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    What do people think the grade boundaries will be like? Considering people generally thought it was a hard paper..
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    (Original post by tom108)
    For the wave number one i put c=o at 1750???
    (Original post by dan1993)
    i think it asked for an absorption above 1750
    sorry mate
    I doubt it is that. I think you can put that as the absoroption ranges from 1700 - 1725 but i dont think they were looking for that bond. I put the O-H bond to be on the safe side with an absorption of 2500-3200.
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    (Original post by lily92)
    What do people think the grade boundaries will be like? Considering people generally thought it was a hard paper..
    I think around 67% raw marks for A, 60% raw for B and so on.
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    2C6H5CH2COOH(aq) + CaCO3(s) -> (C6H5CH2COO)2Ca(aq) + CO2(g) + H2O(l)


    C6H5CH2COOH could also be written as C8H8O2.

    I got this so wrong! D:

    I said synthons aren't used because it would be much easier to do an electrophilic substitution reaction. I think the best answer would be to say the synthons don't really exist.

    Arguments for use of herbicide:
    It is quickly broken down in the soil so does not persist and bioaccumulate.
    ??

    The curly arrow went from the bond to the carbon atom:
    http://en.wikipedia.org/wiki/Synthon

    Love how I know answers after the exam but not in it! :|
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    (Original post by ManPowa)
    Question 3 - 20 marks

    molecular formula : C8 H8 02

    Equasion: phenylethanoic acid + calcium carbonate >>>> ????

    Curly arrow on the retrosynthetic analysis - From the Ch2 to the CO BOND

    Explain why synthons are not used to make the required compound.

    Nucleophilic substituition : Swap the CN with the Br and then leave the bromine as Br-

    Data sheets reageants : H+/H20/ with reflux

    Predict: As the forward reaction is exothermic, the equilbrium shifts to the left to absorb the heat and counteract the change. The equilibrium constant Kc, shall decrease..

    circled functional group : ether
    Functional in IAA BUT NOT IN THE OTHER TWO : Amine

    Wavenumber : O-H bond at a peak of 2500 - 3200 cm-1

    Circle just the carboxylic acid group.. this is the common pharmacophore in all 3 molecules

    Formula of the salt : someone has previously posted the exact answer

    Suggest why it is converted into a salt : I put to control the soil pH :/ lol and then i added salts are ionic which are water soluble.. Hmm... Answer people ..!!

    2 arguments :
    Inexpensive (cheap), use in small concentrations. anything else.. !!!
    can you scan the paper in pretty pleaseee
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    (Original post by bala123)
    I think around 67% raw marks for A, 60% raw for B and so on.
    I'd be surprised if it was that low. I mean, it was a hard paper, but I'd expect it to be at least over 70%...
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    Functional in IAA BUT NOT IN THE OTHER TWO : Amine -- was it a secondary amine??
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    (Original post by lily92)
    What do people think the grade boundaries will be like? Considering people generally thought it was a hard paper..
    Anyone's guess on this one! It wasn't a technically hard paper, but judging by the reaction, people felt it didn't go well. That isn't necessarily an indicator of difficulty though. And since boundaries get done before the exam is sat, they might be reasonably high. I don't reckon lower than 83/4 though for an A. They might adjust if lots of people do do badly though.
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    (Original post by jimmeh)
    I'd be surprised if it was that low. I mean, it was a hard paper, but I'd expect it to be at least over 70%...
    Wasn't Januray 2011 somewhere about 67% for an A ? I thought the one we did today had a few more tricky bits to it


    Seriously?! Grade boundaries get set before we actually take the exam? I though they take into account how everyone did and then set boudaries :/
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    i put a CH bond 2950cm-1 ???
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    For jan 2011 grade boundaries were:
    Raw 120 80 71 63 55 47 0
    UMS 120 96 84 72 60 48 0

    For june 2010 grade boundaries were:
    Raw 120 85 76 67 58 49 0
    UMS 120 96 84 72 60 48 0
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    (Original post by b3mine)
    Functional in IAA BUT NOT IN THE OTHER TWO : Amine -- was it a secondary amine??
    Yeah it was. There was also alkene
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    (Original post by b3mine)
    Functional in IAA BUT NOT IN THE OTHER TWO : Amine -- was it a secondary amine??
    i said alkene lol coz the other ones were benzenes :/ idunno tho
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    (Original post by b3mine)
    Functional in IAA BUT NOT IN THE OTHER TWO : Amine -- was it a secondary amine??
    Yeah your right, it was a secondary amine, but i suppose amine on its own will be acceptable
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    (Original post by Paolat)
    i said alkene lol coz the other ones were benzenes :/ idunno tho
    Same... benzenes are arenes not alkenes, at least I hope! They don't strictly have C=C bonds unless you use the outdated kekule structure.
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    (Original post by jungdao)
    Same... benzenes are arenes not alkenes, at least I hope! They don't strictly have C=C bonds unless you use the outdated kekule structure.
    Nah, they're was the kekulee structrue and alkene in all of them.
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    (Original post by b3mine)
    Wasn't Januray 2011 somewhere about 67% for an A ? I thought the one we did today had a few more tricky bits to it


    Seriously?! Grade boundaries get set before we actually take the exam? I though they take into account how everyone did and then set boudaries :/
    It was, and though there were a few funny bits in it, the majority wasn't too bad, so it won't be the lowest ever. January had a lot of strange long answer Qs which always drags down the boundaries, because even people who are gonna get A* miss bits/not word stuff like in the MS!

    Yeah, they are supposed to get set before purely on the difficulty, but the board can adjust boundaries if everyone does really badly/well. If it wasn't like this, all the further maths papers (for example) would be impossible to do well on, since people generally only take FM if they're gonna get C or more.
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    (Original post by jungdao)
    Same... benzenes are arenes not alkenes, at least I hope! They don't strictly have C=C bonds unless you use the outdated kekule structure.
    yeah, hopefully Lol
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    (Original post by jungdao)
    Same... benzenes are arenes not alkenes, at least I hope! They don't strictly have C=C bonds unless you use the outdated kekule structure.
    (Original post by tom108)
    Nah, they're was the kekulee structrue and alkene in all of them.
    The answer was (secondary) Amine nothing else.. not alkene or benzene.
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    (Original post by tom108)
    Nah, they're was the kekulee structrue and alkene in all of them.
    I think thats how benzene rings are drawn if its more than two rings because in the revision guide naphthalene and anthracene were drawn that way so i doubt it would be the kekule structure
 
 
 
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