Hey there! Sign in to join this conversationNew here? Join for free
x Turn on thread page Beta
    Offline

    2
    ReputationRep:
    What parts of the theory side of NMR could come up as a question? (Just wondering which parts to revise)
    Offline

    11
    ReputationRep:
    (Original post by Serine Soul)
    No, just that it uses radiowaves

    So what are the uses of NMR guys?
    And what about GC-MS?
    NMR for MRI scans (came up last year though)
    GC-MS for forensics and space probes on Mars?
    Offline

    18
    (Original post by alow)
    Analysis of compounds.
    In what contexts?
    Offline

    15
    ReputationRep:
    (Original post by itsConnor_)
    Oh ok, I forgot that for hydrolysis. Would it be safe to say '(conc.)' whenever you mention an acid?
    Yeah some require it:
    Reduction of nitro group = conc. HCl
    Nitration of benzene = conc H2SO4
    Esterification with alcohol & carboxylic acid = conc. H2SO4

    Basically the ones where you don't need to say it's in aqueous, is concentrated
    Offline

    18
    (Original post by itsConnor_)
    NMR for MRI scans (came up last year though)
    GC-MS for forensics and space probes on Mars?
    Yep! And GC-MS can also be used for environmental analysis, for pollution and water contamination etc :yes:
    Offline

    15
    ReputationRep:
    (Original post by jerseyalevel)
    What parts of the theory side of NMR could come up as a question? (Just wondering which parts to revise)
    TMS and the solvent CDCl3
    Best to know the structure of TMS as well
    Radiowaves, might want to know about the magnetic spin and why some elements can't be used in NMR
    Offline

    2
    ReputationRep:
    (Original post by tcameron)
    TMS and the solvent CDCl3
    Best to know the structure of TMS as well
    Radiowaves, might want to know about the magnetic spin and why some elements can't be used in NMR
    Great, thanks!
    Offline

    11
    ReputationRep:
    (Original post by jerseyalevel)
    Great, thanks!
    remember TMS is.. the standard for chemical shift measurements
    Offline

    18
    (Original post by itsConnor_)
    remember TMS is.. the standard for chemical shift measurements
    You can also get away with saying 'for calibration' but I'd write both just in case the examiners decide to be mean this year
    Offline

    3
    ReputationRep:
    guys its a pm exam right?


    Posted from TSR Mobile
    Offline

    11
    ReputationRep:
    If they asked to 'state a disadvantage of GC-MS other than that similar structures have very similar retention times', it's unknown compounds have no reference retention times for comparison (wording of specification)
    Offline

    11
    ReputationRep:
    (Original post by ranz)
    guys its a pm exam right?


    Posted from TSR Mobile
    Yes 13:00
    Offline

    0
    ReputationRep:
    Left all my revision until now. I have one day to revise for unit 4. Hopefully i can get at least a D -_-
    Offline

    3
    ReputationRep:
    (Original post by tcameron)
    TMS and the solvent CDCl3
    Best to know the structure of TMS as well
    Radiowaves, might want to know about the magnetic spin and why some elements can't be used in NMR
    why cant some elements be used?


    Posted from TSR Mobile
    Offline

    3
    ReputationRep:
    (Original post by ftsoft2)
    Left all my revision until now. I have one day to revise for unit 4. Hopefully i can get at least a D -_-
    my tip learn reactions and their conditions


    Posted from TSR Mobile
    Offline

    15
    ReputationRep:
    (Original post by ranz)
    why cant some elements be used?


    Posted from TSR Mobile
    if it doesn't have (or have an isotope of) an odd number of nucleons
    Offline

    1
    ReputationRep:
    (Original post by ranz)
    tips for nmr?
    how do u appraoch it?
    Annotate the spectrum that they give you! Think carefully about what the compound is e.g.
    How many proton environments are there? - Integration of 6 = 2 x CH3
    Is there a mess at 7ppm? - Benzene

    I would recommend printing off every NMR question from our spec and just work through them. The only way i figured out NMR is by practice and experience!!
    Offline

    2
    ReputationRep:
    (Original post by danthebox)
    Annotate the spectrum that they give you! Think carefully about what the compound is e.g.
    How many proton environments are there? - Integration of 6 = 2 x CH3
    Is there a mess at 7ppm? - Benzene

    I would recommend printing off every NMR question from our spec and just work through them. The only way i figured out NMR is by practice and experience!!
    You wouldn't happen to have a link to the June 2015 paper would you?
    Offline

    2
    ReputationRep:
    Definition of spin-spin coupling: When the hydrogens attached to on carbon influence the hydrogens on the adjacent carbon atoms. This gives rise to the splitting patterns on the NMR spectrum.
    Offline

    2
    ReputationRep:
    (Original post by yoda123)
    I'm going to do NMR like this
    Peak at 0.8 ppm due to R-CH
    Triplet: adjacent to CH2
    Peak area of 3: CH3
    -CH2CH3
    Same, also when you write out -ch2ch3 circle the proton from the peak you were referring to It makes it much clearer for you when you go back and piece it together.
 
 
 
Reply
Submit reply
Turn on thread page Beta
Updated: September 26, 2016
Poll
Do you like carrot cake?

The Student Room, Get Revising and Marked by Teachers are trading names of The Student Room Group Ltd.

Register Number: 04666380 (England and Wales), VAT No. 806 8067 22 Registered Office: International House, Queens Road, Brighton, BN1 3XE

Write a reply...
Reply
Hide
Reputation gems: You get these gems as you gain rep from other members for making good contributions and giving helpful advice.