1)organic chemistry(all equations and thier rquirements eg catalyst,temp etc and thier properties and uses)
2)metals
3)sulphur and nitrogen (all equations and thier requirements and what are the properties of reversible equations and uses)
4)everythin about reactivity series and thier properties and reactions (even electrloysis)
5)polymerisations (their types and uses and how terlene and nylons are made and what are thier uses)
6)properties and understanding and drwaing of ionic,covalent and metallic bondings
7)properties od groups in periodic table
8)basic stuffs about solid liquids and gases and thier properties
9) how to do calculations in chemistry
it mostly about everythin but i think this is more convenient to start with.
and do practise past papers
all revision of these things take about maximum 3 days