What is a mole?

 

A mole is simply a number, an amount of something. Like when people refer to a dozen of eggs they mean 12 eggs, when someone says a mole of atoms they mean 6.022 x 10²³ atoms. A mole is simply defined as ‘the amount of a substance containing 6.022 x 10²³ particles.’ 6.022 x 10²³ is 602,200,000,000,000,000,000,000 when written out in full – it’s a huge number! It is called Avogadro’s number after the man that calculated this. So you can literally have a mole of anything for example a mole of apples mean you have 6.022 x 10²³ apples!

The reason why we have the mole is so that chemists can do calculations. If you look at a periodic table, under the symbol for each element there is a number, for example for sodium that number is 22.990. This number is how much 1 mole of sodium weighs in grams so 1 mole of sodium weighs 22.990g. This is called the molar mass: ‘the mass in grams of 1 mole of atoms of a given element.’

So the key this to remember is a mole is just a number: 6.022 x 10²³. This is something which you will use in GCSE chemistry and even more if you decide to do A-Level chemistry!