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    (Original post by emah123)
    i got 48/60 which shouldve been an A but the grade boundaries were higher for an A for that paper so got 68 UMS what about you?

    do you think i'll be ok?
    Lol I got a D so you should be fine
    I didnt revise at all for this paper because I planned everything really stupidly and wanted to get a high grade in biology so I didnt have to retake it ..... BAD IDEA.
    But yeah, just work hard for the remaining weeks
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    (Original post by Gulzar)
    Lol I got a D so you should be fine
    I didnt revise at all for this paper because I planned everything really stupidly and wanted to get a high grade in biology so I didnt have to retake it ..... BAD IDEA.
    But yeah, just work hard for the remaining weeks
    haha well im also retaking aqa biol4 as well!! so im worse off than you how did you do in biol4 i also got a B
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    (Original post by emah123)
    haha well im also retaking aqa biol4 as well!! so im worse off than you how did you do in biol4 i also got a B
    I got just an A in Biol 4 so now need a mid B in biol 5 to get an A. How r u finding biol 5?
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    Iv have just started revision now lol, can anybody plz tell me how chromatography works because the book doesnt even explain it properly. also do we need to know how thin layer and gas chromtography are carried out??????????
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    Anybody want to do some questions?


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    What sort of marks have people got for june 2012... i found this the hardest paper
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    This offer is subject to you obtaining

    GCE A level
    Grades AAB
    including
    Mathematics

    excluding General Studies

    i know this is a off topic question but does this offer mean that of the 2 A's one must be in maths or does it mean that i can get a B in maths and and an A in my other subjects which are human bio and chemistry.
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    (Original post by otrivine)
    pi bonds are sited above and below the plane of the carbon atoms so 3
    Lets do questions on the first section so benzenes and phenols
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    Hi could someone help me with these two OCR Chemistry F324 questions that i have:

    Q1.) When HOCH2CHO reacts with tollens reagent HOCH2COOH is produced not HOOCCOOH. Why ? Is tollens reagent only strong enough to oxidise aldehyde to carboxylic acid not alcohol to carboxylic acid?

    Q2.) Propan-1,2,3-triol and C17H31COOH react to produce triglyceride. Deduce the number of carbon double bonds in the molecule of the triglyceride.

    Answer is 6. But how is this worked out?


    Thanks
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    (Original post by medicdreamer)
    Hi could someone help me with these two OCR Chemistry F324 questions that i have:

    Q1.) When HOCH2CHO reacts with tollens reagent HOCH2COOH is produced not HOOCCOOH. Why ? Is tollens reagent only strong enough to oxidise aldehyde to carboxylic acid not alcohol to carboxylic acid?

    Q2.) Propan-1,2,3-triol and C17H31COOH react to produce triglyceride. Deduce the number of carbon double bonds in the molecule of the triglyceride.

    Answer is 6. But how is this worked out?


    Thanks
    Q1: Yeah Tollen's reagent is only a weak oxidising agent so can ONLY oxidise aldehydes to carboxylic acids.
    Q2: Sorry I'm not 100% sure but I think because if you have 17 Carbons, you should have 2x17 (34) Hydrogens attached because it's CH2 present in the long chain hydrocarbon part of the carboxylic acid. But since there's only 31 hydrogens that's 3 short so 6 double bonds present... (although I still don't know why it's 6 LOL)
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    (Original post by junaid_k17)
    This offer is subject to you obtaining

    GCE A level
    Grades AAB
    including
    Mathematics

    excluding General Studies

    i know this is a off topic question but does this offer mean that of the 2 A's one must be in maths or does it mean that i can get a B in maths and and an A in my other subjects which are human bio and chemistry.
    Pretty sure it just means Maths should be a subject you're taking lol so you just need an A or a B in it?
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    Can someone explain how you work out the number of different carbon or proton environments in a compound I seriously have no idea this is so frustrating D;
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    Guys am I right in saying that NaBH4 DOES NOT reduce carboxylic acids and esters and only reduces the aldehydes/ketones? If so why is that?
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    (Original post by Gulzar)
    Guys am I right in saying that NaBH4 DOES NOT reduce carboxylic acids and esters and only reduces the aldehydes/ketones? If so why is that?
    I don't think its something you need to know and its not on the specification or in the book so you shouldn't need to learn it. But from what I know carboxylic acids can be reduced. Not sure about esters, I don't think they can though.

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    (Original post by Sarangtaec)
    Can someone explain how you work out the number of different carbon or proton environments in a compound I seriously have no idea this is so frustrating D;
    Carbon is simpler than proton, for carbon just count the number of carbons. It gets a little more tricky when there are equivalent carbons but just remember that they only show as 1 peak, for example Cl-CH2-CH(CH3)CH2CH3 would have 5 peaks but Cl-CH2-CH2-CH(CH3)2 would have 4 peaks as the last 2 methyl groups are equivalent (essentially they are bonded to the same thing)

    Proton is a similar idea, just look at the hydrogen environment, all the hydrogen's in a CH3 are equivalent so they show up as one peak as they dont split each other.
    If you have CH3-CH2 then the first methyl would be a triplet (n+1) rule and the second carbon would be a quartet.

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    (Original post by Sarangtaec)
    Pretty sure it just means Maths should be a subject you're taking lol so you just need an A or a B in it?
    i dnt really knw becoz i thought i needed an A maths, but it just looks highly unlikely becoz i have to get 3 A* in my last 3 units.
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    (Original post by D4rth)
    I don't think its something you need to know and its not on the specification or in the book so you shouldn't need to learn it. But from what I know carboxylic acids can be reduced. Not sure about esters, I don't think they can though.

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    Ok thats fine, thanks.
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    (Original post by D4rth)
    Carbon is simpler than proton, for carbon just count the number of carbons. It gets a little more tricky when there are equivalent carbons but just remember that they only show as 1 peak, for example Cl-CH2-CH(CH3)CH2CH3 would have 5 peaks but Cl-CH2-CH2-CH(CH3)2 would have 4 peaks as the last 2 methyl groups are equivalent (essentially they are bonded to the same thing)

    Proton is a similar idea, just look at the hydrogen environment, all the hydrogen's in a CH3 are equivalent so they show up as one peak as they dont split each other.
    If you have CH3-CH2 then the first methyl would be a triplet (n+1) rule and the second carbon would be a quartet.

    Posted from TSR Mobile
    If I used your example of Cl-CH2-CH(CH3)CH2CH3, where did the 5 environments come from? Does the methyl bonded to CH count as the same as the CH3 at the end? And there are 2 CH2s so are they different or the same? I got Carbon environments: C-Cl, -CH2-, CH... and then I'm lost LOL sorry I'm just so confused >_< I'm ok with the splitting patterns though I just hate identifying number of C/H environments -.-
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    (Original post by Gulzar)
    I got just an A in Biol 4 so now need a mid B in biol 5 to get an A. How r u finding biol 5?
    I don't do Biology but keep in mind when things get moderated they can get taken down 3-5 marks.
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    (Original post by Sarangtaec)
    If I used your example of Cl-CH2-CH(CH3)CH2CH3, where did the 5 environments come from? Does the methyl bonded to CH count as the same as the CH3 at the end? And there are 2 CH2s so are they different or the same? I got Carbon environments: C-Cl, -CH2-, CH... and then I'm lost LOL sorry I'm just so confused >_< I'm ok with the splitting patterns though I just hate identifying number of C/H environments -.-
    I'll write it down and show you tomorrow as it'll be easier than typing it all out.

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