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    (Original post by ranz)
    ive accepted that i wont be able to finish nmr correctly, every single past paper ive done i somehow manage to screw up the final structure! i just dont know how to add them together! like a puzzle 😭😭


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    Don't panic in the exam, remember you can get most of the marks without a correct structure
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    (Original post by ranz)
    guys does this have any significance:

    "in the proton nmr spectrum, the peak at xx would normally be expected at a chemical ahift value about e right" what does this mean?


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    Look at the splitting pattern and then refer to the chemical shift in the data sheet ONE to the right (e.g. if 3.4 on spectrum, look at 2.4 in data sheet) i think
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    (Original post by ranz)
    guys does this have any significance:

    "in the proton nmr spectrum, the peak at xx would normally be expected at a chemical ahift value about e right" what does this mean?


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    Assume the chemical shift is at where it indicates.
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    (Original post by itsConnor_)
    Sorry where is the presentation?
    It's from https://www.cpdhub.ocr.org.uk/ which requires a (free) registration, however I've also uploaded a copy here: https://my.mixtape.moe/gfofsl.pdf
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    (Original post by suibster)
    Assume the chemical shift is at where it indicates.
    so if theres a peak at 2 then i should assume they mean at 1 ppm?


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    (Original post by marioman)
    It's from https://www.cpdhub.ocr.org.uk/ which requires a (free) registration, however I've also uploaded a copy here: https://my.mixtape.moe/gfofsl.pdf
    WOW thanks so much
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    (Original post by ImNervous)
    I think the height of the peak at 122 m/e would be greater as it does not contain the isotope so is more abundant? Not really sure though

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    I believe the answer is 1:1 so not sure..
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    (Original post by AqsaMx)
    I believe the answer is 1:1 so not sure..
    i dont think we need to know this though? or am i wrong


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    (Original post by ranz)
    i dont think we need to know this though? or am i wrong


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    It's to do with fragments ( mass spec) and its synoptic from as I believe
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    guys if theres an aldehyde for example, would there be a peak at both 9.5 ppm ( -CHO) and 3.5 ppm (HC-O) for thr aldehyde


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    (Original post by itsConnor_)
    But surely if stationary phase is solid, it separates by adsorption and if the stationary phase is a liquid, it separates by relative solubilities?
    (Original post by AqsaMx)
    I don't have the paper, it was given to me as a pack but the answer was adsorption..
    If the stationary phase is liquid, then the separation occurs by relative solubility.
    If the stationary phase is a solid, then the separation occurs by adsorption
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    (Original post by RayMasterio)
    If the stationary phase is liquid, then the separation occurs by relative solubility.
    If the stationary phase is a solid, then the separation occurs by adsorption
    isnt gc always relative solubility and tlc adsorption?


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    (Original post by ranz)
    isnt gc always relative solubility and tlc adsorption?


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    If the stationary phase in GC is a liquid, then the separation is done by relative solubility. If it was a solid, then it will be adsorption
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    With NMR I go like this...

    Let's just say

    Triplet peak at 0.8ppm with peak area of 2 shows 2xH in CH2, adjacent to CH2

    And do the same for every peak in the spectra...

    Isn't that just as fine?
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    (Original post by Serine Soul)
    With NMR I go like this...

    Let's just say

    Triplet peak at 0.8ppm with peak area of 2 shows 2xH in CH2, adjacent to CH2

    And do the same for every peak in the spectra...

    Isn't that just as fine?
    That's fine. There's no specific format that you must follow, as long as you put the info in you will get the marks!
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    (Original post by ranz)
    guys if theres an aldehyde for example, would there be a peak at both 9.5 ppm ( -CHO) and 3.5 ppm (HC-O) for thr aldehyde


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    No...
    Aldehydes consist of C=O bonds, not C-O bonds, so only a peak between 9 - 10 ppm, and 2-3 ppm if there's another CH attached to the C in C=O
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    (Original post by marioman)
    That's fine. There's no specific format that you must follow, as long as you put the info in you will get the marks!
    Yeah, the table looks really tidy though! (I'm a messy person) just wish I had been told to use it earlier
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    (Original post by Serine Soul)
    No...
    Aldehydes consist of C=O bonds, not C-O bonds, so only a peak between 9 - 10 ppm, and 2-3 ppm if there's another CH attached to the C in C=O
    so if theres a carbon attached to the aldehyde it would show up as HC-O 2-3 ppm?


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    can someone please tell me how to approach these questions? the method for them changes everytime and I never get full marks even though these are supposed to be easy marks
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    (Original post by RayMasterio)
    can someone please tell me how to approach these questions? the method for them changes everytime and I never get full marks even though these are supposed to be easy marks
    ( actual yield/ theoretical yield ) x100 = % yield
    and just rearrange to find different parts when needed.



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