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POST-EXAM CHAT: OCR Chemistry- Rings, Polymers and Analysis - F324 thread watch

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    (Original post by MHorman)
    You could put Dil HCL or NAOH(aq).

    Or any acid/alkaline if you put dil/(aq) in as well i think.

    My gut feeling is that they wanted us to realize that both drugs have acid groups which would be readily ionized in the presence of an alkali, the reason being is that they said organic product, not products which would be the case in hydrolysis
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    What ester everyone get for NMR question??
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    (Original post by Noble.)
    I got (CH3)2CHCOOCH3.
    yep that is what I got.

    I got this after like a page of working out and crossing out. I don't think the examiner will be able to see how I derived this answer
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    (Original post by jacko0892)
    What ester everyone get for NMR question??
    (CH3)2CHCOOCH3
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    the one on the top right corner is the ester i got?
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    (Original post by Noble.)
    I got (CH3)2CHCOOCH3.

    Same. thats correct
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    was the answer to the first anhydrife question just to draw a phenol and how would you draw the structure of the imputirty....
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    (Original post by Noble.)
    I got (CH3)2CHCOOCH3.
    legend! and what were the reagents for A, B and C?

    i got H2O, Ethanol and NaBH4 respectively.. you?
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    (Original post by New Username)
    yep that is what I got.

    I got this after like a page of working out and crossing out. I don't think the examiner will be able to see how I derived this answer

    Same. I'm so not getting the mark for quality of communcation, I was rushing like hell at that point, I only had three minutes to do the whole of the last question:eek3: !
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    (Original post by _Andrew_)
    Same. thats correct
    I made a very stupid mistake there. The Chemical shift from the databooklet confused me
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    (Original post by Pedus)
    legend! and what were the reagents for A, B and C?

    i got H2O, Ethanol and NaBH4 respectively.. you?
    H2O, NaBH4 and acidified potassium dichromate(VI) respectively.
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    (Original post by _Andrew_)
    Same. I'm so not getting the mark for quality of communcation, I was rushing like hell at that point, I only had three minutes to do the whole of the last question:eek3: !
    There wasn't a mark for quality of communication anywhere, I thought?
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    (Original post by Noble.)
    NaBH4 does reduce -COOH. All NaBH4 and LiAlH4 do is provide H- ions.
    true, but it's about how easilly they provide those ions. The B-H bonds are stronger than the Al-H bonds, which is why LiAlH4 is the stronger reducing agent. Think back to Halogenalkanes. NaBH4 isn't strong enough to reduce a -COOH group.

    Whether they give the marks however, is a different story, since, like I said, it's beyond the scope of Chem A Level.
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    (Original post by monkey01)
    was the answer to the first anhydrife question just to draw a phenol and how would you draw the structure of the imputirty....

    I think that was what I done.
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    (Original post by Noble.)
    H2O, NaBH4 and acidified potassium dichromate(VI) respectively.
    interesting. why the dichromate on the last one though? surely it was NaBH4 as there was a COOH on the Phenol!

    and the ethanol on the second one would have broke the ester link!
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    (Original post by TwilightKnight)
    true, but it's about how easilly they provide those ions. The B-H bonds are stronger than the Al-H bonds, which is why LiAlH4 is the stronger reducing agent. Think back to Halogenalkanes. NaBH4 isn't strong enough to reduce a -COOH group.

    Whether they give the marks however, is a different story, since, like I said, it's beyond the scope of Chem A Level.
    In both of the Chemistry books I used for the course, there's no mention of using anything other than NaBH4 for reducing a carboxylic acid.
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    (Original post by TwilightKnight)
    Er… it was 3 amino acids, but it was the same monomer unit. It just alternated up and down. It asked for the single monomer that it was made of, which was valine.

    Unless I started imagining things halfway through the paper, which now worries me.
    the sequence was valine, glycine, and leucine?
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    (Original post by Noble.)
    There wasn't a mark for quality of communication anywhere, I thought?

    I think there was two, one at the start about bromination of the different compounds, and also for the NMR question.
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    (Original post by Pedus)
    interesting. why the dichromate on the last one though? surely it was NaBH4 as there was a COOH on the Phenol!

    and the ethanol on the second one would have broke the ester link!
    I said NaBH4 for whichever one had the benzoic acid, I can't remember the order.
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    The NMR spec was SO easy! i was expecting a real hard interpretation of IR, MS, and protonNMR,
    i feel like full marks up until the last 3 pages tbh lol
 
 
 
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