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CEJ Vol. 7, No. 2, ContentsChemical Education Journal (CEJ), Vol. 7, No. 2 /Registration No. 7-20/Received September 17, 2003.
Department of Physical Sciences, Prince George's Community College, Largo, Maryland 20774, USA
E-mail: rgross@pgcc.edu
Abstract
A sample of a compound that contains a few chlorine and bromine atoms in its molecular formula is composed of multiple sets of unit samples of molecules that replicate the molecular composition of the bulk sample. The number of molecules in a unit sample is stoichiometrically related to the number of bromine and chlorine atoms in the formula and contains unique molecules and duplicates of them or non-unique molecules. It is shown that the number of chlorine atoms in the formula is a function of the fraction of non-unique molecules in the unit sample. This relationship allows the number of chlorine atoms and hence the number of bromine atoms in the formula of an unknown compound to be calculated, because the molecular composition of a unit sample can be found from the molecular-ion peaks in the mass spectrum of the compound. Unit samples help instructors and students understand the nature of molecular compositions.
Abstract
Introduction
Results and Discussion
Conclusions
References