Physical quantities usable for measuring the quantity:
m mass kg
n amount of substance mol
V volume m3
z count 1

Concentration-like physical quotient quantities built up on the base above

Example: oxygen-nitrogen gas mixture (O and N)

quantity equation quantity equation unit
wB mass fraction  mass ratio
jB volume fraction  volume ratio
xB amount-of-substance fraction rB amount-of-substance ratio
molecular fraction molecular ratio
range of the function 0-1   0-endless  

The mole ratio is equal to the molecule ratio because of the Avogadro's Law and the definition of the mole unit.

The "unit one" is under dispute at a commission of the Bureau Internationale des Poids et Measures & and doesn't seem usable for countable quantities.

ratio: quantity of one component divided by the other component (the solvent)
fraction: quantity of one component divided by the whole mixture

Notice that the unit "percent" can be undestood in eight different meanings and different values.

The number of millet divided by the number of the whole mixture (millet plus wheat) is not equal to its molecule ratio. I can not name it. Count ratio?

Quantities divided by the volume of the mixture (they are called concentration)

mass mass concentration
amount of substance amount-of-substance concentration
volume volume fraction volume fraction
number, entity, count molecular concentration

Oxygen content of the normal air (is it 21 percent, less or more?)

volume fraction jO 0.2093
mass fraction wO 0.232
amount-of-substance fraction xO 0.2117
amount-of-substance ratio (for nitrogen) rO 0.2178
mass concentration   rO 0.3

Created by JŠnos Zana