What is a mole

A mole is a unit of 'amount of stuff' and is equal to 6.022x10²³. It is such a big number because we use the mole to describe how many atoms we have of something, so instead of saying "I have 6.022x10²³ atoms of carbon" you can say "I have 1 mol of carbon". A reminder that mole is a unit of stuff not weight so 1 mole of iron will weigh more that 1 mole of carbon as the individual iron atoms that make up 1 mole of iron is heavier than a carbon atom.