plumiFormulae, equations and amount of substance: OCR A‑Level Chemistry B questions
Every OCR A-Level Chemistry B exam question on ES Formulae, equations and amount of substance (specification points ES(a)), 2016–2025, with its mark scheme and examiner’s report.
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Q21(a)
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Q23(b)
The whole paper ↗![June 2024 AS Paper 1, question 23(b): What is the atom economy of the Cativa process for producing ethanoic acid? atom economy = % [1]](https://pub-e8a9dbab8e2a4d089f52b2a45e0d0b50.r2.dev/bank/h03301-jun24-23-b-qp.webp?v=3)
Q3(c)(ii)
The whole paper ↗![June 2023 AS Paper 2, question 3(c)(ii): Calculate the atom economy of this preparation of aspirin. atom economy = % [1]](https://pub-e8a9dbab8e2a4d089f52b2a45e0d0b50.r2.dev/bank/h03302-jun23-03-cii-qp.webp?v=3)
Q4(g)(i)
The whole paper ↗![November 2020 Paper 2, question 4(g)(i): Use calculated atom economies to suggest, with a reason, which reaction is used more. [2]](https://pub-e8a9dbab8e2a4d089f52b2a45e0d0b50.r2.dev/bank/h43302-nov20-04-gi-qp.webp?v=3)
![June 2017 Paper 1, question 33(e)(i): Calculate the atom economy of the reaction in equation 33.1 when making hydrogen. atom economy = % [1]](https://pub-e8a9dbab8e2a4d089f52b2a45e0d0b50.r2.dev/bank/h43301-jun17-33-ei-qp.webp?v=3)
Q23(b)(iii)
The whole paper ↗![June 2016 AS Paper 1, question 23(b)(iii): State and explain the atom economy of the reaction in (ii). [1]](https://pub-e8a9dbab8e2a4d089f52b2a45e0d0b50.r2.dev/bank/h03301-jun16-23-biii-qp.webp?v=3)
Q3(a)(iii)
The whole paper ↗![June 2016 AS Paper 2, question 3(a)(iii): Calculate the atom economy for the production of aspirin. atom economy = % [2]](https://pub-e8a9dbab8e2a4d089f52b2a45e0d0b50.r2.dev/bank/h03302-jun16-03-aiii-qp.webp?v=3)
All 16 questions on Formulae, equations and amount of substance, as a list
- June 2025, AS Paper 1, Q21(a) (2 marks): This process is regarded as ‘green’ because water is the only co-product and the reaction has a high atom economy. Calculate the atom economy of the process. At
- June 2024, Paper 1, Q14 (1 mark): Which reaction has the smallest atom economy for the formation of the organic product? A C2H4 + HCl C2H5Cl B C2H4 + HBr C2H5Br C C2H6 + Cl 2 C2H5Cl + HCl D C2H6
- June 2024, AS Paper 1, Q23(b) (1 mark): What is the atom economy of the Cativa process for producing ethanoic acid? atom economy = % [1]
- June 2023, Paper 1, Q21 (1 mark): The following equations represent reactions for making hydrogen from water. Which reaction produces hydrogen with the greatest atom economy? A C + H2O H2 + CO B
- June 2023, AS Paper 1, Q10 (1 mark): Methane reacts with steam to form hydrogen: CH4(g) + 2H2O(g) CO2(g) + 4H2(g) What is the atom economy of this reaction for the formation of hydrogen? A 4.3% B 1
- June 2023, AS Paper 2, Q3(c)(ii) (1 mark): Calculate the atom economy of this preparation of aspirin. atom economy = % [1]
- June 2022, AS Paper 1, Q5 (1 mark): Which reaction has the largest atom economy for the formation of the organic product? A C2H4 + Br2 C2H4Br2 B C2H5Br + Br2 C2H4Br2 + HBr C C6H6 + Br2 C6H5Br + HB
- November 2021, Paper 1, Q17 (1 mark): 4.6 g of ethanol (C2H5OH, Mr = 46) are converted to ethanal. 2.0 g of ethanal (CH3CHO) are formed. What is correct? A The atom economy cannot be calculated from
- November 2021, AS Paper 1, Q3 (1 mark): Which expression is the definition of atom economy? amount (mol) of desired product A total amount (mol) of products × 100 mass of desired product B total mass
- November 2020, Paper 2, Q4(g)(i) (2 marks): Use calculated atom economies to suggest, with a reason, which reaction is used more. [2]
- November 2020, AS Paper 1, Q10 (1 mark): Which reaction has the lowest atom economy for making an ester? A Reacting butan-1-ol with butanoic acid. B Reacting ethanol with ethanoic acid. C Reacting meth
- June 2019, Paper 1, Q6 (1 mark): Aspirin is synthesised by the reaction below. O OH O OH O O O OH + O + O OH O Mr 138 Mr 102 What is the atom economy of this reaction for producing aspirin? A 2
- June 2017, Paper 1, Q33(e)(i) (1 mark): Calculate the atom economy of the reaction in equation 33.1 when making hydrogen. atom economy = % [1]
- June 2017, AS Paper 1, Q3 (1 mark): What is a correct measure of percentage atom economy? A mass of useful products × 100 / mass of reactants B amount of products × 100 / amount of reactants C Mr
- June 2016, AS Paper 1, Q23(b)(iii) (1 mark): State and explain the atom economy of the reaction in (ii). [1]
- June 2016, AS Paper 2, Q3(a)(iii) (2 marks): Calculate the atom economy for the production of aspirin. atom economy = % [2]
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