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OCR F324-June 2013 Chemistry

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They're just the halogenation of benzene ones, the electrophilic substitutions.

Btw you laughing at the pacemaker flying out made me laugh

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Revision does this to me. You're a fellow dental applicant aren't you? :biggrin:

I managed to call exam conditions 'standard conditions' last week, and lectured my mum on the harms of too much fat while she was cooking until she eventually kicked me out the kitchen. :redface:

Reply 2301

_HabibaH_

Original post by thers

LOL - I can just imagine it aswell, what a horrible way to die :frown:

I know. I wonder if anyone ever died like that? :confused:

Reply 2302

LegendX

Hi all, can anyone please explain to me whether there is a quick easy way to deduce the molecular formula? Or is it by pure guessing? Also are there any good videos or resources explaining nmr? Thanks

image.jpg465.4KB

Reply 2303

Brad0440

Original post by NilabKebab

Hello, I don't quite understand question 4c in Jan 2012 paper, for the ester the structure was C(CH3)3CH2COOCH2CH3 (check mark scheme) but I got C(CH3)3COOCH2CH2CH3 (Ive attached the molecule I got).

Why is my structure wrong?

Attachment not found

It's wrong because the NMR spectrum tells us that there must be 2 protons attached to the bold C: C-C=O that causes a singlet split (the peak around 2.2)
In your structure, you have the (CH₃)₃C- attached to the C=O, which does not have two hydrogens attached to the bold C in: C-C=O

Reply 2304

Char-

Panic has set in :frown:

So much so, that I've forgotton if we were strongly encouraged or discouraged from highlighting stuff in the questions.
So basically... can we use highlighters? Hahaha.

Reply 2305

hussaincute

nmr jan 2013??? Can somebody explain plz???

Reply 2306

otrivine

Original post by _HabibaH_

I know. I wonder if anyone ever died like that? :confused:

do you know about the M+1? in mass spectrium

Reply 2307

_HabibaH_

Original post by hussaincute

nmr jan 2013??? Can somebody explain plz???

I got that partly wrong so I won't attempt to confuse us both. Sorry.

Reply 2308

thers

Original post by _HabibaH_

I know. I wonder if anyone ever died like that? :confused:

Probably not - I'd imagine all people using MRI would be scanned first to detect for any metal in their body and also check medical history etc.

Reply 2309

hussaincute

guys i have been ill since yesterday so couldn't revise much as i wud have.... Can somebody tell me what should i do now???? :frown:

Reply 2310

Sinkim

Original post by Sly1

What UMS is needed for A,B,C at AS>? Thanks

A-240
B-210
C-180

Same for A2

Reply 2311

LegendX

Original post by hussaincute

guys i have been ill since yesterday so couldn't revise much as i wud have.... Can somebody tell me what should i do now???? :frown:

Revise....

Reply 2312

2013leaver

jan 2013 paper and MS please?

Reply 2313

Sinkim

Original post by Tendael

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.

Sorry, might have made a mistake. Basically if it doesn't dissolve easily it will pass from the column outlet to the detector quicker.

Reply 2314

hussaincute

what should i revise ? :s

Reply 2315

Sinkim

Original post by hussaincute

guys i have been ill since yesterday so couldn't revise much as i wud have.... Can somebody tell me what should i do now???? :frown:

PRAY

Reply 2316

otrivine

Original post by LegendX

Revise....

you know the ratios in NMR spectrium how do we get those

Reply 2317

thers

Original post by hussaincute

guys i have been ill since yesterday so couldn't revise much as i wud have.... Can somebody tell me what should i do now???? :frown:

Go and learn the standard answers from the spec. E.g. comparing kekule and delocalised model etc

Reply 2318

_HabibaH_

Original post by otrivine

do you know about the M+1? in mass spectrium

Gosh, here's me worrying about dead people and you just care about your M+1 peak! :redface:

I don't think we need to know it on our spec but my teacher once explained to me cuz I bugged her about it. and apparently they don't do it on the A level papers anymore cuz it confuses students.

Basically...the peak on the right to the Mr peak is called the M+1 peak (isn't normally showed on our papers). It's because for every 100 or so C-12 isotopes, 1 C-13 isotope is present so this peak represents the presence of that isotope.