You will be studying AQA A level chemistry and the CGP revision guide here is the main supporting text we recommend you purchase. It may also be worth considering an Essential Maths Skills for A-level Chemistry book here and the Head Start to A-level Chemistry here. There is also a great deal of GCSE work of which it is assumed you have a general knowledge of. If you feel you need a refresher on some of this, the set of revision notes here will support you. There are videos to watch on each topic, along with questions to have a go at.