What is a Mole?

The mole (symbol: mol) is the SI base unit that measures an amount of substance. One mole contains Avogadro's number (approximately 6.022*10^23) entities. A mole is much like "a dozen" in that both units can describe any set of elementary objects, although the mole's use is usually limited to measurement of subatomic, atomic, and molecular structures. This is all due to the fact that a mole represents an exceedingly large number of entities.