Mole

From HvWiki

A mole (symbol: mol) is an arbitrary unit of measurement for mass similar to a dozen or a couple in the sense that it does not itself specify the exact mass in question. Instead, it is usually combined with an atom or molecule to represent how much mass it is referring to. One Mol of a specified atom is equivalent to the atom's atomic mass in grams. Moles can also be added together to represent molecules.

For example: the atomic weight of hydrogen is 1.0079 AMU So if you needed 1 Mol of Hydrogen, you would need 1.0079 grams. 2 Mols of hydrogen would be 2.0158 grams and so on. Oxygen has a weight of 15.99994 AMU, so if you wanted to find 1 Mol of water (H2O) You would combine 2 Mols of hydrogen with 1 Mol of oxygen (2.0158+15.99994) = 18.01574 grams.