The mole (symbol: mol) is the SI base unit that measures an amount of substance. The mole is a counting unit. One mole contains Avogadro's number (approximately 6.02214) entities (atoms, molecules, elementary particles). The weight in grams of 1 mol of a substance is equal (in number) to the weight in AMUs of one atom/molecule of that substance. For instance, 1 mol of oxygen (O2) molecules weighs approximately 32 grams, whereas 1 molecule of oxygen would be equal to about 32 AMUs. A mole is much… (More on Millimole)