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Aqa chem 4/ chem 5 june 2016 thread

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Original post by agnessagacious
I wrote that for the last question but it's a tertiary alcohol and it can't be oxidized with potassium dichromate :'( :'(
My answer was a cyclic compound with the diol too! yay
The chloride thing I wrote it's more soluble? idk


it wnt a tertiary alcohol as a tertiary alcohol cant be oxidised, and turning green would show it had been oxidised? I got that structure too
how the **** are we supposed to know what a medical suture is?!! now i know its a stitch that can dissolve so i could answer the question but i didn't know that in the exam did i
I put k[H+] for the new rate equation, if the concentration of propanal is so high so there's a massive excess, it won't limit the rate I think?
Rekt by Chem 4


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9 peaks because of the two methyl groups on the benzene.


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That was terrible would be lucky if i even got a C tbh
Original post by Dizem.Tekin
Please someone say that exam was hard for them too... I started having a panic attack in there... It went horribly and I revised so much for this exam


I was exactly the same revised loads and they go and give us that horrible paper! It was a hard paper. But I kept looking over my calculations and most of them I don't think I could have put anything else.
Original post by Piercedoc21
CH3OCH2CH2C(CH3)2OH
Anyone else with the same


Same mate, 99% sure its correct
The last question rekt me, just couldn't get the structure.


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dnan
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Other than marks 6 marks that i found difficult and know i lost, i though that was a reasonable paper. Did anyone say electrophillic addition for the one where a aldehyde became an ether or just me?
Also my compound for the last question had one alcohol group and one ether group...
rip me
Ok so for the last question we know it has to be a primary/secondary alcohol because of the dichromate reaction, but the O-H nmr peak was a singlet, suggesting the adjacent carbon to the alcohol group is itself bonded to no hydrogens. Therefore how can it be a primary or secondary alcohol??
did people get like 9% for hydrogen percentage of mass
Original post by chloeabeki
I put k[H+] for the new rate equation, if the concentration of propanal is so high so there's a massive excess, it won't limit the rate I think?

I worked with the same logic.
Original post by jakeysimps11
Same mate, 99% sure its correct


It cant be tertiary because that doesnt change colour in acidified potassium dichromate
yes!
Before I forget these are some of my answers, not saying they're right by any means though

ph values were something like 2.08, 2.32, 3.33
for the salt/acid weird question i got 1.20
9.09x10-3 for one question can't rememer which one
9 peaks for the tick box question
Last question I got the structure: CH3-O-C(CH3)2-CH2-CH2-OH
I said the rate would be 100 times bigger but now I figured that there will not probably be enough H+ to react it with so it is limited the the miles of H+. I got it wrong😭😭😭😵😵


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Disgusting paper. 9 marks for that last question was so harsh, I said there's 5 peaks so there must be 5 Hydrogens in different environments, the absorption at X(forgot number) is caused by OH - alcohol

Think i lost 7 marks on it or more :-( I said it was a diol.

For the question about how to obtain alcohol from the reaction mixture I talked about fractional distallation.
For the mark before that I said H2o with conc NaOH, I hope this is right :/

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