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

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    can someone please help me...

    Explain and describe, in terms of intermolecular bonding, the difference in properties between thermoplastics and thermosets?
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    For oxidising a primary alcohol to an aledehyde, what are the reagents and conditions???

    potassium dichromate, sulfuric acid and is it heat or distil???

    some papers allow heat but some dont
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    Heya, could someone please give me mark scheme definitions of a ...
    nucleophile and an electrophile please
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    (Original post by qwerty123qwertyu)
    For oxidising a primary alcohol to an aledehyde, what are the reagents and conditions???

    potassium dichromate, sulfuric acid and is it heat or distil???

    some papers allow heat but some dont
    Acidified Potassium Dichromate, Heat and distill as product forms.
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    (Original post by Cleoleo)
    Heya, could someone please give me mark scheme definitions of a ...
    nucleophile and an electrophile please
    Nucleophile is molecule or negatively charged ion with a lone pair of electrons that can be donated to a slightly positive charged carbon atom to form a covalent bond.
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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
    Here's the Jan 11 stuff for you!

    Advance Notice: http://www.mediafire.com/?0pk0cr3uc1x9oyi
    Paper: http://www.mediafire.com/?qb1mp9ptswq9qli
    Mark scheme: http://www.mediafire.com/?t332tw0pn2bcgc4


    I haven't done much in the way of revision for the advance notice... I'm gonna go over that tonight and glance over the stuff again in the morning.
    I'm currently getting mid-high 70s in practice papers... sure it's a low A, but an A's an A, right?
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    has anyone get any ideas what the main questions in the rest of the paper may be aimed at?
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    (Original post by polkadotty)
    can someone please help me...

    Explain and describe, in terms of intermolecular bonding, the difference in properties between thermoplastics and thermosets?
    I think that this would just mean thermosets have extensive crosslinks, thermoplastics don't have crosslinks, but i'm not 100% sure
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    The atmosphere is the worst module ever.
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    (Original post by gozatron)
    The atmosphere is the worst module ever.
    Wouldn't mind either the 6 mark question on CFCs causing ozone depletion or the explanation of greenhouse effect. They come up so often that I've memorised the marking points. Both were on January 2010 so I hope they're coming around again.
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    (Original post by Hudzy)
    Wouldn't mind either the 6 mark question on CFCs causing ozone depletion or the explanation of greenhouse effect. They come up so often that I've memorised the marking points. Both were on January 2010 so I hope they're coming around again.
    That would be too nice of them, it'll probably be something similar to the Jan 11/Jun 10 one (?) which asked something like "How did the scientists measure Ozone loss" or even worse
    If they ask something about climate models...
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    (Original post by Hudzy)
    Wouldn't mind either the 6 mark question on CFCs causing ozone depletion or the explanation of greenhouse effect. They come up so often that I've memorised the marking points. Both were on January 2010 so I hope they're coming around again.
    Ooh yeah, I wouldn't mind those either...
    Looking over the January 2011 paper, the stuff I don't think is likely to come up is explaining how ID-ID bonds or H bonds form... there was a huge 7-marker on that and solubility of polymers.
    There was a massive question on ozone in the troposphere as well, so I'm hoping that doesn't come up, since I always get my wording muddled trying to explain that!

    I hope I do alright on the advance notice stuff, looking at past papers I seem to trip up mainly on the questions to do with advance notice... that's maybe because on all the past papers I've done I've looked at the advance notice to go with it as I'm doing the questions... at least I hope that's the reason!

    Good luck everyone!
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    (Original post by Toshiya)
    Ooh yeah, I wouldn't mind those either...
    Looking over the January 2011 paper, the stuff I don't think is likely to come up is explaining how ID-ID bonds or H bonds form... there was a huge 7-marker on that and solubility of polymers.
    There was a massive question on ozone in the troposphere as well, so I'm hoping that doesn't come up, since I always get my wording muddled trying to explain that!

    I hope I do alright on the advance notice stuff, looking at past papers I seem to trip up mainly on the questions to do with advance notice... that's maybe because on all the past papers I've done I've looked at the advance notice to go with it as I'm doing the questions... at least I hope that's the reason!

    Good luck everyone!
    Luckily enough I don't think the advanced notice is that critical, just seems like it's stimulus material for them to ask storyline questions. Which is worrying because PR doesn't have much storylines!
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    (Original post by gozatron)
    Luckily enough I don't think the advanced notice is that critical, just seems like it's stimulus material for them to ask storyline questions. Which is worrying because PR doesn't have much storylines!
    I don't think it is either, I think it's quite a nice advanced notice for us actually, seeing some of the past ones this one seems nicer.
    Since PR is the smallest chapter they're more limited with the stuff they can ask us... it's seeming fairly easy to predict the questions they can ask. Which is ok with me!
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    (Original post by bertiejess)
    I think that this would just mean thermosets have extensive crosslinks, thermoplastics don't have crosslinks, but i'm not 100% sure
    These are properties of them yes, but the definition is that thermoplastics can be deformed with heating, and thermosets cant.
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    (Original post by Toshiya)
    I don't think it is either, I think it's quite a nice advanced notice for us actually, seeing some of the past ones this one seems nicer.
    Since PR is the smallest chapter they're more limited with the stuff they can ask us... it's seeming fairly easy to predict the questions they can ask. Which is ok with me!
    What are your guesses for what they might ask us? And is it worth me reading the storylines for PR? I bought it but never read it all year!
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    Catalyst notes:

    A pair of reacting molecules must collide, with a combined energy which is greater than the activation enthalpy for the reaction, in order to make a successful collision.
    Catalysts are used in order to overcome the activation energy barrier more easily. Catalysts are used in order to overcome the activation energy barrier more easily. Also successful collisions can take place at a lower energy - this is called lowering the activation energy barrier.

    Catalysts provide an alternative pathway for the breaking and making of bonds. This alternative pathway has a lower activation enthalpy than an uncatalysed pathway.

    Heterogeneous catalysts; the reactants and catalysts are in different physical states.
    They provide a surface on which a reaction may take place; therefore lowering the energy needed for successful collision - this lowers the activation energy barrier.

    Homogeneous catalysts; the reactants and catalysts are in the same physical state.
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    (Original post by icedragon)
    What are your guesses for what they might ask us? And is it worth me reading the storylines for PR? I bought it but never read it all year!
    People have listed loads in this thread, a couple of pages back and someone (Hudzy I think?) made like a revision sheet which is quite handy. The link to that is also a few pages back!

    As for storylines... I haven't used it for revision yet, I've just stuck to my revision guide and it doesn't seem to have done any harm! I only used storylines when my teacher set some work out of it. It's only really useful for the F331 DF module, I found.
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    Typical long-answer mark scheme which are worth memorizing;

    Differences between SiO2 and Co2 (why CO2 is gas and SiO2 a solid, etc)

    SiO2 giant covalent/ network solid/ lattice/ whole structure held
    together by covalent bonds/ correct diagram (1); ignore “giant
    molecule”
    CO2 simple molecular/ molecules/ O=C=O (AW) (1); ignore
    “covalent”
    Comparison of imf: Weaker intermolecular forces in CO2 (can be
    named and can be abbreviated)/ less energy needed to separate
    molecules/ bonds in SiO2 are stronger than CO2 imfs (1)
    mention of imf for SiO2 is CON to third mark

    How the earth is getting warmer/green house gasses

    • Earth emits ir*
    • CO2 absorbs ir*
    • Which causes the bonds to vibrate (more) allow this for other
    radiations absorbed;
    • More CO2 molecules means more radiation is absorbed
    • This is turned into kinetic energy which raises the temperature/
    molecules radiate ir which warms Earth/atmosphere

    How catalysts work


    A catalyst provides (an alternative route for the reaction that has) a
    lower activation enthalpy (1);
    The activation enthalpy is the energy needed for a collision to result in
    a reaction (1); mark separately
    more effective collisions/ more collisions will occur with greater than
    the activation enthalpy/ more successful collisions (1) NOT in context
    of more energy/greater temperature

    how CFC's cause ozone depletion; (and why C-Br doesnt)

    CFCs are not broken down/ unreactive in the troposphere (1);
    CFCs are broken down in the stratosphere (AW) (1);
    by high energy/ frequency uv/ radiation (1);
    producing chlorine atoms/ radicals (1); or equation
    that catalyse ozone breakdown (1) or implied
    plus up to two from:
    C–Br bond is weaker (than C–Cl) (1);
    so can be broken in the troposphere/ molecule reacts in the
    troposphere (1);
    or
    Bromomethane contains C–H bonds that are weaker (than C–Cl) (1);
    so can be broken in the troposphere/ molecule reacts in the
    troposphere (1)

    Effect of temperature on rate of reaction;

    temperature (1) – molecules have more energy/ move faster (1); more collisions with
    energy greater than activation energy (1)
    pressure/concentration (of ozone) (1) – more collisions (1)
    intensity/amount of uv (1) greater amount of radiation breaks more O3 per unit time/
    more photodissociation/ more radicals (1)

    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)
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    (Original post by Toshiya)
    People have listed loads in this thread, a couple of pages back and someone (Hudzy I think?) made like a revision sheet which is quite handy. The link to that is also a few pages back!

    As for storylines... I haven't used it for revision yet, I've just stuck to my revision guide and it doesn't seem to have done any harm! I only used storylines when my teacher set some work out of it. It's only really useful for the F331 DF module, I found.
    Fantastic, thanks!
 
 
 
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