Join TSR now and get all your revision questions answeredSign up now
    Offline

    0
    ReputationRep:
    (Original post by Sinkim)
    yes. there is no way you can get 270 from exam alone remember the big one is 150UMS and the small one is 90UMS hence together they add up to around 240 UMS
    What UMS is needed for A,B,C at AS>? Thanks
    Offline

    0
    ReputationRep:
    state the need for deuterated solvents, eg CDCl3, when running an NMR spectrum
    • Thread Starter
    Offline

    2
    ReputationRep:
    (Original post by kuku2013)

    state the need for deuterated solvents, eg CDCl3 when running an NMR spectrum





    when running an NMR spectrum
    not to produce a signal?

    but what is the purpose of this?
    Offline

    0
    ReputationRep:
    describe the use of tetramethylsilane, TMS, as thestandard for chemical shift measurements
    Offline

    0
    ReputationRep:
    describe the identification of O–H and N–H protons by proton exchange using D2O;
    Offline

    0
    ReputationRep:
    alkane solvents them selves would produce a solvent as they are undeuterated ie uneven number of protons however CDCL3 has even number of protons and so the solvent doesnt produce a peak.
    Offline

    0
    ReputationRep:
    (Original post by otrivine)
    not to produce a signal?

    but what is the purpose of this?
    For proton NMR you need your sample in solution for it to work. If you use a solvent it gives rise to peaks. You don't want this as how are you supposed to identify the peaks in the sample?

    So a deuterated solvent is used as it produces no peaks.
    Offline

    0
    ReputationRep:
    (Original post by kuku2013)
    easier said the done though wouldn't you agree?
    Oh definately, but missing out on the a* grade in the course work by one mark is the least important (important still) as long as you do well on f325 and f324 as they have the biggest weightings

    Saying that, the course work is the easiest to pick marks on.
    Offline

    0
    ReputationRep:
    what is the integration trace?
    Offline

    1
    ReputationRep:
    CDCl3 acts as a solvent to dissolve the compound in (so that the NMR works) without interference with the spectrum

    TMS is used as a standard
    Offline

    0
    ReputationRep:
    Someone tell me what ums you need out of 240 for a,b,c grades at as level?
    Offline

    0
    ReputationRep:
    (Original post by kuku2013)
    describe the use of tetramethylsilane, TMS, as thestandard for chemical shift measurements
    TMS chemical shift = 0 and it is used a reference to peaks. Thats all we need to know.
    Offline

    0
    ReputationRep:
    (Original post by Sinkim)
    basically, the GC separate by relative solubility. The more soluble a substance is the quicker it get dissolved hence it is slowed down more.
    But when we talk about relative solubity, don't we always talk about it relative to the stationary phase, but you just said it was less soluble in the mobile phase.
    Offline

    1
    ReputationRep:
    (Original post by kuku2013)
    what is the integration trace?
    Area under each peak to determine relative number of protons
    Offline

    0
    ReputationRep:
    (Original post by Mus1995)
    For proton NMR you need your sample in solution for it to work. If you use a solvent it gives rise to peaks. You don't want this as how are you supposed to identify the peaks in the sample?

    So a deuterated solvent is used as it produces no peaks.
    can you please expand on that I am still confused!!
    Offline

    0
    ReputationRep:
    (Original post by Sly1)
    What UMS is needed for A,B,C at AS>? Thanks
    240 A
    210 B
    180 C
    and 30 downwards per grade
    Offline

    1
    ReputationRep:
    (Original post by kuku2013)
    can you please expand on that I am still confused!!
    You don't need to go into why this is the case. That's probably PHD stuff I'd imagine.
    • Thread Starter
    Offline

    2
    ReputationRep:
    (Original post by Mus1995)
    For proton NMR you need your sample in solution for it to work. If you use a solvent it gives rise to peaks. You don't want this as how are you supposed to identify the peaks in the sample?

    So a deuterated solvent is used as it produces no peaks.
    oh makes sense, but what does deutrated solvent mean?
    Offline

    0
    ReputationRep:
    What are the conditions for alkaline hydrolysis and acid hydrolysis of polypeptides. Also reagents.
    Offline

    0
    ReputationRep:
    (Original post by thers)
    You don't need to go into why this is the case. That's probably PHD stuff I'd imagine.
    that's the problem I don't why it is the case in the first place so need explaining of the basic
 
 
 
Poll
If you won £30,000, which of these would you spend it on?

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

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