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    So for the polylactic acid question, I was just wondering what other people put my answer was structured like this;
    Polylactic acid is a condensation polymer (polyester)
    The ester bond hydrolyses --> c.acid + alcohol
    The monomer unit (lactic acid) is soluble in water so the stitches dissolve
    Anyone have similar/different points?
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    For the PLA question I wrote about how it can be hydrolysed in the body and then hydrogen bond with water molecules because of the polar cooh and oh group on lactic acid. I completely forgot about it being photodegradable too. Oh god..
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    the only hard thing in that exam for me was the NMR table and the tripeptide.


    I did the right splitting patterns, but wrong chemical shits
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    Was photodegradable correct??
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    (Original post by maisym00)
    Oh god, I wrote about them being photobiodegradavle on exposure to UV😕 Oops
    I did the exact same thing lol...
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    I thought about going for the photodegradable angle, BUT I decided against it bc when polymers photodegrade they break down into waxy residue and then turn into H2O and CO2 and that isn't really dissolving is it? Also I think photodegrading takes a while, longer than hydrolysis + dissolving would anyway
    Maybe I'm wrong tho
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    For the last question, if you get F wrong, you get G and I wrong too right? Meaning forgetting the methyl group and hence putting down a straight chain since G had 4 carbon environments so F would have had to had the methyl group? In this case, would you get 3/4 marks as you got F wrong, but G and I would be ecf? or would you just get 1/4 because you got F wrong hence G and I too?
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    (Original post by RayMasterio)
    the only hard thing in that exam for me was the NMR table and the tripeptide.


    I did the right splitting patterns, but wrong chemical shits
    You better stay on your toilet, then.
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    (Original post by Nightwing2241)
    Was photodegradable correct??
    can't be photodegradable if in body
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    On the last big question where you had to identify F,G etc, I specifically named them as : 3-methylbutan-2-ol, 3- methyl-butan-2-one, propanoic acid and 3-methylbutylpropanoate. And then I also drew out the structures as they asked.Would this lose me any marks as I think I’ve named them all fine, and gave the reasoning for H with the mr of 74. So do you just get marks for the structures, and do I not need to worry about the naming. Or do they want us to state ’secondary alcohol’ etc. Will my answers be right even though i haven’t explicitly stated what they are in generic terms?
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    (Original post by k.russell)
    I thought about going for the photodegradable angle, BUT I decided against it bc when polymers photodegrade they break down into waxy residue and then turn into H2O and CO2 and that isn't really dissolving is it? Also I think photodegrading takes a while, longer than hydrolysis + dissolving would anyway
    Maybe I'm wrong tho
    i said hydrolysed into h20 and c20 too, because of acid in the body though.
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    so what was answer thats worth 3 marks??
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    crap i put biodegradable instead of photodegradable

    that last question though!!! never fought so hard for 1 mark
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    (Original post by marioman)
    I talked about it being photodegradable. The thing that made me think that was the "technical terms spelt correctly". Photodegradable has been a 'spelling' mark on a previous paper.
    I think the QWC mark would have been for spelling hydrolysis
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    (Original post by Nightwing2241)
    so what was answer thats worth 3 marks??
    No-one knows the exact marking points.
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    Name:  image.jpeg
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    I got this for the last question. Compound J I think. Anybody else get this?
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    (Original post by Yazmin123)
    amide hydrolysis question with HCL did you get nh3+ for the amine that had the alcohol attached to it as well?
    Incorrect
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    Hmmm, I'm thinking that was a great test.

    In fact it was so easy that I think there are going to be really high grade boundaries this year.
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    (Original post by k.russell)
    So for the polylactic acid question, I was just wondering what other people put my answer was structured like this;
    Polylactic acid is a condensation polymer (polyester)
    The ester bond hydrolyses --> c.acid + alcohol
    The monomer unit (lactic acid) is soluble in water so the stitches dissolve
    Anyone have similar/different points?
    Should have wrote it forms hydrogen bonds with water which is why it dissolves
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    (Original post by mil88)
    Incorrect
    why?
 
 
 
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