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    (Original post by tom108)
    So far, about 9 for me. That will soon change....
    Do you know how many marks you need on this for the grade you want? I don't think I'm in trouble unless I drop below 75% UMS on this exam.
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    (Original post by ManPowa)
    Question 1
    Organic compound: phenyl amine

    Structure: 1,3-dimethly amine

    Condition: temperature below 5 degrees (ice-cold)

    Reaction mechanism: electrophillic substituition

    Witts prediction: Anyone.!

    Why dyes are coloured:
    electron is excited / jumps up energy levels AND (as a result of) light / (UV) radiation / energy / photons
    frequency (absorbed) depends on energy change
    OR (?)E = hv
    dyes / coloured compounds / ‘compounds containing more benzene rings’ (AW) absorb in the visible / absorb light
    plus two from:
    energy levels are closer / energy gap is smaller / excitation energy is smaller when there is: more delocalisation more conjugation more than one benzene ring
    larger chromophore
    (dyes) transmit / reflect (NOT emit) the complementary colour ??



    Explain why benzene undergoes substitution: maintain stability, delocalised electrons keep the benzene ring intact and what else??

    Total : 16 marks
    For witts prediction, I wrote orange is between brown and yellow. and the extent of delocalisation in the dye is between the extent of delocalisation in brown and yellow
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    (Original post by tom108)
    I put temp below 5 and alkali conditions.
    Didnt the two colours mix to from a orange colour?

    For the six marker, that sounds perfect!!

    Other answers i remember writing?

    Ether
    Alkene
    Ringing a COOH
    The reason we add salts,? So that the molecule is soluble in water.

    Can you remmeber Q 2?
    (Original post by jiemanm10)
    thanks for the post could you do this for all the questions please?
    Yep in the process and ive done question 2 aswell.. See below
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    (Original post by ManPowa)

    Comment - If your total entropy was positive, then a fuse will not be required as the reaction is spontaneous. However, if your toral entropy change was negative, then a fuse will be required. I think on the mark scheme, this will be ECF as even if you get the wrong answer but you can still get the mark for the comment.
    With this one I think they wanted us to say the total entropy was positive so it should happen 'spontaneously' but just needs a fuse to start it up due to having a high activation enthalpy [/QUOTE]
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    It's a joke how many marks i lost in this ******* paper :cry2:

    DOES ANYONE HAVE A GUESS FOR WHAT THE GRADE BOUNDARIES WILL BE?????
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    (Original post by ManPowa)
    Yep in the process and ive done question 2 aswell.. See below
    Thank you very much! how can you remember all these questions?!
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    Question 3 - 20 marks

    molecular formula : C8 H8 02

    Equasion: phenylethanoic acid + calcium carbonate >>>> ????

    Curly arrow on the retrosynthetic analysis - From the Ch2 to the CO BOND

    Explain why synthons are not used to make the required compound.

    Nucleophilic substituition : Swap the CN with the Br and then leave the bromine as Br-

    Data sheets reageants : H+/H20/ with reflux

    Predict: As the forward reaction is exothermic, the equilbrium shifts to the left to absorb the heat and counteract the change. The equilibrium constant Kc, shall decrease..

    circled functional group : ether
    Functional in IAA BUT NOT IN THE OTHER TWO : Amine

    Wavenumber : O-H bond at a peak of 2500 - 3200 cm-1

    Circle just the carboxylic acid group.. this is the common pharmacophore in all 3 molecules

    Formula of the salt : someone has previously posted the exact answer

    Suggest why it is converted into a salt : I put to control the soil pH :/ lol and then i added salts are ionic which are water soluble.. Hmm... Answer people ..!!

    2 arguments :
    Inexpensive (cheap), use in small concentrations. anything else.. !!!
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    (Original post by jiemanm10)
    Thank you very much! how can you remember all these questions?!
    I have a ****e memory.. its just that i happen to have the exam in front of me lol
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    (Original post by ManPowa)
    Explain why synthons are not used to make the required compound.
    Because they rarely exist, they're just 'idealised' fragments
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    (Original post by jungdao)
    Flourine is always -1.

    It was 3S + 2CuF2 --> 2CuS + SF4 I think.

    We were told that copper is +2 to start with.

    Sulfur goes from 0 in 3S to +4 in SF4. (oxidation)

    Apparently sulfur also gets reduced: 0 to -2 in CuS.

    I erroneously wrote copper gets reduced from +2 in CuF2 to -4 in CuS >_> now I think of it, copper can't be a -4 ion so both answers were sulfur. In CuS the states are +2 and -2.
    That was a horrible question. There must be so many people (me included) who got that wrong...Only one person I spoke to after the exam got it right.

    Overall though, didn't think it was too bad, not an easy paper, but I've done worse. The easy questions seemed really, really easy and the hard questions really, really hard.
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    (Original post by ManPowa)
    Question 3 - 20 marks

    molecular formula : C8 H8 02

    Equasion: phenylethanoic acid + calcium carbonate >>>> ????

    Curly arrow on the retrosynthetic analysis - From the Ch2 to the CO BOND

    Explain why synthons are not used to make the required compound.

    Nucleophilic substituition : Swap the CN with the Br and then leave the bromine as Br-

    Data sheets reageants : H+/H20/ with reflux

    Predict: As the forward reaction is exothermic, the equilbrium shifts to the left to absorb the heat and counteract the change. The equilibrium constant Kc, shall decrease..

    circled functional group : ether
    Functional in IAA BUT NOT IN THE OTHER TWO : Amine

    Wavenumber : O-H bond at a peak of 2500 - 3200 cm-1

    Circle just the carboxylic acid group.. this is the common pharmacophore in all 3 molecules

    Formula of the salt : someone has previously posted the exact answer

    Suggest why it is converted into a salt : I put to control the soil pH :/ lol and then i added salts are ionic which are water soluble.. Hmm... Answer people ..!!

    2 arguments :
    Inexpensive (cheap), use in small concentrations. anything else.. !!!
    For the wave number one i put c=o at 1750???
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    (Original post by ManPowa)
    I have a ****e memory.. its just that i happen to have the exam in front of me lol
    hey could u please include the marks for each part of the questions. thanks!
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    (Original post by tom108)
    For the wave number one i put c=o at 1750???
    i think it asked for an absorption above 1750
    sorry mate
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    (Original post by dan1993)
    i think it asked for an absorption above 1750
    sorry mate
    I thought it was above 1700cm-1 they said??? (((
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    (Original post by dan1993)
    i think it asked for an absorption above 1750
    sorry mate
    It was above 1700. So that corresponded to the C=O on the carboxylic group
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    It asked above 1700..
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    (Original post by tom108)
    I thought it was above 1700cm-1 they said??? (((
    my bad i could have been over 1700....i just remember 17 something
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    (Original post by dan1993)
    my bad i could have been over 1700....i just remember 17 something
    haha
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    Anyone have an unofficial mark scheme? If you do please let me know thx
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    (Original post by tom108)
    I thought it was above 1700cm-1 they said??? (((
    it was :]
 
 
 
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