The Student Room Group

OCR A2 CHEMISTRY F324 and F325- 14th and 22nd June 2016- OFFICIAL THREAD

Scroll to see replies

Reply 1380
Avatar for ranz
ranz
5
Original post by ReeceM1
6 proton environments, it's just that on an NMR spectrum the 3 benzene environments will appear as one messy peak.


ah okk cool i was confused as th spectrum had 4 peaks only


Posted from TSR Mobile
i thought we are answering carbon environments
Original post by alow
Do you know what "multiplet" means? The benzene has 3 environments, each of which will produce probably doublets or triplets, depending on the resolution of the NMR.


But OCR counts all of the benzene Hs as one environment. And integrates them all together. So you won't see doublets or triplets. Just a multiplet. With an integration of 5H
Original post by alow
The 3 environments would be fairly distinct and assignable, especially on the BS spectra they give you at A Level.


agree the spectra is stupid
Original post by alow
The 3 environments would be fairly distinct and assignable, especially on the BS spectra they give you at A Level.


Sorry but please don't stress me out the night before the exam unnecessarily...in proton NMR for benzene rings we only look at one splitting pattern right......? :frown:
Reply 1385
Avatar for alow
alow
19
Original post by Chem1stry101
But OCR counts all of the benzene Hs as one environment. And integrates them all together. So you won't see doublets or triplets. Just a multiplet. With an integration of 5H


Just because they're all integrated together doesn't mean you can't assign them. You can see the splitting.
Reply 1386
Avatar for alow
alow
19
Original post by itsConnor_
Sorry but please don't stress me out the night before the exam unnecessarily...in proton NMR for benzene rings we only look at one splitting pattern right......? :frown:


I assigned them all when I did F324.
Original post by alow
I assigned them all when I did F324.


so why wouldn't I be taughtt this and why is it alien to me????????????????????????
has anyone got the markscheme for f324 june 15 ???
Reply 1389
Avatar for alow
alow
19
Original post by itsConnor_
so why wouldn't I be taughtt this and why is it alien to me????????????????????????


I don't know if I was taught it but I did it, because it's the correct way.
Will alcohol + Na -> o- na+?
Original post by itsConnor_
Sorry but please don't stress me out the night before the exam unnecessarily...in proton NMR for benzene rings we only look at one splitting pattern right......? :frown:


For benzene you will just look for a (usually) messy signal at around 7ppm. It's unlikely you will be able to see the different benzene H environments in that area. Just look for the integration to find out how many times the ring is substituted.
Original post by alow
I don't know if I was taught it but I did it, because it's the correct way.


https://gyazo.com/4466d9845c0fed137c580d4085972d86

how are they "fairly distinct and assignable" ? :frown:
Original post by alow
I assigned them all when I did F324.


It's not necessary and doesn't feature in any F324 mark schemes.
Reply 1394
Avatar for alow
alow
19
Original post by itsConnor_
https://gyazo.com/4466d9845c0fed137c580d4085972d86

how are they "fairly distinct and assignable" ? :frown:


Looks like a doublet on the RHS, a triplet slightly left of centre and something else overlapped with them.
Reply 1395
Avatar for alow
alow
19
Original post by Chem1stry101
It's not necessary and doesn't feature in any F324 mark schemes.


I never said it did, but it is correct.
Original post by alow
Looks like a doublet on the RHS, a triplet slightly left of centre and something else overlapped with them.


If you want to show off, please do it elsewhere because I am getting seriously stressed out now!
Original post by itsConnor_
https://gyazo.com/4466d9845c0fed137c580d4085972d86

how are they "fairly distinct and assignable" ? :frown:


They're not. And any F324 mark scheme will just expect to state 5H on a benzene ring
Original post by alow
I don't know if I was taught it but I did it, because it's the correct way.


so for this compound here,

the aromatic proton splitting would be doublets for 10,11,4,5 each with 1H and singlet for 2 with 1H.
(edited 7 years ago)
Original post by Chem1stry101
They're not. And any F324 mark scheme will just expect to state 5H on a benzene ring


Thank you. Going to need to check things with my teacher tomorrow as alow has given me a panic attack! :s-smilie:

Quick Reply

Related discussions

Latest

Trending

Trending

Articles for you