of substance
    The whole paper ↗
    June 2018 Paper 1, question 35(b): The chemists then titrated 10.0 cm3 portions of their solutions with a solution of 0.200 mol dm–3 potassium manganate(VII). – ions oxidise the Fe2+ to Fe3+ and

  12. Q4(d)(i)

    June 2017 · Paper 2

    6 marksDM Formulae, equations and amount of substance
    The whole paper ↗
    June 2017 Paper 2, question 4(d)(i): Some students add acid and 20.0 cm3 of 0.200 mol dm–3 Cr2O7 2– to 25.0 cm3 of a ‘low-alcohol’ beer. They add excess iodide ions and find that the iodine produce

  13. Q4(d)(ii)

    June 2017 · Paper 2

    1 markDM Formulae, equations and amount of substance
    The whole paper ↗
    June 2017 Paper 2, question 4(d)(ii): Suggest one assumption the students have to make when giving their result. [1]
All 13 questions on Formulae, equations and amount of substance, as a list
  1. June 2024, Paper 2, Q2(e)(i) (4 marks): Calculate the mass of iron (in mg) in one iron tablet. mass of iron in one tablet = mg [4]
  2. June 2024, Paper 2, Q2(e)(ii) (3 marks): The student uses a volumetric pipette to transfer 25.0 cm3 of the acidic solution to a conical flask. Give the practical details of the student’s next steps to
  3. June 2023, Paper 1, Q34(c) (6 marks): Electrode potentials are used to investigate redox reactions. Standard electrode potentials for a range of redox half-cells are shown in Table 34.1. Table 34.1
  4. November 2021, Paper 1, Q14 (1 mark): What volume of 0.02 mol dm–3 potassium manganate(VII) solution is needed to oxidise 25.0 cm3 of 0.15 mol dm–3 FeSO4? – + 5Fe2+ + 8H+ Mn2+ + 5Fe3+ + 4H2O The equ
  5. November 2020, Paper 1, Q16 (1 mark): Manganate(VII) and iron(II) ions react as shown. − + 5Fe2+ + 8H+ Mn2+ + 5Fe3+ + 4H2O MnO4 What volume, in cm3, of 0.10 mol dm−3 Fe2+ will react with 25 cm3 of 0
  6. June 2019, Paper 3, Q4(a) (1 mark): Suggest why the titre values in Table 2 increase from sample 1 to sample 4. [1]
  7. June 2019, Paper 3, Q4(b)(i) (1 mark): Show how the students calculated the value of 8.00 cm3 as their titre for the calculation. [1]
  8. June 2019, Paper 3, Q4(b)(ii) (4 marks): Foods ‘high’ in iron usually contain more than 4 mg of iron per 100 g of foodstuff. A student states that the data in Tables 1 and 2 show that spinach is ‘high
  9. June 2019, Paper 3, Q4(c)(i) (1 mark): Calculate the percentage uncertainty in titre 1 for sample 4. percentage uncertainty = % [1]
  10. June 2019, Paper 3, Q4(c)(ii) (2 marks): The students want to reduce the percentage uncertainty in the titre values, while using the same equipment. Suggest two ways in which they can do this. 1 2 [2]
  11. June 2018, Paper 1, Q35(b) (3 marks): The chemists then titrated 10.0 cm3 portions of their solutions with a solution of 0.200 mol dm–3 potassium manganate(VII). – ions oxidise the Fe2+ to Fe3+ and
  12. June 2017, Paper 2, Q4(d)(i) (6 marks): Some students add acid and 20.0 cm3 of 0.200 mol dm–3 Cr2O7 2– to 25.0 cm3 of a ‘low-alcohol’ beer. They add excess iodide ions and find that the iodine produce
  13. June 2017, Paper 2, Q4(d)(ii) (1 mark): Suggest one assumption the students have to make when giving their result. [1]

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