clarity with amount of substance

G9. DELIVERING A LACK OF CLARITY BY USE OF WRONG TERMINOLOGY

While the quantity ‘amount of substance' or ‘chemical amount' (‘Stoffmenge' in German) had been
used by chemists for a long time without a proper name, formerly, in the English-speaking world, it was more commonly referred to as 'number of moles', 'Molzahl' in German.

The intention was that this practice should have been discontinued around 1970 following updated CGPM / IUPAC / IUPAP recommendations and the establishment of ‘amount of substance’ as an S.I. base physical quantity along with its unit ‘mole’. At 2023, that was over 50 years' ago..

Just as It is quite wrong to use ‘number of metres' as a synonym for ‘length', it is equally wrong to use ‘number of moles' as a synonym for ‘amount of substance'.

Any pure number, by definition, of course, has NO UNITS. In fact, the ‘number of moles’ is given by the expression n / mol in the same way that ‘number of grams’ – were it required – would be given by m / g. These can be handy expressions for labelling the axes on a graph or column headings in data tables.

establishing entities

no. of entities & mass