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OCR A2 CHEMISTRY F324 and F325- 14th and 22nd June 2016- OFFICIAL THREAD

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Reply 2380
Regardless of which fatty acid it is would I get the mark for justifying by saying "it has a linear structure so molecules pack to get her closely also trans/saturated fatty acids raise blood cholesterol levels? Do I have to say "bad/LDL" cholesterol?
Original post by Laurasaur
Ah, but define dissolve. You could have two liquids together that don't dissolve with each other, like if you put oil on water. Not a stupid question, I'm not 100% confident with my answer, but I'm mixing my chemistry and biology knowledge :s-smilie:


quite true i got retarded for not thinking that. i thought there are quite a few biochemistry questions in this paper, if they do require biology knowledge in answer, that would be a disadvantage for physics + chemistry combination ppl like me lol.
Original post by yiz
Ok cool, and do you think the formula for my fragment ion is ok?


where are the fragment ions?
Reply 2383
Original post by lai812matthew
where are the fragment ions?


I'll just write it again. This is it: H3CCH(NH2)+
Original post by four4
Do you think they'll award a mark for drawing the tripeptide as a repeat unit?


When doing last papers I've noticed that you can often get 1 mark for the amide linkage, so I'm sure if the rest of the structure is right you'll be able to get 1 mark
There was question where you had to draw a cyclic molecule right? With the lactic acid I think.
Original post by lai812matthew
quite true i got retarded for not thinking that. i thought there are quite a few biochemistry questions in this paper, if they do require biology knowledge in answer, that would be a disadvantage for physics + chemistry combination ppl like me lol.


I know what you mean, I doubt it would be a requirement, but it could be in the box for alternative answers or if they accept any valid point. Physics can have its little advantages too :wink:
Original post by yiz
I'll just write it again. This is it: H3CCH(NH2)+


I think that's what I put, as long as it adds up to mr 44 you should be fine
Reply 2388
Original post by CalistaJupiter
I think that's what I put, as long as it adds up to mr 44 you should be fine


Thank you 🤘
Original post by qhdop
Would I get a mark for saying that pla is biodegradable?


No because the stitches are within the skin hence in close contact with blood, they're not in the soil mate sorry
Original post by yiz
I'll just write it again. This is it: H3CCH(NH2)+


yeah that's correct i think eliminating CH2OH from original molecule
Original post by KB_97
There was question where you had to draw a cyclic molecule right? With the lactic acid I think.


ye
Original post by ToLiveInADream
f324, haven't done 2015 f325 yet


could you post the 2015 links here i cant seem to find them :/
Reply 2393
In the question with peaks, would I get the mark for peak 1 if I drew its formula without a positive charge?
Original post by qhdop
In the question with peaks, would I get the mark for peak 1 if I drew its formula without a positive charge?


If you missed out the positive charge then you will probably need both formulae correct to get 1 mark (out of 2).
Original post by lai812matthew
if that is the case then HCl would have been accepted also without writing diluted. they just don't allow concentrated HCl.

I put conc 😠
Original post by qhdop
In the question with peaks, would I get the mark for peak 1 if I drew its formula without a positive charge?


I did this too, slightly worried :/ I drew my second structure for peak 2 with a positive charge but as peak 1 was the overall compound it didn't make sense to me to draw it with a positive charge as it hadn't been fragmented
Original post by aegonsconquest
yh the fats 1, i think it was 1 right?


think so yeah
How many marks for a B grade ? Do u think
1465939797921-1945820337.jpg is this octa deca 12 enoic acid ?

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