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    (Original post by otrivine)
    ok my method

    6=number of carbon atoms
    1= number of double bonds
    3=is the the position of double bond

    therefore,

    hexan-3-oic acid
    very good, nice method
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    (Original post by Zzzyax)
    very good, nice method
    thanks

    Define:stereoisomer

    Describe the steps that takes place in Nucleophilic addition
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    (Original post by otrivine)
    thanks

    Define:stereoisomer

    Describe the steps that takes place in Nucleophilic addition
    1)molecule with same structural formula but different arrangements of atoms with space, cis trans,

    2) generation of the nucleophile, (a dipole being induced or something like NaBH4)

    donation of a lone pair of electrons to the electron deficient carbon atom(or carbon with a positive dipole), which froms a dative covalent bond.

    in aldehydes ketones, the carbon oxygen double bond then breaks leaving a sigma bond, the bondaing pair goes to the oxygen
    which then donates a lone pair to a nearby water molecule or something hcl, forming dative covalent bond finally the oxygen hydrogen bond in water breaks
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    (Original post by Zzzyax)
    1)molecule with same structural formula but different arrangements of atoms with space, cis trans,

    2) generation of the nucleophile, (a dipole being induced or something like NaBH4)

    donation of a lone pair of electrons to the electron deficient carbon atom(or carbon with a positive dipole), which froms a dative covalent bond.

    in aldehydes ketones, the carbon oxygen double bond then breaks leaving a sigma bond, the bondaing pair goes to the oxygen
    which then donates a lone pair to a nearby water molecule or something hcl, forming dative covalent bond finally the oxygen hydrogen bond in water breaks
    Yep and mention that an OH- is released as a product.

    My turn do you have hard question
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    (Original post by otrivine)
    thanks

    Define:stereoisomer

    Describe the steps that takes place in Nucleophilic addition
    Checking your work (quickly) may show that you made a slip.

    - If you're finding the exam hard, chances are the majority of people are too.

    (The honest truth is that you're against the best of the best - someone is likely to do well no matter how harsh the paper is. However you can see for yourself how variable the grade boundaries are, just like any other exam. There is a chance the examiners misjudge the paper and make it too hard.)

    Hey, if England can pull it back against Sweden, so can you

    Best of luck all, no matter what happens it will be fine.
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    (Original post by Zzzyax)
    Checking your work (quickly) may show that you made a slip.

    - If you're finding the exam hard, chances are the majority of people are too.

    (The honest truth is that you're against the best of the best - someone is likely to do well no matter how harsh the paper is. However you can see for yourself how variable the grade boundaries are, just like any other exam. There is a chance the examiners misjudge the paper and make it too hard.)

    Hey, if England can pull it back against Sweden, so can you

    Best of luck all, no matter what happens it will be fine.
    is this message for me or Aishatisha ?
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    (Original post by AishaTara)
    after the nice jan paper, yeah :/
    yeah but did you see how hard f325 paper was? i rekon both units are going to be average tbh!
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    (Original post by otrivine)
    Yep and mention that an OH- is released as a product.

    My turn do you have hard question

    Crystals of glycine melt between 230 - 235 degrees, explain why the melting piont of glycine crystals is higher than that of hydroxyethanioc acid (HOCH2COOH)(mp75-80) [3]
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    (Original post by Craming Revision)
    yeah but did you see how hard f325 paper was? i rekon both units are going to be average tbh!
    no I haven't :/ damn, has anyone got the paper? atleast in june f325 wont be as hard then
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    (Original post by AishaTara)
    no I haven't :/ damn, has anyone got the paper? atleast in june f325 wont be as hard then
    worst paper ever that jan 2013 f325, normally has 1-2 hard questions this one had 4-5 hard questions put everyone off guard, i was onset for an A* got a b wtf lol.
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    (Original post by otrivine)
    ok my method

    6=number of carbon atoms
    1= number of double bonds
    3=is the the position of double bond

    therefore,

    hexan-3-oic acid
    (Original post by Zzzyax)
    very good, nice method
    This would be Hex-3-enoic acid

    Hex -> 6 carbons

    3 en -> double bond on 3rd carbon

    oic acid -> carboxyl group on carbon 1
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    Just realized I need to start re-learning this each night ASAP.
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    (Original post by Craming Revision)
    worst paper ever that jan 2013 f325, normally has 1-2 hard questions this one had 4-5 hard questions put everyone off guard, i was onset for an A* got a b wtf lol.

    What did you get in Unit 4, I got a B with like 80% Raw Marks.

    I wish I did higher, I rushed the whole paper in like 40 minutes. And thought I bossed it.

    Such poor technique. Need like 54+ Raw Marks if I want that A*. Come at me brah
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    Could someone please explain nuclear magnetic resonance?

    Nuclear spin+ resonance + chemical shift please.

    Thanks
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    (Original post by reneetaylor)
    Could someone please explain nuclear magnetic resonance?

    Nuclear spin+ resonance + chemical shift please.

    Thanks
    It states clearly in the spec you don't need to know the details of NMR.

    You just need to be able to understand how to solve related Analysis questions with regards to Proton H+ NMR, and Carbon-13 NMR.

    The only other details are when you have Nitrogen and another element which has a Broad NMR Peak, and the types of Deuterated solvents that you must add to get around this problem. I.e. D20. Then know the limitations and hence the benefits of using NMR and Mass Spec together.

    But the little details won't help you get any Exam Questions right, as its not on the spec.

    Surprised how I remembered all of that. *Pats myself on the back* - must have learnt it pretty well first time round, I'm looking forward to re-learning this now!
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    (Original post by Better)
    It states clearly in the spec you don't need to know the details of NMR.

    You just need to be able to understand how to solve related Analysis questions with regards to Proton H+ NMR, and Carbon-13 NMR.

    The only other details are when you have Nitrogen and another element which has a Broad NMR Peak, and the types of Deuterated solvents that you must add to get around this problem. I.e. D20. Then know the limitations and hence the benefits of using NMR and Mass Spec together.

    But the little details won't help you get any Exam Questions right, as its not on the spec.

    Surprised how I remembered all of that. *Pats myself on the back* - must have learnt it pretty well first time round, I'm looking forward to re-learning this now!
    Haha, I know it's not in the spec and it stated that in the book, I just really still wanted someone to shed some light on to it, just for a more ample understanding, we are expected to know about chemical shift though, says in the examiners tip.

    And to understand that, I feel that I need to understand nuclear spin and resonance. :/

    Wow, this stuff is pretty challenging! :L

    Edit: Thanks for the details about NMR anyway!
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    (Original post by Better)
    What did you get in Unit 4, I got a B with like 80% Raw Marks.

    I wish I did higher, I rushed the whole paper in like 40 minutes. And thought I bossed it.

    Such poor technique. Need like 54+ Raw Marks if I want that A*. Come at me brah
    i got low a in it high boundaries man, but going to do so much better for both units im retaking trying to go for the A* in both modules :/ need to get like 130/150 and for f324 82/90
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    (Original post by reneetaylor)
    Haha, I know it's not in the spec and it stated that in the book, I just really still wanted someone to shed some light on to it, just for a more ample understanding, we are expected to know about chemical shift though, says in the examiners tip.

    And to understand that, I feel that I need to understand nuclear spin and resonance. :/

    Wow, this stuff is pretty challenging! :L
    Yeah this chapter is a bit odd. Don't worry too much about the finite details. To understand NMR Properly you would have to be doing a 1st or 2nd year Physics degree.
    Focus on this and no more: http://www.chemguide.co.uk/analysis/nmr/highres.html

    Edit: I wrote a long ass essay but long story short - you can do it, don't over complicate things, you will learn more from doing questions. Mod 3 is my strongest topic as I realized that there isn't much to learn and its all pretty much logic based. i.e. just lay your work out carefully and follow through methodically
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    (Original post by Craming Revision)
    i got low a in it high boundaries man, but going to do so much better for both units im retaking trying to go for the A* in both modules :/ need to get like 130/150 and for f324 82/90
    Yeah exact same here.

    I will start practicing Mod 4 for like 1 hour each night now because there are so many equations. As long as I finish questions by like Start of May, and start doing timed past papers from like 20 May till the exam hopefully I will score higher.

    But for the rest of the half-term pretty much focusing on my weakest subjects - Phys 5 D1 and C4 -___-
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    (Original post by Better)
    Yeah this chapter is a bit odd. Don't worry too much about the finite details. To understand NMR Properly you would have to be doing a 1st or 2nd year Physics degree. http://teaching.shu.ac.uk/hwb/chemis...lspec/nmr1.htm

    Focus on this and no more: http://www.chemguide.co.uk/analysis/nmr/highres.html

    My strongest topic in Chem 4 is probably Module 3 the resonance stuff, because I realised early on that there isn't actually much to learn in it, and you don't have to be a genius to get the questions right because its just logic based.

    Mod 1 and Mod 2 are more revision ASWELL as practice.

    This time round I will learn Mod 1 and Mod 2 more like I learn Maths, and try to generalise it as much as possible.

    I.e. focus on the fact that Reactions all occur in organic chem because of functional group, which my Tutor last year tried to bang across to me. He told me to stop making it more difficult than it is, because again its A-Level and not university level.

    Apart from some necessary details, you just have to understand the problem solving approach to most questions.
    Thanks, I really needed your common sense and rationale!
    Your advice is really on point, just...hitting the point, right on the point like, right there. BAM.

    Thanks a lot :grin:
 
 
 
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