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OCR Salters Chemistry B F332 Advance Notice May 2011 Polymers on the move watch

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    What is meant by Crystalline?

    Crystalline
    Regions have a high degree of order/ regular/ chains more aligned (1);
    the chains move over each other less easily (1);
    because there are stronger imf (1); (IGNORE “more imf”)
    due to molecules being closer together (1)
    I don't think the idea of crystalline is in the spec anymore.
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    (Original post by Bi0logical)

    What is meant by Crystalline?

    Crystalline
    Regions have a high degree of order/ regular/ chains more aligned (1);
    the chains move over each other less easily (1);
    because there are stronger imf (1); (IGNORE “more imf”)
    due to molecules being closer together (1)
    Thanks!

    But, a couple of weeks back I was doing an old spec past paper that had a question on crystalline polymers on it - I'd never heard the term crystalline, so I asked my teacher, and she said it was old spec and we didn't need to know it any more...

    Can anyone confirm if it's still in the spec? I can't find it in the revision guider either!
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    (Original post by Toshiya)
    Thanks!

    But, a couple of weeks back I was doing an old spec past paper that had a question on crystalline polymers on it - I'd never heard the term crystalline, so I asked my teacher, and she said it was old spec and we didn't need to know it any more...

    Can anyone confirm if it's still in the spec? I can't find it in the revision guider either!
    Im pretty sure it isnt, it's not in any of the textbooks...
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    I remember seeing crystalline and amorphous in the chemical ideas somewhere? Maybe not for F332..
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    (Original post by gozatron)
    I remember seeing crystalline and amorphous in the chemical ideas somewhere? Maybe not for F332..
    I think it's been moved to A2.
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    (Original post by Hudzy)
    Yeah I took it off the internet without realising it had an extra carbon. I posted an updated version but you probably missed it. I'll change the version on the old post to stop confusing people

    Here is the update anyway.
    You are my hero! - For the revision polymer thing :L
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    (Original post by gozatron)
    Anyone got a handy list of the reaction reagents and conditions we need to know?

    The Jan 11 paper and Mark scheme would be pretty handy aswell

    Thanks
    Did you find a list of the reagents and conditions?
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    Anyone know exactly what points the mark scheme are looking for when they ask how ID-ID, PD-PD and H bonds are formed?
    I always trip up on the wording with those questions!
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    (Original post by Toshiya)
    Anyone know exactly what points the mark scheme are looking for when they ask how ID-ID, PD-PD and H bonds are formed?
    I always trip up on the wording with those questions!
    ID-ID

    Electron movement causes an uneven distribution of charge. This induces a dipole in a neighbouring molecule, followed by attraction.

    PD-PD

    Simply one atom more electronegative than the other (explain that method if necessary) in a covalent bond, so PD-PD formed between different atoms of each molecule.

    Hydrogen bond

    Slightly positive H atom is attracted to the lone pair on an oxygen atom so H bond formed.

    Key marking points underlined.
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    the person that did the polymers on the move sheet is a GENIUS! MUCH LOVE FOR YOU!!
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    (Original post by icedragon)
    ID-ID

    Electron movement causes an uneven distribution of charge. This induces a dipole in a neighbouring molecule, followed by attraction.

    PD-PD

    Simply one atom more electronegative than the other (explain that method if necessary) in a covalent bond, so PD (not PD-PD ) formed between molecules.

    Hydrogen bond

    Slightly positive H atom is attracted to the lone pair on an oxygen atom so H bond formed.

    Key marking points underlined.
    Thanks! That's exactly what I wanted, whenever I answer a question like that I just waffle and still only manage to put in half of the points.
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    (Original post by gozatron)
    Anyone got a handy list of the reaction reagents and conditions we need to know?

    The Jan 11 paper and Mark scheme would be pretty handy aswell

    Thanks
    Try the spec, there's some, in that...

    I bloody hate those reaction conditions. :rant:

    EDIT: page 21.
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    (Original post by Toshiya)
    Thanks! That's exactly what I wanted, whenever I answer a question like that I just waffle and still only manage to put in half of the points.
    No problem. Just to note, it is PD-PD apparantly (I guess because its between 2 molecules and not intramolecular). Also remember to spell ID-ID and PD-PD out fully and correctly especially if there are any QWC marks.
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    (Original post by icedragon)
    No problem. Just to note, it is PD-PD apparantly (I guess because its between 2 molecules and not intramolecular). Also remember to spell ID-ID and PD-PD out fully and correctly especially if there are any QWC marks.
    Cheers.
    And yeah, I know now to write them out fully... found out the hard way when I lost marks on a couple of mocks we did in class because I just put 'ID-ID'
    Turns out if they ask for QWC marks on a question like that you often get them for spelling instantaneous and induced correctly.
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    (Original post by Toshiya)
    Cheers.
    And yeah, I know now to write them out fully... found out the hard way when I lost marks on a couple of mocks we did in class because I just put 'ID-ID'
    Turns out if they ask for QWC marks on a question like that you often get them for spelling instantaneous and induced correctly.
    Yep, or for linking your ideas together. So for example when describing how CO2 warms the Earth, you would get a QWC for saying "UV from the sun is absorbed by the Earth which heats the Earth and in turn it emits IR". Connection of ideas will get you that mark really.
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    Just wondering if anyone has any sort of notes on the entire specification, or sheets similar....
    I could do with some cramming material to read through tomorrow
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    Worth knowing about free radical polymerisation (free radical addition):

    The chain is initiated by radicals produced by the reaction between the alkene and an oxygen initiator. When these radicals meet a longer free radical is formed:



    This chain continues:



    Until termination where two of the radicals meet making a final molecule:



    It's important to note that the chain termination is random, because 2 radicals could meet at any time (between long chains or short chains), so the polymer itself will be made up of chains of all different lengths.
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    icedragon... I've never heard of free radical polymerisation.
    I'll be having words with my chemistry teachers when we go back if that comes up tomorrow and I can't do it >_>
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    (Original post by icedragon)
    Worth knowing about free radical polymerisation (free radical addition):

    The chain is initiated by radicals produced by the reaction between the alkene and an oxygen initiator. When these radicals meet a longer free radical is formed:



    This chain continues:



    Until termination where two of the radicals meet making a final molecule:



    It's important to note that the chain termination is random, because 2 radicals could meet at any time (between long chains or short chains), so the polymer itself will be made up of chains of all different lengths.

    icedragon you really are a respected and adored member, if it wasn't for you and hudsy i wouldn't have had a shot at this exam

    THANKS
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    (Original post by Toshiya)
    icedragon... I've never heard of free radical polymerisation.
    I'll be having words with my chemistry teachers when we go back if that comes up tomorrow and I can't do it >_>
    It's basically the actual mechanism for addition polymerisation (it's how they add together). I think it's in the syllabus as it's in some of my guides but if it isn't, it could quite possibly be useful for the advanced notice question. I quote from the advanced notice:

    "These are polymerised by a free radicalinitiated polyaddition." - from the Bonding polyalkenes section.

    So they could very possibly ask you about the mechanism I explained.

    (Original post by bugsymalone)
    icedragon you really are a respected and adored member, if it wasn't for you and hudsy i wouldn't have had a shot at this exam

    THANKS
    No problem . If there are any other mini-topics you would like explaining just shout. And what baffoon neg'd you?
 
 
 
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