A novel classification of concentration units

Abstract

Concentration units can be a source of confusion for students. This article presents a treatment on this topic that may help students understand the differences between these units.

Ternary and quaternary composition diagrams: an overview of the subject

“…The discussions in this paper have been presented in terms of mole fraction; they could be presented equally well in terms of weight fraction by letting Xi represent weight fraction, and ml represent the mass of each component i, in eqns. (1) (3) and (5) (31). It should be noted that straight lines on a weight fraction diagram are transformed into straight lines on a mole fraction diagram, etc.…”

“…In other cases it may be advantageous to use a non-isosceles right triangle, for example when expressing concentrations in terms of weight molarity (1,31) or if one wishes to expand one axis relative to another (23,24,45). The right triangular representation was first introduced by Roozeboom (39, 46).…”

“…Thus, the composition of a binary system can be depicted by means of a line extending from xa = 0 to Xa = 1 (or from xb = 1 to Xb = 0). All compositions of a system, prepared by mixing A and B, are uniquely represented by specific points on this line.…”

“…This, of course, corresponds to the composition axis of binary phase diagrams, such as boiling point diagrams (4, 5). In general, for an n-component system, £ Xi = 1 (2)…”

“…(2) with n = 3. A more general form of this condition was presented in a previous paper (1). Phase diagrams constitute the single largest application of triangular coordinates (4)(5)(6)(7)(8)(11)(12)(13)(14)18,19,(21)(22)(23)(24).…”