Mole: GCSE Chemistry Definition

What is a mole?

In GCSE Chemistry, the mole is a unit used to measure the amount of a substance. A mole is defined as the amount of substance that contains 6.02 x 10²³ particles (atoms, molecules, ions or electrons). This number is known as the Avogadro Constant.

Mole calculations

The mole is essential for performing many chemical calculations.

Avogadro's constant can be used to calculate the number of moles that a given number of particles represents. The equation for this is:

moles (mol) =

Molar mass can be used to calculate the number of moles in a certain mass of a substance. This calculation can be used to determine:

• The amount of reactant required

• Which chemical is the limiting reagent

• The amount of product formed

• The mass of solid needed to make a solution with a given concentration

• To balance chemical equations

The equation for this is:

moles (mol) =

Concentration can be used to calculate the number of moles in a certain volume of a substance. This calculation can be used:

• To determine the concentration of a solution

• To prepare a standard solution

• When analysing the results of a titration experiment

The equation for this is:

moles (mol) = concentration x volume

Moles Revision Resources to Ace Your Exams

To explore cracking further, you should check out the revision notes on the mole and practise our exam questions to ensure success. Flashcards on the mole are also a great way to revise the wider topic before an exam. 

Explore our GCSE Chemistry revision resources.