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Edexcel paper 2 chem unofficial mark scheme Watch

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    considering a A was 69% for the As last year and the intelligence of people sitting the exam hasn't changed id predict a 80% A*
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    For the 24 DNPH I.made a silly mistake.It and assumed you know which Sample had what compounds, but then I proceed with the question the way you did.Do I lose a mark?
    Were you means to say unknown Sample?
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    (Original post by ChloeClow)
    i got 94.2% for the paracetamol question...
    Mr was 151, remember number of moles?
    was it like 3.1*10^-3
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    (Original post by bobby147)
    For the 24 DNPH I.made a silly mistake.It and assumed you know which Sample had what compounds, but then I proceed with the question the way you did.Do I lose a mark?
    Were you means to say unknown Sample?
    Depends entirely on your wording, im afraid i dont know, you may lose a mark but it doesnt sound likely
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    (Original post by glad-he-ate-her)
    Mr was 151, remember number of moles?
    was it like 3.1*10^-3
    oh no.. i got 152 for molar mass... my bad Do you think I'll get ecf marks or something?
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    (Original post by ChloeClow)
    oh no.. i got 152 for molar mass... my bad Do you think I'll get elf marks or something?
    Maybe 1 working mark out of 2
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    (Original post by hc__)
    Okay I have no idea what was going through my mind but for the 2,4-DNPH question I said react them with potassium dichromate to oxidise them and then mix with 2,4-DNPH - if an orange precipitate forms then it is a Kentone and if it doesn't then it was an aldehyde but has been oxidised to a carboxylic acid which doesn't form the precipitate ... is that complelty wrong?
    Yes it is quite wrong, it wanted you to get at the fact that we can identify 2,4 dnph derivatives by measuring mp and comparing with data book
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    (Original post by ChloeClow)
    i got 94.2% for the paracetamol question...
    I got the same

    ahhh i see where i did wrong now
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    (Original post by otter.sty)
    I got the same
    (Original post by ChloeClow)
    oh no.. i got 152 for molar mass... my bad Do you think I'll get ecf marks or something?
    https://www.google.co.uk/search?q=pa...hrome&ie=UTF-8
    Paracetemols molar mass is 151, number of moles was? i cant remember
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    (Original post by glad-he-ate-her)
    https://www.google.co.uk/search?q=pa...hrome&ie=UTF-8
    Paracetemols molar mass is 151, number of moles was? i cant remember
    Your answer is correct, I also got 93.62%.
    They either got the Mr wrong or probably forgot mg means you times by 10^-3.
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    (Original post by bobby147)
    Your answer is correct, I also got 93.62%.
    They either got the Mr wrong or probably forgot mg means you times by 10^-3.
    Thanks for support! thought i did something silly there
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    what was the bromine concentration question? (I don't remember it and now i think i may have missed out an entire question)
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    (Original post by glad-he-ate-her)
    Organic synthesis- conc no3, conc h2so4 goes to nitrobenzene then add tin and conc hcl to phenylamine then add ethanoyl chloride ( with no halogen carrier) to desired product
    Ea was 84000 nearabouts joules, and divide for kj
    mass of nitrogen was 21.97
    Orders were x-1 y-2 z-0 k was 241.11
    Diff proton nmr, one had 5 one had 4 intensity was like 3 to 2 to 2 to 1 and 1 to 2 to 2 to 2 to 1
    find chemical shifts from data booklet and state splitting patterns
    24 DNPH derivates, orange crystalline forms, recrystallise ppt, find mp using capillary tube method- compare with database of known bradys reagent derivatives
    catalyst was adsrorbption, bond weakening then desrorption- explain those terms
    graphie and graphene was single layer of hexagons, bond angle 120 and poor electrical conductivity was answer
    reforming equation was just make cyclic and balance with hydrogen
    2NO+2CO---2co2 +N2 was an answer
    conc of bromine was 0.255
    paracetomal percent was 93.6
    Are you definitely sure about the proton nmr? In the new spec paper 2 there's a question on completing a nmr spectrum and it gives you the benzene hydrogens as a single peak with intensity 5... For for phenylethanal I got 3 peaks 5 to 2 to 1 singlet to doublet to triplet and for phenylethanone I got 5 to 3 singlet to singlet... anyone else?
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    (Original post by lizzie1414)
    what was the bromine concentration question? (I don't remember it and now i think i may have missed out an entire question)
    Gave us rate equation, some concs and k and said to find br conc
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    (Original post by Hazzagriff)
    Are you definitely sure about the proton nmr? In the new spec paper 2 there's a question on completing a nmr spectrum and it gives you the benzene hydrogens as a single peak with intensity 5... For for phenylethanal I got two peaks 5:2:1 singlet:double:triplet and for phenylethanone I got 5:3 singlet:singlet... anyone else?
    In benzene they are all in the same environment, when you add a group they become in different environments as they are differnt distances from the group which affects them.
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    (Original post by glad-he-ate-her)
    In benzene they are all in the same environment, when you add a group they become in different environments as they are differnt distances from the group which affects them.
    Can you explain this? Not saying you're wrong I just don't know
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    (Original post by glad-he-ate-her)
    mass of nitrogen was 21.97
    Was the mass of nitrogen in grams or kg?
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    (Original post by MaxA2C)
    Was the mass of nitrogen in grams or kg?
    Grams i think
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    (Original post by glad-he-ate-her)
    Grams i think
    ah, because I got 1000x your answer haha because the units given were Kpa so I multiplied by 1000
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    (Original post by Hazzagriff)
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    Can you explain this? Not saying you're wrong I just don't know
    They are technically in different hydrogen environments but the difference is insignificant and they overlap so we can consider them to be the same
 
 
 
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