Mass spectrometryEdexcel International A Level Chemistry: Mind map

Exam questions on Mass spectrometry

1. A forensic laboratory analyses a metal sample using a mass spectrometer. The sample gives two peaks: one at m/z 63 with a relative abundance of 69.2 % and one at m/z 65 with a relative abundance of 30.8 %. All the ions have a charge of 1+.
   Explain why the inside of a mass spectrometer is kept under a high vacuum.2 marks
2. Boron has two isotopes, ¹⁰B and ¹¹B. A mass spectrum of a boron sample gives a relative atomic mass of 10.8.
   A second sample of boron contains a greater proportion of ¹⁰B than the first. State and explain how its relative atomic mass compares with 10.8.2 marks
3. Chlorine consists of two isotopes, ³⁵Cl (75.0 %) and ³⁷Cl (25.0 %). A sample of chlorine gas, Cl₂, is analysed in a mass spectrometer, and molecular ions, Cl₂⁺, are detected.
   Identify the molecular ions responsible for the peaks at m/z 70, 72 and 74.3 marks