do you mean chemistry to as-level? they say if you've only done it to AS level you have to go to extra chem lectures for the first half of the year until you start the proper ones, but i dont know anyone with AS chemistry who actualy did after the first week or two because it was just pretty basic stuff, nothing more than you learn AS anyway. even if you go to them all it isnt that bad because you just have to sit at the back and listen, you dont have to do any of the exams or coursework for them so it isnt actually any more work, you'll just have 3hrs a week less free time. the first proper chemistry module you do is pretty hard though... it seems more maths than chemistry and some of the equations and that you use and need are getting on for degree level maths ahha, but aside from that the others arent bad, thats the module out of all of them i found hardest