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2000
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In the Classroom
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No, the Molecular Mass of Bromobenzene Is Not 157 amu: An Exercise in Mass Spectrometry and Isotopes for Early General Chemistry
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Steven M. Schildcrout
Department of Chemistry, Youngstown State University, Youngstown, OH 44555-3663
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November 2000
Vol. 77 No. 11
p. 1433
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| Abstract |
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Early in the general chemistry course, after they are introduced to the concepts of atomic weight, molecular mass, isotopes, ions, chemical formulas, and chemical equations, our students do a cooperative, guided-inquiry exercise involving interpretation of the mass spectrum of bromobenzene. This exercise illustrates, refines, reinforces, and extends these concepts while the students learn some chemical principles of electron-ionization mass spectrometry. Even with no background in bonding and structure, they can successfully interpret the output of a modern research instrument. They learn to identify an isotope pattern, assign chemical formulas to ions giving mass spectral peaks, calculate an average atomic weight (for bromine) from measured isotopic abundances, and write balanced equations for ion fragmentation reactions.
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| Supplement |
An abstract, student worksheets, and a tabulation of the data corresponding to Fig. 1 are available.
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 Contents |
JCE2000p1433W.doc (Microsoft Word 98)
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| Download |
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| More Information |
Citation |
Schildcrout, Steven M. J. Chem. Educ. 2000 77 1433.
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Keywords |
Bromine; General Chemistry; Isotopes; Mass Spectrometry
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History |
Created:
Last Updated: |
October 6, 2000
August 31, 2005
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| Home > JCE Print > Journal of Chemical Education > Issues >
2000
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November
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1433
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