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Halogenated compounds are particularly easy to identify by their mass spectra be

ID: 978969 • Letter: H

Question

Halogenated compounds are particularly easy to identify by their mass spectra because chlorine and bromine occur naturally as mixtures of two abundant isotopes.

Chlorine occurs as 35Cl (75.8%) and 37Cl (24.2%);

Bromine occurs as 79Br (50.7%) and 81Br (49.3%);

Boron compounds also stand out owing to the two isotopes 10B (19.9%) and 11B (80.1%).

For the compound Bromomethane, CH3Br:

At what masses do the molecular ions occur? _____________
(List in order of increasing mass separated by commas, e.g. 120,122.)

What are the percentages of each molecular ion? ____________
(List to nearest 1% in order of increasing mass separated by commas, e.g. 55,45.)

Explanation / Answer

Molecular ion peaks occured at the masses of 94, 96

Percentages of each molecular ion peak = 50.7 , 49.3