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AQA CHEM4 discussion/unofficial mark scheme Watch

  • View Poll Results: How hard did you find this paper?
    Easy, will get an A*
    31
    4.66%
    Moderate
    89
    13.38%
    Harder than any other paper
    405
    60.90%
    I flopped
    140
    21.05%

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    (Original post by SubwayLover1)
    Thankyou so much!

    What other mechanisms were there?? I can't remember at all!
    Electrophilic sub
    Nucleophillic addition

    I think that was it!
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    (Original post by haj101)
    Electrophilic sub
    Nucleophillic addition

    I think that was it!
    Thank-you so much!! You have made me a lot more confident !

    For some reason I remember drawing a mechanism with oxygen involved !

    I wish we could see the paper!
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    could you have CH3COOH + H2O =====> CH3COO- + H30+for the first question?
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    (Original post by SubwayLover1)
    Thank-you so much!! You have made me a lot more confident !

    For some reason I remember drawing a mechanism with oxygen involved !

    I wish we could see the paper!
    No problem
    Same :/ sad times
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    salam, che joori be varaghe emtehani dastresi peyda kardi baad az inke javab ha ro post koni? motmaeni ghabool mishi? man dobare saale bad emtehan midam. kheyli shimim zaeef shode. U chi?thank you reply me back please
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    chejoor inhame javab dadid?
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    (Original post by LearningGeek)
    could you have CH3COOH + H2O =====> CH3COO- + H30+for the first question?
    Yep Thats correct Thats better because it said how ethanoic acid reacts with water thats 100% correct
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    The acid questions are wrong on this marksheme
    who the hell wrote this?!
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    (Original post by SubwayLover1)
    Yep Thats correct Thats better because it said how ethanoic acid reacts with water thats 100% correct
    phew! I was getting worried for a moment, thank you
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    what other Qs were there not mentioned in this ms? thanks
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    My answer for the following question:

    Why is lidocaine hydrochloride used in medicine?

    One NH2 group has been protonated in lidocaine hydrochloride, but neither group has been in lidocaine. This means the lidocaine the molecule is basic due to the two NH2 groups, but lidocaine hydrochloride is neutral, as equal amounts of H+ will dissciate from the NH3+ group as protonate the NH2 group, therefore lidocaine hydrochloride will not change the pH of blood, but lidocaine might?
    Does this answer sound feasible? I have not seen many other answers to this question.
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    (Original post by Kaya22)
    The acid questions are wrong on this marksheme
    who the hell wrote this?!
    why are they wrong? no need to be rude.
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    (Original post by MissVerma)
    CH3 O C(CH3)2 CH2CH2 OH
    That's exactly what quite a few of us got!
    Urgh I was so close but ran out of time I ended up scribbling down CH3OCH2CH2C(CH3)2OH I got my two CH3 groups the other way around to the two CH2's... Just thinking about it though would it matter because it still means both CH3 groups and equal and adjacent to an O as is one of the CH2's... Just the other O???
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    (Original post by Kaya22)
    The acid questions are wrong on this marksheme
    who the hell wrote this?!
    they're right
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    [QUOTE=Medlad101;65816515]they're right[/QUOTE

    ohh on the new one they are, i was looking at the old one with CH3OOH2! silly me!
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    (Original post by logicmaryam)
    Heey guys, I think we can all agree this paper was one of the hardest CHEM4 papers ever.

    Question 9 Notes
    Potassium dichromate turns green, either a primary or secondary alcohol, or aldehyde
    O-H absorption in the Mass spec
    O-H in NMR spectrum, singlet obvs
    CH3-O present in NMR spectrum, singlet
    RCH2 in NMR spectrum, triplet ?
    R(CH3)2 in NMR spectrum, doublet ?
    Omg I got everything apart from the potassium dichromate! Maybe I didn't read the question clearly in a panic. Last 10 mins lol
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    (Original post by AnnieHerbert)
    My answer for the following question:

    Why is lidocaine hydrochloride used in medicine?

    One NH2 group has been protonated in lidocaine hydrochloride, but neither group has been in lidocaine. This means the lidocaine the molecule is basic due to the two NH2 groups, but lidocaine hydrochloride is neutral, as equal amounts of H+ will dissciate from the NH3+ group as protonate the NH2 group, therefore lidocaine hydrochloride will not change the pH of blood, but lidocaine might?
    Does this answer sound feasible? I have not seen many other answers to this question.
    I said after its been protonated it will form an ammonium salt . Ammonium salts are ionic and can dissolve in water which means they can easily be delivered
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    Knew it was LiAlH4, stupidly I said NaBH4 because I felt pressed for time, it was one of the last things I revised!

    Think I've dropped ~10-15 marks being brutally honest, don't care about getting an A* I just want to get an A and enough to help boost up marks that I may have dropped on other papers!
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    For last question I just put all of the structures that would be present due to the spectra, that it would be a primary/secondary alcohol and from the IR spec only no C=O/C=C bonds, then the displayed structure which was CH3OCH2CH2C(CH3)2(OH) - I really don't know what else you could have said/done for that.
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    Hi , I have a question, how did you find all the answers to questions straight away after the exam date? I mean , did your college give you an extra paper and you worked out the paper at home to publish the answers online? I.e will you pass or retake it next year?
 
 
 
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