You can find all my A Level Chemistry videos fully indexed at https://www.freesciencelessons.co.uk/... In this video, we start exploring how to calculate the amount of a substance in moles. First we look at what is meant by the amount of substance in terms of carbon-12 and what is meant by the Avogadro constant. We then look at how to work out the molar mass for an element, a molecule and a giant structure. We finish by looking at how to calculate the amount of substance from a given mass of substance. This video is aimed at the UK A Level Chemistry specifications. Students studying International A Level Chemistry will need to check their specification.