Brainmelt nope, haven't come across a list of what was/wasn't on Chemistry Paper 1. Will let you know if anything comes to light.
DS has settled in to a rhythm of doing a maths paper and a science paper a day, plus looking over any gaps that emerge. Next exam not until Thursday so the pace has definitely dropped. I'm bracing myself to suggest that he ups it to 2 science papers a day (plus a maths) from Monday. The science papers are only an hour long (1 hour 15 mins for him) so definitely do-able. Whether he will or not remains to be seen.
Someone asked days ago for any tips for future gcse-takers. The only thing I'd add to the excellent advice already given is that they should make sure they're really familiar with the spec and map where they are on it as the course progresses (if that makes sense). That way they'll know if they've missed anything on a topic and will have a good idea of the shape of the course. It should help with note-making and organisation as they go along.
I am hoping DS will do this at A Level/Pre U and am imagining beautifully organised folders with complete notes and a well-thumbed spec ticked off as each topic is completed. Unfortunately this would probably require a personality transplant...