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POST-EXAM CHAT: OCR Chemistry- Rings, Polymers and Analysis - F324 thread watch

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    could you not write ester for asprin and amide for paracetamol????
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    For the last question I put:
    Reagent A: NaOH produce salt of carboxylate and phenolic salt
    Reagent B: KOH - reactive metal reacts with COOH functional group in asprin
    Reagent C: Br2 again - only reaction i could think of with phenol at the time :|
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    One hour was NOT enough time, I made silly mistakes through frantic rushing
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    (Original post by adzharmer)
    Surely phenol isnt the group.... its a molecule... COOH is a group (cant form on its own), OH the same, NH2 the same... phenol can form on its own so surely its just a benzene ring with an alcohol func group, no?
    Phenol is a group and a molecule.

    You can have a phenol group of "benzene-OH" on bigger molescules.
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    (Original post by TwilightKnight)
    There was a similiar question on one of the old papers I did and it said "phenol (allow benzene ring + hydroxyl/alcohol) so you might be alright.
    Yay! Thankyou, you've reassured me a bit.
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    possible retake for the summer
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    "Reagent B: KOH - reactive metal reacts with COOH functional group in asprin"

    Wouldn't a hydroxide/ alkali/ earth metal also react with the OH? It does in phenol.

    Ie. C6H5OH + NaOh -> C6H5O-Na+ + H2O
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    That NMR question was hard normally they 'lead' you to the answer, I got the right ester but my reasoning was F*ucked up. 3/6 for that one
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    can some one explain how you would actully fraw thoses isomers and the anhydride question
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    (Original post by TwilightKnight)
    There was a similiar question on one of the old papers I did and it said "phenol (allow benzene ring + hydroxyl/alcohol) so you might be alright.
    I didn't put benzene ring
    Just put alcohol, at least 1 mark lost atm.
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    (Original post by TwilightKnight)
    Wouldn't a hydroxide/ alkali/ earth metal also react with the OH? It does in phenol.

    Ie. C6H5OH + NaOh -> C6H5O-Na+ + H2O
    Yes it would, that's why it was easier to just put H2O as the reagent. NaOH isn't really the reagent anyway.
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    (Original post by monkey01)
    can some one explain how you would actully fraw thoses isomers and the anhydride question
    Since it has two chiral carbons, it has 2^2 isomers. What you needed to do was first draw the mirror image of the one given. Then draw a 3D structure taking into account rotation of the C-C single bond, showing the CH3 and COOH on the opposite sides; then finally draw the mirror image of that.
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    is anyone going to make an unoffical marksheme pleaseeeeeeeeeeeee
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    oo loool
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    im a bit pissed of with this exam if i am honest. alot of people on here saying it was ok though. i need and A in chemistry for part of my offer and this has probably not helped towards getting it. looking back i dont feel as bad as i did when i just got out of the exam room. what realy got me down was the fact they had that question on the anhydride and in the book theres a paragraph on it and thats it. it doesnt make sense to me when exam boards do this. so im pretty annoyed atm. the first half of the paper i was so confident and was realy going through it fast but then the second half i found horrible. the worst bit is that i think 99% i got the right ester but i worded it so wrong and theres scribbles and stuff all over the place. rant over.
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    (Original post by Noble.)
    Yes it would, that's why it was easier to just put H2O as the reagent. NaOH isn't really the reagent anyway.
    Well, it is there, since it's forming a phenoxide salt with the NaOH, since Phenol is C6H5O- in water, it's an acid-base neutralisation. In the full reaction, water would probably be considered the catalyst there.
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    [QUOTE]i think it was summat like (CH3)2CHCOOCH3[QUOTE]

    Thanks that what I put but for some reason I crossed it out when I panicked at the end!!
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    (Original post by _Andrew_)
    Personally, I found that the most hideous chemistry paper ever :cry2:

    For the last question my reagents where, in this order:

    Naoh - as the both contain acid groups
    LiAl4 in dry ether - as the carboxylic acid group can be reduced back to an alcohol
    Br2 - Another phenol functionall group which activates the ring
    I put the same except NaBH4 to reduce the COOH group
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    (Original post by monkey01)
    is anyone going to make an unoffical marksheme pleaseeeeeeeeeeeee
    Yer, can someone please please put up a markscheme???
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    (Original post by Noble.)
    Yes it would, that's why it was easier to just put H2O as the reagent. NaOH isn't really the reagent anyway.
    Was H20 the reagent for A? I think that's what I put.
 
 
 
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