Just like you can have one dozen eggs (12) or one ream of paper (500), a mole is a number used to measure things. The number associated with one mole is 6.02x10^23-which is a mind-blowingly large number. Specifically, moles are used in chemistry, and this is because moles reference huge quantities of tiny molecules and atoms. For example, in just a half-liter water bottle, you will find just over 25 moles of water molecules.