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OCR Chemistry F322~ 4th June 2013~ AS Chemistry watch

  • View Poll Results: How did you find the exam
    Hard A= 72
    42
    15.22%
    It was okay A= 76
    99
    35.87%
    Easy A= 79
    75
    27.17%
    Very Easy A=82
    60
    21.74%

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    (Original post by redtortoise)
    Iput c-o and c=o but was really confused, I did put c=c first but got muddled
    I put the same, think you would still get a mark for c=o rather than ester
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    (Original post by Dizzie31)
    correct.
    the answer is 1640, 240/20= 10 moles 10x 164 to give 1640
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    (Original post by jacksonmeg)
    I put alkene and carbonyl, will that count ?
    a ketone is a carbonyl, but i'm not 100% sure whether it would be accepted
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    Could anyone upload the paper itself or the unofficial mark scheme?
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    (Original post by _Morsey_)
    Are you referring to that one with above 2.5 atmospheric pressure etc? For both i put it to shift left, with absence of catalyst slowing down the rate at which dynamic equilibrium is reached.



    Well it asked for two propagation stages, so i did;

    Initiation: IBr -> I. + Br.

    Propagation Step 1: CH4 + Br. > CH3. + HBr
    Propagation Step 2: CH3. + I2 > CH3I + I.

    Termination: Br + I > IBr etc.



    Thats what i did so i hope it is right :3

    Where does the I2 come from?

    I got

    Initiation: IBr -> I. + Br.

    Propagation Step 1: CH4 + Br. > CH3. + HBr
    Propagation Step 2: CH3. + IBr > CH3I + Br.
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    (Original post by massi1296)
    the answer is 1640, 240/20= 10 moles 10x 164 to give 1640
    There was 2 moles already in the original equation, not 1.
    10/2 = 5
    so you times it by 5.
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    For the answer after 820, was it 82?
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    (Original post by daisyrchds)
    same! seriously need to brush up on my octagon drawing skills though, re-drew it like 4 times
    i couldnt draw a branched 10 C alkane, took me 4 times to get the right amount of C ._.
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    i put ester c-o and alkene c=c
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    You can't just predict the Grade boundaries.. I know quiet a few people in my class who hates the paper if you thought it was easy you can't generalise tens of thousands who sat this paper lol
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    (Original post by dawg)
    Where does the I2 come from?

    I got

    Initiation: IBr -> I. + Br.

    Propagation Step 1: CH4 + Br. > CH3. + HBr
    Propagation Step 2: CH3. + IBr > CH3I + Br.
    i wrote that^
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    (Original post by Liberty.)
    Please tell me people just drew an octagon on the second page? I felt like an idiot
    i tried to but my octagon ended up more like a circle, so i redrew the cyclooctane putting CH2 at each corner just to emphasise what shape it was supposed to be :L
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    (Original post by irfymahmood)
    yeppp i did
    There was also a ridiculously small amount of room to draw an ester, with a carbon ring in it, in a puny box.
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    (Original post by jacksonmeg)
    I put alkene and carbonyl, will that count ?
    I wouldn't think you would get it for carbonyl
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    (Original post by kingmango)
    For the answer after 820, was it 82?
    yeah 164 / 2 i think
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    (Original post by Dizzie31)
    There was 2 moles already in the original equation, not 1.
    10/2 = 5
    so you times it by 5.
    isnt it /24 not /20 ?
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    (Original post by dawg)
    Where does the I2 come from?

    I got

    Initiation: IBr -> I. + Br.

    Propagation Step 1: CH4 + Br. > CH3. + HBr
    Propagation Step 2: CH3. + IBr > CH3I + Br.

    Yeh, i'm not quite sure why i put I2...
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    (Original post by Dizzie31)
    There was 2 moles already in the original equation, not 1.
    10/2 = 5
    so you times it by 5.
    the +164 was for 2 moles of the N20 formed so you didnt have to divide by 2
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    (Original post by jacksonmeg)
    isnt it /24 not /20 ?
    the volume was 240
    240/24 = 10
    10/2 = 5 .. Mole ratio
    5 x 164 or whatever = answer
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    (Original post by Dizzie31)
    yeah 164 / 2 i think
    Sweeeet.
    I'm thinking 82 for an A?
 
 
 
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