The mole in quantitative chemistry

The purpose is to show how the mole concept mn he applied more consistently and efficiently to all aspects of qnant,it.ative chemistry than conven-...
1 downloads 0 Views 3MB Size
George Novello Copley

I

-. I@

Mole in Quantitative Chemistry

The purpose is to show how the mole concept mn he applied more consistently and efficiently to all aspects of qnant,it.ative chemistry than conventional approaches that dispense with this concept. Part,ly to limit the field t,o he covered, but mainly to show-to what extent such well-known laws as those of Dulong and Pet,it and of Faraday are independent of the molecular hypot,hesis of Avogadro, t,his will he done with almost no reference to the relationship of the mole t,o t,he molecule, which is discussed elsewhere (1). The mole is here regarded as a unit quantity (2), in terms of which quantitative chemistry receives it,s simplest expression, and the conventions of quantity calculus (3) are accordingly employed. Some longeshblished terms will he shown to be either misnomers [like "atomic weight1'(2)] or superfluous [like "normality" (b)]. I t is proposed that such terms should be abolished from the teaching of chemistry and replaced by t,he molar treat,ment to be described, but supplement.ed by molecular interpretations outside the scope of t,his essay. Origin of the Mole Concept

'

The mole concept originated in the study of gases

(6). The molar [or mol (I)] amount, n, of any gas, Based upon a talk entitled "Gulliver in the Land Without Atomic Weights," given an Mnrch 25, 1961, at a Short Course for Teachers of Ch~mistry,xt Bmdford Institute of Technology, England.

which may he a mixture, is given by:

The unit in which n is measured is the mole. Suppose that (1) is used t,o measure the molar amounts, n, (i = 1, 2, ...), of gases, which are then mixed, and that the molar amount of their mixture is then determined, again using (1). Then it is found that,:

=En