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OCR Salters Chemistry F335 12th June 2013 Exam revision thread Watch

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    (Original post by thelion0)
    January was fine?
    No, they went up

    June 2012
    A: 63
    B: 56
    C: 50
    D: 44
    E: 38

    Jan 2013:
    A: 71
    B: 64
    C: 57
    D: 51
    E: 45
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    June 2011:

    A - 68
    B- 61
    C- 54

    Three marks difference compared to January 2013. F332 however as I mentioned before really went up with a difference of about 10 marks from the highest its ever been.
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    Hey guys, hope revision is going well for you.
    I've got something that I can't get my head around and it'll be great if could help me

    On p55 in new edition salters revision guide by OCR it says on the top right corner (for visible absorption spectroscopy):
    absorption is more intense and the wavelength of lamda-max increases for organic molecules with large delocalised systems.

    correct me if I'm wrong, but I thought as the delocalisation increases, the excitation energy of electrons would decrease?
    help!
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    Heres a clean F335 Jan 2013 paper if anyone needs it
    Attached Images
  1. File Type: pdf 2013_F335_January.pdf (264.5 KB, 377 views)
  2. File Type: pdf 2013_Markscheme_January_F335.pdf (542.7 KB, 966 views)
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    (Original post by nukethemaly)
    Heres a clean F335 Jan 2013 paper if anyone needs it
    Thanks a lot!
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    Quick question, 2. d) in F335 June 2010 which is here.

    I understand the molecules not getting as close in t-butanol and that this would cause weaker intermolecular bonds, but I'm confused as to why they would both show instantaneous dipole-instantaneous dipole bonding and not hydrogen bonding, they both have alcohol groups. I'm obviously getting something muddled, any help would be appreciated!

    Thanks!
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    (Original post by Salmonidae)
    Quick question, 2. d) in F335 June 2010 which is here.

    I understand the molecules not getting as close in t-butanol and that this would cause weaker intermolecular bonds, but I'm confused as to why they would both show instantaneous dipole-instantaneous dipole bonding and not hydrogen bonding, they both have alcohol groups. I'm obviously getting something muddled, any help would be appreciated!

    Thanks!
    They both have the ability to form two hydrogen bonds (two lones pairs on each oxygen) per molecule so talking about hydrogen bond strength seems redundant in this case. All compounds exhibit ID-ID (some experience additional bonding on top of this) and one compound is more branched so it makes more sense to talk about ID-ID forces here.
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    How is everyone revising?
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    (Original post by Salmonidae)
    Quick question, 2. d) in F335 June 2010 which is here.

    I understand the molecules not getting as close in t-butanol and that this would cause weaker intermolecular bonds, but I'm confused as to why they would both show instantaneous dipole-instantaneous dipole bonding and not hydrogen bonding, they both have alcohol groups. I'm obviously getting something muddled, any help would be appreciated!

    Thanks!
    I think it's mainly due to the fact that the large alkyl groups disrupt the nature of the hydrogen bonding. Because more groups can form idid bonds, hydrogen bonds will not be as effectual.

    Whereas if you have a smaller molecule like ethanol, there's only one alkyl group, so it won't disturb the hydrogen bonding in a carboxylic acid.

    Hope that makes a bit more sense!

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    Hey guys, can someone help me on this question?


    Thallium(I) bromide is insoluble in water. The main reason for this is the small size of the
    negative hydration enthalpy of the Tl + ion. Give two reasons why this value is small.

    Why is the charge density small? I thought larger the charge, smaller the charge density?
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    (Original post by hannahhannah1)
    Hey guys, can someone help me on this question?


    Thallium(I) bromide is insoluble in water. The main reason for this is the small size of the
    negative hydration enthalpy of the Tl + ion. Give two reasons why this value is small.

    Why is the charge density small? I thought larger the charge, smaller the charge density?
    Charge density is a combination of the charge on the ion as well as its size. It has a +1 charge which is quite small anyways but also if you look at its location in the periodic table, it has many electron sub-shells so it's a large ion. This means that in any unit volume, there are lots of these thalium ions so the charge density is small as total charge per unit volume is small. Hope that helped.
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    Hi, does anyone happen to have the mark scheme for the F334 January 2013 paper? I can't find it anywhere..

    Thanks!
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    (Original post by Pandora's Box)
    Hi, does anyone happen to have the mark scheme for the F334 January 2013 paper? I can't find it anywhere..

    Thanks!
    Here!

    I've also attached the paper in case anyone needs it!
    Attached Images
  3. File Type: pdf 2013_F334_January.pdf (344.6 KB, 206 views)
  4. File Type: pdf 2013_Markscheme_January_F334.pdf (95.1 KB, 234 views)
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    (Original post by nukethemaly)
    Here!

    I've also attached the paper in case anyone needs it!
    Brilliant! Thankyou!
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    How's everyone preparing for F335? I'm finding it much harder than all the other modules. I'm thinking about redoing some of the F334 papers for practice as most of the F335 papers are synoptics.
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    (Original post by suncake)
    Nope, we're halfway through Oceans, and starting Medicines by Design after Easter. Saying that, I did my first past paper today and it literally seemed like most of it was just synoptic from either AS or earlier in A2, with only 1 or 2 things we hadn't covered yet. Not sure whether that's a good or bad thing..!

    Posted from TSR Mobile
    As you keep doing the papers, you'll realise that it's all very repetitive and feel even better about it all!
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    (Original post by josephtsui)
    How's everyone preparing for F335? I'm finding it much harder than all the other modules. I'm thinking about redoing some of the F334 papers for practice as most of the F335 papers are synoptics.
    Past papers for sure, you'll get used to how they will ask you, especially in the weird style of "synopticity". I'm kind of lucky (in a sense!) that I'm also doing F332 and F334, so most of prior learning I can slot into F335; but I would recommend reading all your notes from F331 to F334, and doing some past paper questions again.

    You need to have all bases covered for this exam
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    Does anyone know if NaBH4 reduces carboxylic acids to aldehydes?? It just seems logical as it reduces aldehydes and ketones


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    has electrode potential ever shown its face in this exam!? that would be just uncalled for
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    (Original post by Tikara)
    Does anyone know if NaBH4 reduces carboxylic acids to aldehydes?? It just seems logical as it reduces aldehydes and ketones


    Posted from TSR Mobile
    The acidity would decompose the borohydride before its reducing power can be utilized.
 
 
 
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