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VCE Stuff => VCE Science => VCE Mathematics/Science/Technology => VCE Subjects + Help => VCE Chemistry => Topic started by: Dark Horse on June 09, 2009, 09:01:58 pm

Title: HELP! URGENT!!
Post by: Dark Horse on June 09, 2009, 09:01:58 pm
Hey guys, I was just looking through Stav 08. A question is what will the peaks be split into for the proton NMR of ethylene glycol (OHCH2CH2OH) I said you would get one triplet and one singlet, however, the answers say two singlets. Could someone explain which one is right for the exam tommorow?

Thanks! I really need it :)
Title: Re: HELP! URGENT!!
Post by: d0minicz on June 09, 2009, 09:03:34 pm
becuz the CH2 wont be split by the adjacent OH

theres two singlets
1 for OH
and one for CH2
Title: Re: HELP! URGENT!!
Post by: TrueTears on June 09, 2009, 09:03:53 pm
O shields the H in , no splitting occurs.

H in OH is also shielded by the O, so no splitting occurs.

EDIT: beat me to it d0minicz.
Title: Re: HELP! URGENT!!
Post by: hyperblade01 on June 09, 2009, 09:05:25 pm
Are you getting the triplet from the CH2 next to CH2?
Title: Re: HELP! URGENT!!
Post by: arthurk on June 09, 2009, 09:10:42 pm
adjacent hydrogens in hydrogens from the same environment do not cause splitting to occur as spin spin coupling between them does not occur
i think this was answered in a previous post
Title: Re: HELP! URGENT!!
Post by: Dark Horse on June 09, 2009, 09:39:57 pm
So basically, because both of the CH2s are in an identical chemical environment, they wont cause each other to split?
Title: Re: HELP! URGENT!!
Post by: Dark Horse on June 09, 2009, 09:42:44 pm
so just say in butane : CH3CH2CH2CH3, will the CH2s be split into 6 or 4?
Title: Re: HELP! URGENT!!
Post by: TrueTears on June 09, 2009, 09:45:53 pm
Quote from: Dark Horse on June 09, 2009, 09:39:57 pm
So basically, because both of the CH2s are in an identical chemical environment, they wont cause each other to split?
H's in identical environment do not cause splitting.
Title: Re: HELP! URGENT!!
Post by: arthurk on June 09, 2009, 09:47:28 pm
do we have to know about spin spin coupling anyway?
Title: Re: HELP! URGENT!!
Post by: chem-nerd on June 09, 2009, 09:50:13 pm
Quote from: Dark Horse on June 09, 2009, 09:42:44 pm
so just say in butane : CH3CH2CH2CH3, will the CH2s be split into 6 or 4?

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