A sorites paradox in the conventional definition of amount of substance

Abstract

Abstract. The conventional definition of amount of substance n is as a quantity proportional to number of entities N. This implies that n is discrete for small N while n is considered to be continuous at the macroscopic scale, leading to a sorites paradox. A practical criterion is proposed for distinguishing between amount of substance and number of entities, and the implications for the conventional definition of amount of substance are discussed.

A critical review of the proposed definitions of fundamental chemical quantities and their impact on chemical communities (IUPAC Technical Report)

“…For example, in the article by Wheatley [84], a widespread divergence of opinion about the nature of the Avogadro constant is shown: some believe it is a number whereas others believe it is a quantity with a dimension of N −1 . Peculiar and hard-to-understand to many is also the observation that the Avogadro constant cannot be understood without the mole and yet the proposed definition of the mole rests entirely on the Avogadro constant.…”

“…Consequently, Wheatley finds that the unchanged method to realize the mole demonstrates no practical reason to redefine this unit [84]. He argues that new definitions should only be prompted by better ability to realize the units, which is certainly not the case for the mole.…”

a Critical Review of the Proposed Definitions of Fundamental Chemical Quantities and Their Impact on Chemical Communities (IUPAC Technical Report)

“…In many articles we read that the key concepts used by chemists are not well understood. For example, in the article by Wheatley [84], a widespread divergence of opinion about the nature of the Avogadro constant is shown: some believe it is a number whereas others believe it is a quantity with a dimension of N −1 . Peculiar and hard-to-understand to many is also the observation that the Avogadro constant cannot be understood without the mole and yet the proposed definition of the mole rests entirely on the Avogadro constant.…”

“…The proposed new SI introduces a change in the definition of the mole from a mass basis to a number basis but the practical realization of the mole in a routine laboratory work will still be performed on a mass basis. Consequently, Wheatley finds that the unchanged method to realize the mole demonstrates no practical reason to redefine this unit [84]. He argues that new definitions should only be prompted by better ability to realize the units, which is certainly not the case for the mole.…”

The prospect of the dalton in the new SI: an educator’s point of view

“…[9], claim that mole is a macroscopic unit, whereas others, for example [10], emphasize its link with the number of entities on the atomic scale. In the twenty-first century, it is trivial to say that the description of a macroscopic system (consisting of atoms or molecules) can be done, in a macroscopic or in a microscopic way, by the same quantity.…”