Hey there! Sign in to join this conversationNew here? Join for free

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

    Offline

    0
    ReputationRep:
    (Original post by BeeJay)
    i knew there was 2 chiral centres, each with 2 isomers hence 4, but how would yu draw then?? it was the way it was drwan that really put me off!
    1) theirs

    2) left the bottom as it was, left hydrogen goign from the top, then swapped the one on the top left and top right.

    3)then swapped the bottom left and bottom right (left hydrogen where it was) and kept the top how they had it the first time.

    4)then had the bottom swapped (like in3) and had the top swapped as it was in 2
    Offline

    0
    ReputationRep:
    (Original post by TwilightKnight)
    Potassium hydroxide is definitely wrong since COO-K+ would be generated in Aspirin and O-K+ would be generated in Paracetamol.

    Im not sure about the Bromine. I remember reading that anything other than Phenol resists Bromination like that due to the Pi-bond delocalisation. Don't quote me on it.
    Oh right thanks
    Offline

    0
    ReputationRep:
    I'm commenting the number of marks that I've lost, then that will suffice and I'm leaving here.
    (I'm not convinced about all of these, but they are possible.)
    2 on NaBH4 (possibly, if what Noble says isn't correct)
    1 on impurity (if what Noble says is correct)
    1 on stupid naming of peptide bond as secondary amine
    2 on saying that halogenoalkane would react with peptide (possibly - nobody seems to know if this would lose marks or not)
    Possibly a further 1 by calling 1,2-dibromocyclohexane 1,2-dibromocycloalkane for some unknown reason (I'm not at all sure whether I actually did this!)

    I stress that these are only possibilities, and I can't honestly remember what I put. Realistically I've lost between 3 and 7+ marks! Not that good really.

    But I think that the grade boundaries will be lower this time than usual - timing was clearly a problem for the majority of people that I've spoken to. Also I think that sometimes OCR awarded too few marks for questions, which in itself caused timing issues - e.g. on the azodye formation one, that's normally worth more than 5; the NMR spectrum wasn't that many marks either; and the phenol-benzene-cyclohexene comparison one.
    Offline

    0
    ReputationRep:
    For the last question, I got:
    A: NaOH (first put dilute HCL then changed it to this)
    B: Ethanol
    C: Ethanoic acid, thought in the heat of the moment that this would react with the -OH group on phenol, then realised afterwards that phenol was itself acidic. Ooops..
    Offline

    0
    ReputationRep:
    (Original post by M_J)
    1) theirs

    2) left the bottom as it was, left hydrogen goign from the top, then swapped the one on the top left and top right.

    3)then swapped the bottom left and bottom right (left hydrogen where it was) and kept the top how they had it the first time.

    4)then had the bottom swapped (like in3) and had the top swapped as it was in 2
    I didn't swap the atoms but the bonds...Like on the one they had given both hydrogens were bonded with a straight line so i changed one to a dashed line and tried to make all the isomers different with the plane they were on. OMG i have so failed. ohh welll
    Offline

    0
    ReputationRep:
    (Original post by BHAM!)
    Was that the bottom right in the corner? I don't remember which one i chose just that it wasn't the top right.
    yh i think it was there..no its wasnt the top one
    Offline

    1
    ReputationRep:
    The Azo dye one annoyed me. They gave a huge honking space to show the structure of the two compounds that form it, and then a diddy few lines to state the reagents, conditions and steps.

    I just wrote it as as a 3 part equation, wrote the reagents and conditions, and wrote "see equation".

    They usually accept equations, so meh.
    Offline

    0
    ReputationRep:
    For reagent A i said NaOH as it reacts with OH and COOH group in both compounds to make a salt.

    For reagent B i said NaBH4 as it would reduce the COOH to OH but wouldn't with the other compound.

    For reagent C i said Phenylamine...but then realised this would not be the only reagent to make an azo dye... FAIL!

    So, i think my first two are ok?
    But the last one must be wrong! ahh well..
    Offline

    0
    ReputationRep:
    (Original post by BHAM!)
    I didn't swap the atoms but the bonds...Like on the one they had given both hydrogens were bonded with a straight line so i changed one to a dashed line and tried to make all the isomers different with the plane they were on. OMG i have so failed. ohh welll
    tbh i'm not even sure if what i did was right anymore. i keep doubting myself now!
    Offline

    1
    ReputationRep:
    guys do you rekon the grade boundaries will be lowered? x
    Offline

    0
    ReputationRep:
    (Original post by The_wise)
    guys do you rekon the grade boundaries will be lowered? x
    Just posted this:
    But I think that the grade boundaries will be lower this time than usual - timing was clearly a problem for the majority of people that I've spoken to. Also I think that sometimes OCR awarded too few marks for questions, which in itself caused timing issues - e.g. on the azodye formation one, that's normally worth more than 5; the NMR spectrum wasn't that many marks either; and the phenol-benzene-cyclohexene comparison one.
    Offline

    2
    ReputationRep:
    (Original post by work now, enjoy later)
    The question about the isoelectric points, what did everyone get? we didnt have to draw the whole amino acid did we?
    well, yeah enough to show all the NH2 COOH groups, and any changes they undergo
    Offline

    1
    ReputationRep:
    guys what were the three amino acids for that isoelctric question? x
    Offline

    1
    ReputationRep:
    guys can you remember the three amino acids for that isoelctric point question?? x
    Offline

    0
    ReputationRep:
    (Original post by M_J)
    1) theirs

    2) left the bottom as it was, left hydrogen goign from the top, then swapped the one on the top left and top right.

    3)then swapped the bottom left and bottom right (left hydrogen where it was) and kept the top how they had it the first time.

    4)then had the bottom swapped (like in3) and had the top swapped as it was in 2
    ohhhh cheers daaammmn!!
    Offline

    1
    ReputationRep:
    anyone got the paper?
    Offline

    2
    ReputationRep:
    (Original post by The_wise)
    guys what were the three amino acids for that isoelctric question? x
    glycine, glutamic acid and lysine?
    i dont remember lol
    Offline

    0
    ReputationRep:
    For the last question I got totally confused and wrote NaOH and H2SO4 for the reagents of B and C as I thought the ester bond would have been hydrolysed by the alkali and the amide bond would have been hydrolysed by the acid. FML. Any chance it could also be right.
    Offline

    1
    ReputationRep:
    (Original post by JordanCarroll)
    glycine, glutamic acid and lysine?
    i dont remember lol
    yh i thnk thats right but was the acid for it when it asked u to draw a zwitterion and what was the amin acid for PH10 and PH 2?
    Offline

    1
    ReputationRep:
    what amino acid was it for the zwitterion question?!!!im desperate to know!!
 
 
 
  • See more of what you like on The Student Room

    You can personalise what you see on TSR. Tell us a little about yourself to get started.

  • Poll
    Has a teacher ever helped you cheat?
  • See more of what you like on The Student Room

    You can personalise what you see on TSR. Tell us a little about yourself to get started.

  • The Student Room, Get Revising and Marked by Teachers are trading names of The Student Room Group Ltd.

    Register Number: 04666380 (England and Wales), VAT No. 806 8067 22 Registered Office: International House, Queens Road, Brighton, BN1 3XE

    Write a reply...
    Reply
    Hide
    Reputation gems: You get these gems as you gain rep from other members for making good contributions and giving helpful advice.