plumiMass spectrometry of organic compounds: OCR A‑Level Chemistry A questions
OCR A-Level Chemistry A past-paper questions on 4.2.4.3 Mass spectrometry of organic compounds, 2016–2025, with mark schemes and examiner’s reports where available.
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Open the full PDFYour answerQ6(a)(i)
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Open the full PDFYour answerQ20(a)
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All 21 questions on Mass spectrometry of organic compounds, as a list
- June 2025, Paper 2, Q11 (1 mark): Which molecule does not produce a mass spectrum containing a peak at m/z = 29? OH A O B O C O O D O OH Your answer [1]
- June 2025, AS Paper 1, Q19 (1 mark): In a mass spectrum, which alkene is likely to have a fragment ion at m / z = 29? A H2C=CHCH=CH2 B H2C=C(CH3)2 C H3CCH=CHCH3 D H3CCH=CHCH2CH3 Your answer [1]
- June 2025, AS Paper 2, Q6(a)(i) (2 marks): Draw structures for the ions responsible for peak P and peak Q. ion responsible for peak P ion responsible for peak Q [2]
- June 2025, AS Paper 2, Q6(a)(ii) (1 mark): Explain why there is a small peak at m / z = 73 [1]
- June 2024, AS Paper 1, Q20 (1 mark): An alcohol CH3CH2CH(CH3)OH produces a mass spectrum. The mass spectrum contains a large fragment ion at m/z = 45. What is the possible identity of this fragment
- June 2023, Paper 2, Q10 (1 mark): Which ester is most likely to produce a mass spectrum with a fragment ion at m / z = 43? OH O A H3C C C O CH3 CH3 O B HO CH2 C O CH2CH2CH3 OH O C H3C CH CH2 C O
- June 2023, AS Paper 1, Q20 (1 mark): Pentan-2-ol and pentan-3-ol are structural isomers with the molecular formula C5H12O and Mr = 88. The isomers can be distinguished from the fragment ions in the
- June 2022, AS Paper 1, Q20 (1 mark): Which alcohol is likely to have fragment ions at m / z = 15, 29 and 43 in its mass spectrum? OH A B OH OH C OH D Your answer [1]
- November 2021, Paper 2, Q12 (1 mark): Which peak would be in the mass spectrum of propanal, CH3CH2CHO, but not in the mass spectrum of propanone, CH3COCH3? A m /z = 15 B m /z = 29 C m /z = 43 D m /z
- November 2020, AS Paper 1, Q20 (1 mark): The mass spectrum of a carboxylic acid contains peaks at m /z = 29 and m /z = 102. Which compound could have produced the spectrum? O A OH OH B O OH C O OH D O
- June 2019, Paper 2, Q18(e)(ii) (2 marks): The mass spectrum of ester C is shown below. 100 Y 80 60 Relative intensity 40 Z 20 0 10 20 30 40 50 60 70 80 90 100 m / z Suggest possible structures for the s
- June 2019, AS Paper 1, Q18 (1 mark): Which compound is not likely to have a fragment ion at m / z = 43 in its mass spectrum? H H O A H C C C OH H H H O H C C B OH H H CH3 H H C C C OH C H H H H H H
- June 2019, AS Paper 2, Q3(b)(i) (1 mark): What information is given by the peak labelled X (m/z = 198)? [1]
- June 2019, AS Paper 2, Q3(b)(ii) (2 marks): Write the structural formulae of the ions responsible for the peaks labelled Y and Z. Y (m/z = 71) Z (m/z = 43) [2]
- June 2019, AS Paper 2, Q3(c)(ii) (2 marks): Suggest one similarity and one difference between the mass spectra of 1-iodopentane and 2-iodo-2-methylbutane. Similarity Difference [2]
- June 2018, Paper 2, Q12 (1 mark): The mass spectrum of (CH3)2CHCH2OH is shown below. 100 80 60 relative intensity 40 20 0 10 20 30 40 50 60 70 80 90 m /z Which ion is responsible for the peak wi
- June 2018, Paper 2, Q21(c)(ii) (3 marks): A general structure for esters J, L and M is shown below. O C R O HO Where ‘R’ is an alkyl group. Use the mass spectrometry results to deduce possible structure
- June 2018, AS Paper 1, Q20 (1 mark): Which alcohol is likely to have a fragment ion at m / z = 31 in its mass spectrum? A CH3CH2CH(OH)CH3 B CH3CH2CH2C(OH)(CH3)2 C CH3CH(OH)CH2CH2CH3 D (CH3)2CHCH2OH
- June 2017, Paper 2, Q20(a) (3 marks): The percentage composition and mass spectrum of the compound are shown below. Percentage composition by mass: C, 70.58%; H, 5.92%; O, 23.50%. Mass spectrum 100
- June 2017, AS Paper 1, Q20 (1 mark): Which alcohol is not likely to have a fragment ion at m / z = 43 in its mass spectrum? A CH3CH2CH(OH)CH3 B CH3CH2CH2CH2OH C CH3CH(OH)CH2CH2CH3 D (CH3)2CHCH2OH Y
- June 2017, AS Paper 2, Q4(b)(ii) (2 marks): The mass spectrum of alcohol C is shown below. Item removed due to third party copyright restrictions. Write structural formulae for the ions responsible for pe
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