We've just finished Unit 4. I absolutely hate Unit 4 - no idea what people are talking about when they say it's easier than AS Chemistry, I'm finding it harder than A2 Maths, Further Maths and Physics combined. Thank god we're onto Unit 5 now, I hate organic chemistry. The only slightly redeeming feature is NMR which is pretty fun, but I'm just sick and tired of all the endless learning of mechanisms and flipping reaction conditions - why on earth do we need to learn reaction conditions?!