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OCR A Chemistry Paper 2 Unofficial Mark scheme Watch

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    (Original post by Boss987)
    71% yield.
    Did anyone get 95 repeat units?
    Ester for hydrogen NMR. This includes 3 CH3.
    At the end L was a Ester: CH3CH2COOCH2C(CH3)2CH3
    M was a carboxylic acid: CH3CH2COOH
    N was an alcohol : HOCH2C(CH3)2CH3 (Ashleigh)
    recrystallisation for the method.
    Phenol with ethanone joined together. for C NMR.
    https://www.thestudentroom.co.uk/att...2&d=1497870262
    Butan-1-ol + 2O] --> Butanoic acid and Water, using acidified potassium dichromate and under reflux
    Butan-1-ol + [O] --> Butanal and water, using acidified potassium dichromate and distillation technique (AnnaRainbows)
    Diol more soluble as it has two hydroxyl groups.
    Alcohol forms h bonds with water so soluble.
    https://www.google.co.uk/url?sa=i&rc...97957876618458
    Beta carotene Q
    C40H56 + 11H2 --> C40H78 (TuffyandTab)

    MCQ
    BDCBDCACCBCAACB (tamoni4)
    AgNo3
    C7H14 - molecular formula
    Addition reaction (economy)
    Trigonal planar - Atom no. 3
    3 peaks for NMR in MCQ
    3 or 4 Chiral carbons??
    Acyl chloride + primary amine = amide MCQ
    Alicyclic and saturated??

    Good Paper!!!
    I'm pretty sure the formula for β-carotene, according to OCR, was not C40H56. I think it was C40H44. If you want I'll explain my reasoning, but I've seen them do something like this before where they simplified what actually happens.

    It was a question where ammonia is added dropwise to a complex solution. We know that it causes a precipitate to form and they wanted a reaction. The actual reaction was the complex ion + ammonia but in the mark scheme they put OH- instead, even though it's almost impossible for the OH- ions to react with the complex solution rather than ammonia
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    (Original post by Paulina0)
    Phenol with ethanone joined together. for C NMR.
    https://www.thestudentroom.co.uk/att...2&d=1497870262


    For this I think it's wrong because on this picture you have 8 carbon environments and you needed 6 because there were only 6 peaks so you needed to put OH where it would make 6 environments
    That is 6 dude
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    (Original post by Paulina0)
    Phenol with ethanone joined together. for C NMR.
    https://www.thestudentroom.co.uk/att...2&d=1497870262


    For this I think it's wrong because on this picture you have 8 carbon environments and you needed 6 because there were only 6 peaks so you needed to put OH where it would make 6 environments


    http://www.chemicalbook.com/Spectrum...3-4_13CNMR.htm
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    how many marks was the repeat units question?
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    How many carbon envronments were there for the phenol ketone compound on the CNMR
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    (Original post by FrustratedHorse)
    How many carbon envronments were there for the phenol ketone compound on the CNMR
    6 environments, 8 carbons
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    (Original post by ChrisSteevo)
    how many marks was the repeat units question?
    If you're talking about the one where we draw the repeat unit with why it is easily biodegradable, that was 3 marks, assuming 2 for the repeat and 1 for the reasoning.

    If you're talking about drawing the separate compounds in the repeat unit shown, that was 2 marks, 1 for each.

    Hope you did well!
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    (Original post by FrustratedHorse)
    How many carbon envronments were there for the phenol ketone compound on the CNMR
    there was 6
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    (Original post by harry1208)
    If you're talking about the one where we draw the repeat unit with why it is easily biodegradable, that was 3 marks, assuming 2 for the repeat and 1 for the reasoning.

    If you're talking about drawing the separate compounds in the repeat unit shown, that was 2 marks, 1 for each.

    Hope you did well!
    Thankyou! It went well i think. How did you find it?

    There was a question below the two monomers about the number of repeat units there was. Just checking cos I missed it out
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    was one of the naming hex-3-en-1ol
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    Grade boundaries people??
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    (Original post by Lucy_starnes)
    What was the answer to the multiple choice about 0.1 mol and 0.1 mol makes how many atoms?
    6.02x10^22 i believe

    0.1 x 6.02x10^23 = 6.02x10^22
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    (Original post by ChrisSteevo)
    how many marks was the repeat units question?
    1 mark
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    (Original post by somebodyelse98)
    was one of the naming hex-3-en-1ol
    i put the same!
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    (Original post by chazer154)
    Grade boundaries people??
    Highest ive seen in past papers is 92-A*, 87-A, 76-B but then again who knows how everyone found it
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    For the IUPAC I had trouble naming the compound. I wrote hexene-3-ol. Would this suffice?
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    (Original post by Lucy_starnes)
    What was the answer to the multiple choice about 0.1 mol and 0.1 mol makes how many atoms?
    I put 6.02x10^22 because the ratio was one to one but I've seen other people put 3.01x10^22 so idk anymore
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    The last question never asked for the structures of M and N tho
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    (Original post by TheAlphaParticle)
    but there was no C-O bond in the CNMR diagram, so how could it be phenol??
    i think its different for carbons in benzene not sure tho
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    If i put "the impurities crystallize out" for the six marker but put everything else correctly, how many marks would i lose?
 
 
 
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