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

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Original post by aegonsconquest
Screen Shot 2016-06-14 at 20.15.26.png

guys i got this as my fragment for m/z = 44
surely its right, right?


No, because then the NH2 group would be cut off. You can only split the compound once. Did it ask for you to draw the structure? I just wrote down the formula whoops
Reply 2321
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5824
1
What was the TLC question again?
Hii.What were the functional groups (other than phenol) in that molecule they gave
Original post by MrZebraCookie
No, because then the NH2 group would be cut off. You can only split the compound once. Did it ask for you to draw the structure? I just wrote down the formula whoops


formula
Original post by johnjims828
yeah i just read that in the textbook mate.normally doesn't mean it's a 100% certainty so it may still be accepted.

i agree, it may be one of those allow marks lol
Original post by Terrificmagenta
Hii.What were the functional groups (other than phenol) in that molecule they gave

Amide link, alcohol group
Original post by slugmonkey97
to be honest i think the test was harder than people think and because a lot of people thought they understood the questions and there was an easy nmr at the end is the reason people think the boundaries will be high, however i think the questions were sneakily harder than they seemed and a lot of people may have misinterpreted the questions, they also required a lot of quite detailed knowledge which some people overlook, such as the optical isomers one, i wouldnt be surprised if the grade boundaries were high 40s for an A.


I agree with this. Initially people thought they did well but then lots of these tiny things that they didn't know they got wrong came up.
How many chiral carbon atoms did you get? I got 2? Also for the conditions/reagents of the azo dye i put hno2 and hcl (conc) <10degrees will that be a mark? Or is it dilute hcl???
Original post by slugmonkey97
i agree, it may be one of those allow marks lol


CIE likes cancelling the whole question out if they made the question too ambigious
Original post by Manliker
How many chiral carbon atoms did you get? I got 2? Also for the conditions/reagents of the azo dye i put hno2 and hcl (conc) <10degrees will that be a mark? Or is it dilute hcl???


dilute hcl, nano2 not hno2.
Reply 2330
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aidab
3 chiral carbons they put a sneaky one in an R group
Is it really? I put down it's the first one (saturated one) because the the other did not say if it was cigs or trans.. So basing upon the assumption that it was trans but could have been a Cis isomers... So I just said the first one )thinking about which it has a trans structure anyway)
Original post by slugmonkey97
your answer for f only has 3 carbon envirnments as is symmetrical, earlier in the question you had to identify there were 4 carbon environments in f, therefore the structure is CH(CH3)2CHOHCH3 correct me if im wrong


**** youre right, damn how many marks would i lose with efc?
Reply 2333
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yiz
1
Guys for the nmr table, do you think I'd get the mark for the splitting pattern for saying "split into 6 "sub-peaks" " instead of writing "sextet" or "multiplet"
(edited 7 years ago)
Original post by Notahugetsrfan
mate saturated fatty acids caused increased ldl production, you're wrong just accept and stop being a berkshire hunt with your arrogant insistence


trans fatty acids increase ldl and also REDUCE HDL making them more life threatening than saturated fatty acids
Original post by hadkashk
Nah, it doesn't mention in the spec that photodegradable polymers break down into CO2 and H2O. If it were biodegradable then it would.


The texbook (OCR) states on page 61 "Photodegradable polymers are initially coverted to waxy compounds when exposed to light, before being converted to carbon dioxide and water in the presence of bacteria"
However I do not believe that this is the correct answer anyway. You are assuming that this is for external sutures and not internal. Poly (lactic acid) has a degradation time depending on presence of bacteria from around 47 days to 4+ years. An external stitch even at the shortest time of 47 days is far too long.

The textbook on page 55 states "Poly (lactic acid) is biodegradable" I believe the marks are for explaining that the ester link is broken via hydrolysis due to the presence of water in both tissue and blood and that the third is for stating PLA is biodegradable and therefore breaks into carbon dioxide and water. Hence dissolvable stitches.
Original post by hadkashk
I agree with this. Initially people thought they did well but then lots of these tiny things that they didn't know they got wrong came up.


You actually agree with you coz many friends of mine came out saying it was easy but I found question deceptive to say the least, for example the 3chiral carbon and not 2 .. These little things will eventually lead to ppl making many. Mistakes ..
Original post by aegonsconquest
ah ok, btw the 1st Q was 2 marks right>?


the first question as in the fats one or the fragment ion question? There were two marks for the fragment ion one- probably one mark for each structure
Original post by ozziew
Amide link, alcohol group


Thanks
Original post by Jamil_dow
**** youre right, damn how many marks would i lose with efc?


id presume youd only lose 1 mark for the structure of f, everything else would be ecf so dont worry about it, f325 counts so much more than this test so just focus on that, i have a feeling its going to be really hard...

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