Edexcel (Nuffield) Chemistry internal assessment [design / plan]

Argh - worth 7.5% of AS and I've got to do it on Friday!

The teacher has briefly gone through what is 'expected' but he's only outlined bits of it and I feel totally unprepared and not confident about it. My current mindset is just how on earth will I get a design / plan completed in one hour when a) I'm a slow thinker and writer, and b) I'm very meticulous about things like handwriting and being neat. Oh and not to mention, the actual content and theory I have to write!?

I understand how to calculate enthalpy changes and how to use a Hess cycle...etc but I'm not sure what we actually have to write about to gain top band marks.

30% of AS Edexcel (Nuffield) Chemistry is based on four of these and I can't afford to mess one up! I'm so nervous and it's made me feel like crap over the past week! I've tried talking to both teachers to get more out of them but they manage to get away from the matter in a conversation.

What can I do? I've barely got 48 hours to actually prepare for it! I feel I work better under pressure but what can I do to prepare for it? What can I plan or write beforehand and memorise that is bound to come up on the plan sheet?

Anyone who has done this before - please give me advice and tips!

Many thanks in advance.