.
The Mole is "a unit of measure established to use
in counting particles in substances.
[Abbreviation of the unit
(mol)]
The mol is the the amount
of a substance that contains as many entities as there are in exactly 12
g of carbon-12.
1 mol of
something consists of 602.214.000.000.000.000.000.000
= 6.02214 x 1023 units of that substance"(S.S. Zumdahl). Of
course nobody can count this quantity.
But the amount of 1 mole can be
measured by a scale:
1 mol = 6,02x1023 water molecules weigh 18 g.
So 1 millimol = 6,02x1020 water molecules weigh 18 mg.
So each micro drop of water contains more than 1020 water molecules.
.