What is a mole and the calculations used to find the number of moles?

A mole in chemistry is a unit of amount. Similar to saying a dozen is 12, a mole is 6.022x10^23 atoms, conveniently called Avogadro's number. If we take one mole of carbon atoms, this is equal to a mass of 12.000g of carbon. One mole of any pure substance is equal to the relative atomic mass, found on the periodic table.This allows us to perform calculations to find the number of moles, using the definition above. The number of moles = the mass/relative atomic mass. If we have 12g of carbon, with relative atomic mass 12, dividing the 2, we get 1 mole. The number of moles can also be used in stoichiometry calculations and allow you to use ratios to work out unknown masses of either product or reactants.