C7/B7/P7 (OCR 21ST CENTURY) Revision thread for 2017 exams

The spec says

"recall the reaction of alcohols with sodium and how this compares with the reactions of water and alkanes with sodium"

so I think they could maybe give it as a 6 marker - you can write word and symbol equations and describing along with what happens in the reaction.

ah that would be so nice! just no chromatography please. i hate it so much.

But chromatography is nice...it's like fermentation methods you don't want.

noo i just don't understand the equilibrium between the two phases. i like the evaluating the sustainability, that's quite a good 6 marker when they ask you to look at feedstock etc like they did for last year. i really don't want an acid question like last year's because i found it worded very strangely. they didn't do haber process last year i don't think, which is quite surprising. also why are the grade boundaries so high?? is it because only private schools do it (not saying automatically people who go to private schools r good at science bc i am proof that's not the case))

It's mainly because some schools only let people take it if they've reached a certain level - eg the core boundaries are lower because everyone has to take it.

Those sorts of questions comparing are fine - it's just if we get asked the different types of ethanol production (eg hydration, E-coli bacteria and fermentation) It's just too much to learn.

yes, i find the 7s difficult because there's a lot more to learn (obviously as it's a whole unit) but it's very process-y

And, because it's a whole 60 marks, they usually test (almost) everything each year...so you basically have to know everything.

do we need to know how gas chromatography happens or basically just know it is a form of chromatography?

Someone explain chromatography equilibrium please??

I worry that the grade boundaries will be really high for this paper, as they're usually much higher than the other papers, and because it's the last year, they're likely to be even higher

Someone explain chromatography equilibrium please??

I think it's just that it's said to be in dynamic equilibrium because the amount leaving the stationary phase for the mobile phase is the same as the amount leaving the mobile phase for the stationary phase

Isn't it that each component has a dynamic equilibrium between the mobile phase and the stationary phase and so the spot that is more attracted to the mobile phase moves further, and vice versa? Just checking my own understanding here

I thought the movement was just because it was more attracted to the stationary phrase than the mobile phase (and vice versa)

I thought the movement was just because it was more attracted to the stationary phrase than the mobile phase (and vice versa)

I will not be able to cope tommorow in biology if the weather is the same as today