Knowledge database: 3.4 Amount of substance

Amount of substance (n), as the name itself says, is a measure of the amount of a substance, with the mole being the unit of this physical quantity. One mole is equal to Avogadro's number of particles. That number in turn is equal to the number of atoms in 12 grams of carbon isotope C (A=12). Therefore, one mole of any substance has 6.0221415x10^23 particles.

Amount of substance can simply be calculated by taking the mass of a substance (m) and dividing it by the molar mass of that same substance (M). It can also be obtained by dividing the number of particles (N) by the Avogadro's constant (L) which is numerically equal to Avogadro's number, but it comes with the unit mol^-1.

Amount of substance is one of the most important physical quantities, not only in chemistry, but in general science, and therefore it is reasonably classified into the 7 basic physical quantities of the SI system.