What is meant by the amount of a substance?

The amount of substance v is determined by the number of structural units (molecules, atoms, ions) that are in it.

For comparison, we took the number of atoms in 0.012 kg of the carbon isotope Na = 6 * 10 ^ 23.

v = N / Na, where N is the number of molecules in a given substance.

The unit for measuring the amount of substance v is the mole.

1 mole this is the amount of substance in which there are 6 * 10 ^ 23 structural units (molecules, atoms, ions).

The number of structural units 6 * 10 ^ 23 is called Avogadro’s number: Na = 6 * 10 ^ 23.