OCR F324-June 2013 Chemistry

on page 84

do you want me to describe spin as to how many hydrogens are found adjacent to carbon ato,m

Yeah that's what I was hinting at when I said in proton NMR, sorry if it wasn't too clear


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oh ok sorry

so spin-spin gives the indication of the number of hydrogen atoms adjacent to carbon atoms and there are peaks in which could vary and represent the number of H , examples are singlet,doublet,triplet , quartet or multiplet

singlet=no H adjacent to carbon
doublet= 1 H adjacent to carbon
triplet= 2 H adjacent to Carbon
quartet= 3 H adjacent on carbon
multiplet= 4+ H adjacet to carbon

Correct.


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Why is there different chemcal shift values (1)

To show that there are different chemical environments?


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because of different electronegativty between atoms

my turn

Oh I see and this will be the last from me, need to do a Maths paper under times conditions

Ethyl Methanoate is one of the compounds responsible for the smell of raspberries. Outline, with reaction conditions, how it could be synthesised in the lab from Methanol. (7)


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Firstly, methanol is a primary alcohol and is therefore, oxidised to a carboxylic acid via heating under relux, with acidified potassium dichromate and concentrated H2SO4 and forms methaoic acid, the methanoic acid then has to react with an alochol and a catalyst would be needed in this concentratied H2SO4 (H+(aq)) and should be heated in a water bath. Methanoic acid reacts with ethanol and undergoes a condensation reaction in which a molecule of water is removed and water would be formed as product. This causes them to join together and forms an ester which is Ethyl Methanoate and this gives rise to the smell of rasberries.

N.B when potassium dichromate is acifiied oxidised colour changes from organe to green

Are you breaking up with me

I thought we were good buddies

Correct.


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Ha. No! You probably just didn't see my question.

oh ok

1) explain why triglycerides are soluble in non polar solvents and not in water [3]

Triglycerides are long chain carbon bonds and atoms and contains no OH group for it to dissolve in water as hydrogen bonds are not formed

Hey people, Im wondering if anyone has got a big compilation of questions? Especially those on the old spec which are still relevant. If people dont mind posing one it could be very useful?

Master Yi posted a link before http://www.thestudentroom.co.uk/showthread.php?t=2281592&page=11&p=42165206#post42165206