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IB Chemistry HL 3.2.8 Hl Mass Spectrometry Questions

Use real exam mass spectra to identify molecular ions, assign fragment formulas and infer structural features from supplied m/z data.

Syllabus
First assessment 2025
Course
Chemistry HL
Level
HL

Exam points

  • Use the molecular-ion peak or isotope pattern to determine relative molecular mass, molecular-ion formula or isotope composition.
  • Assign formulas or structures to supplied fragment peaks using m/z values and the allowed fragmentation evidence.
  • Use a set of molecular-ion and fragment peaks to distinguish compounds or infer structural features consistent with the spectrum.

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Study 3.2.8 (HL)—Mass spectrometry conceptsOpen the corresponding Concept lesson for explanations, examples and exam connections.

IB Chemistry HL 3.2.8 Hl Mass Spectrometry Questions question 1

[Maximum number: 2]

Urea, (H2 N)2CO\left(\mathrm{H}_{2} \mathrm{~N}\right)_{2} \mathrm{CO}, is excreted by mammals and can be used as a fertilizer.

The mass spectrum of urea is shown below.

Figure for Question IB Chemistry HL 3.2.8 Hl Mass Spectrometry Questions question 1 — IB Chemistry HL

Reference Database Number 69, Eds. P.J. Linstrom and W.G. Mallard, National Institute of Standards and Technology, Gaithersburg MD, 20899, doi:10.18434/T4D303, (retrieved May 31, 2018).]

Identify the species responsible for the peaks at m / z=60 and 44 .

60:

44:

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