The Mole

A mole is the amount of pure substance containing the same number of chemical units as there are atoms in exactly 12 grams of carbon-12 (i.e., 6.023 X 10²³). This allows us to count atoms, molecules and ions and therefore, allows us to be to use the correct amounts for a reaction. Remember that a balanced equation equation is a ratio in terms of moles so that the number of atoms on the left hand side of the equation is the same as the right hand side. In a reaction the atoms are not created or destroyed, they are just rearranged, old bonds are broken and new ones made.