OCR Chemistry A F324 Rings, Polymers and Analysis Tue 19 June 2012

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I don't think that it matters on the last mechanism whether or not you do use R or Li, as long as you get that the R group attacks the C atom causing the Oxygen double bond to break leaving it ^-, then a water molecule in the intermediate stage donating a H^+

Dont forget the dipoles on the C and O. You didnt need to include the water in the intermediate the arrow going to the final product said H+/H2O

Reply 1781

racheatworld

Original post by Gman1234

Dont forget the dipoles on the C and O. You didnt need to include the water in the intermediate the arrow going to the final product said H+/H2O

Totally agree with you. No water needed in intermediate stage.

Reply 1782

LiveOne

Original post by Gman1234

Dont forget the dipoles on the C and O. You didnt need to include the water in the intermediate the arrow going to the final product said H+/H2O

oh good I was getting worried for a minute there that I needed to have drawn the water! But I'm sure they only asked for the organic intermediate

Reply 1783

holahola

Original post by Gman1234

Dont forget the dipoles on the C and O. You didnt need to include the water in the intermediate the arrow going to the final product said H+/H2O

what if you did fo the water. would you loose a mark

Reply 1784

SpringNicht

People are saying they did the steroid one the wrong way round, which way was it meant to be? :s-smilie:

Worried...

Reply 1785

DarkPeople

Original post by racheatworld

I'm not talking about H NMR, I was talking about the C13 NMR which was on the first page? It was definitely a C13 NMR.

Ahh right. I remember now. Wasn't it something like 6 C environments?

Reply 1786

Gman1234

Original post by holahola

what if you did fo the water. would you loose a mark

As long as you have the intermediate correct, I would have thought not.

Reply 1787

Educator

i thought it was nuleophilic addition ?!?!?
OMG can't believe it was electrophilic :frown:

Reply 1788

rasklatz

27 carbons and 8 chiral anyone ?

Reply 1789

windo

what do everyone think the grade boundaries will be for.....

A -
B -
C -
D -
E -

????

Reply 1790

LiveOne

Original post by holahola

what if you did fo the water. would you loose a mark

normally they just have 'ignore' in the mark scheme, so I doubt it

Reply 1791

niaghez

would it be right if i put use a gas chromatogram using the peaks for the mark for how to find out abundances and stuff of the esters?

Reply 1792

Dollyandra

How many chiral carbons were there in the 1 mark Q?
I put 7 but I was told by some mysterious boy on the bus it was 1.
Could anyone explain? Thank you

Reply 1793

Nerdatious

Original post by rasklatz

27 carbons and 8 chiral anyone ?

That's what I got!

Reply 1794

Aa234

Original post by SpringNicht

People are saying they did the steroid one the wrong way round, which way was it meant to be? :s-smilie:

Worried...

You had to reduce first

This was posted from The Student Room's iPhone/iPad App

Reply 1795

racheatworld

Original post by DarkPeople

Ahh right. I remember now. Wasn't it something like 6 C environments?

Yes 6 seems to be the general consensus.

Reply 1796

Gman1234

A - 47
b - 42
c - 37
d - 32
e - 27

Reply 1797

DarkPeople

Original post by rasklatz

27 carbons and 8 chiral anyone ?

Yeah I got that (y)

Reply 1798

Fww

The equation for the mechanism on question four was:

HNO3 +H2SO4 -------> NO2^+ + HSO4^- + H20

Then after the drawing you needed to show how the sulphuric acid acted as a catalyst

H^+ + HSO4^- -------> H2SO4

The H^+ is the hydrogen ion removed from the mechanism.