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

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    (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.
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    (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 ..
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    (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
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    (Original post by ozziew)
    Amide link, alcohol group
    Thanks
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    (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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    (Original post by yiz)
    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"
    sorry dude but I reckon the markscheme is kind of clear cut with
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    (Original post by aidab)
    sorry dude but I reckon the markscheme is kind of clear cut with
    there is a same type of question on jan 2013 and it allows all of the choices.
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    what was the impurity formed?
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    (Original post by lai812matthew)
    there is a same type of question on jan 2013 and it allows all of the choices.
    fair play then sounds like you got the mark haha
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    (Original post by aidab)
    sorry dude but I reckon the markscheme is kind of clear cut with
    Ok thanks
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    (Original post by lai812matthew)
    there is a same type of question on jan 2013 and it allows all of the choices.
    Really?? Good cos I've been so paranoid about it
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    (Original post by yiz)
    Really?? Good cos I've been so paranoid about it
    that's because the real answer should be quartet of triplets, but this is not in the spec. when they set multiplet as the initial answer for jan 2013, teachers were unhappy, so it turns out there are around 6 acceptable answers lol.
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    Mark scheme https://goo.gl/gEi388
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    for the fermentation of sugars and chemical synthesis one i said chemical synthesis would make 2 optical isomers but fermentation of sugars would make 1, is this correct?
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    my experience A would be high 40s like 48 but definitely less than 50 marks ...ps I always win my bets In
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    (Original post by beckyingham)
    for the fermentation of sugars and chemical synthesis one i said chemical synthesis would make 2 optical isomers but fermentation of sugars would make 1, is this correct?
    that's what i write
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    (Original post by Mr Average.98)
    my experience A would be high 40s like 48 but definitely less than 50 marks ...ps I always win my bets In
    i don't bet at exam period cause i think it will lose all my luck......
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    Do you think they'll award a mark for drawing the tripeptide as a repeat unit?
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    >Worrying about how you did in an exam when there's no way to change it
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    Do you think this is unambiguous enough for the mass spec fragment ion: H3CCH(NH2)+ ??

    Also other than saying the isoelectric point is the pH for the zwitterion, is it correct to say the zwitterion is "a dipolar ion with no overall charge" ?

    A reply would be much appreciated!!
 
 
 
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