Mole, in chemistry, a quantity of particles equal to Avogadro's number, or 6.02252 × 1023. One mole of a given compound is that number of molecules of the compound. The gram-atomic weight of an element is the weight, in grams, of a mole of that element. The gram-molecular weight of a compound is the weight in grams of a mole of molecules of that compound.
See also: Chemistry.