27. ISO 80000-9 — Physical chemistry and molecular physics
The seventh part specified in full is ISO 80000-9, Physical chemistry and molecular
physics. Every item — all of 9-1 … 9-49, sixty-two including every sub-suffixed item — is
catalogued: counting entities and the mole, the molar quantities, the concentrations and
fractions, the chemical potential and the activity ladder, the reaction and equilibrium
quantities, statistical mechanics, and the transport and electrochemical coefficients —
each carrying its exact source as data. Only citation locators are recorded; no normative
content from the licensed standard is reproduced. The defining mathematics of selected
remarks is specified in the sibling module Part9.DefiningRelations.
Physical chemistry is the home of the mole, and so the sharpest test in the series of
the Finkelstein–Whitehead scale-spanning reduction (the Scale-spanning units chapter,
requirement R13): the mole is a human-selected dimensionless count of entities, N_A of
them, so Dim.amountOfSubstance = 1, and every quantity per mole drops the mole. One
reduction reorganizes the whole part. Amount of substance joins the dimensionless family.
Molar mass is a mass, molar volume a volume, the amount-of-substance concentration a
number density, molality an inverse mass. The seven J/mol quantities collide on one
dimension; the three J/(mol·K) quantities on another.