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    This exam was seriously not fair! After a whole year of revision getting good grades on past papers and perfecting all the topics I'm probably expecting a damn C after this exam if I'm lucky. If the grade boundaries aren't low aqa have really messed with peoples futures today! 😠
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    (Original post by NobodyCares)
    I think i got around 22 hydrogens, which made the % by mass roughly 9%? (I think the mass of the whole thing was something like 243)
    C6H3(CH3)2-NH-CH2-C(O)-N-(CH3CH2)2 if i remember right which is 22 hydrogens
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    (Original post by blueberry389)
    is the fragment ion same structure as the electrophile?
    i noticed that. Made me stop and think for a bit, but I left it. Seemed to work out?
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    (Original post by Kay Fearn)
    I worked out the Mr of mass in the compund then divided by the Mr of the whole compound x 100

    hope this is right?
    I got the empirical formula then multiplied this by the ratio of (Mr of molecular ion/Mr of empirical formula) which was equal to 2.
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    (Original post by no-1)
    i noticed that. Made me stop and think for a bit, but I left it. Seemed to work out?
    Yeah it was weird they got you to draw the same thing on each page :P
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    I flicked through pages and not seen anyone post...

    In the rate question the last part was aboust propanone being diluted 100x... It asked to design new rate equation

    So from the question it said rate eqn =k {propanone][H+] I think

    So if propanone in huge excess it's pseudo order I think so I put rate =k[h+] is this right? I wasn't sure whether to go with that or r=k[I2][H+]

    Cheers TSR
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    Is anyone making a change.org petition?
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    (Original post by zombaldia)
    I flicked through pages and not seen anyone post...

    In the rate question the last part was aboust propanone being diluted 100x... It asked to design new rate equation

    So from the question it said rate eqn =k {propanone][H+] I think

    So if propanone in huge excess it's pseudo order I think so I put rate =k[h+] is this right? I wasn't sure whether to go with that or r=k[I2][H+]

    Cheers TSR
    This was a dodgy question, I guess it as r=k[I2][H+], what did you put down?
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    (Original post by NobodyCares)
    I think i got around 22 hydrogens, which made the % by mass roughly 9%? (I think the mass of the whole thing was something like 243)
    Ye same something like that
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    (Original post by shiney101)
    This was a dodgy question, I guess it as r=k[I2][H+], what did you put down?
    I put the same as you - it was either that or r=k[H+], but i put that I2 was not in the rate equation before because it was in excess (guessing), so as it is not in excess I put it in
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    (Original post by shiney101)
    This was a dodgy question, I guess it as r=k[I2][H+], what did you put down?
    I wrote exactly the same as the one they gave us.

    k is constant (as temperature is not varied) and I2 is not involved in the rate-determining step so it cannot appear in the rate equation.

    The only things that could affect the rate are concentrations of propanone and protons, which would change.
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    (Original post by Ljm1998)
    Aqa set their A*'s at 90% UMS, and after that the grade boundaries for an A are the total pupils scored below A* and find the 10% then again for BCand D, yet I will make a petition, where should I put it? Change.org? Or Facebook?
    Both
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    (Original post by ishabennett)
    Literally same
    That's exactly how I feel - thought I was on track for an A* but defo not after this
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    (Original post by Ljm1998)
    Aqa set their A*'s at 90% UMS, and after that the grade boundaries for an A are the total pupils scored below A* and find the 10% then again for BCand D, yet I will make a petition, where should I put it? Change.org? Or Facebook?
    Both, but change.org for sure!
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    (Original post by Cadherin)
    I wrote exactly the same as the one they gave us.

    k is constant (as temperature is not varied) and I2 is not involved in the rate-determining step so it cannot appear in the rate equation.

    The only things that could affect the rate are concentrations of propanone and protons, which would change.
    (Original post by NobodyCares)
    I put the same as you - it was either that or r=k[H+], but i put that I2 was not in the rate equation before because it was in excess (guessing), so as it is not in excess I put it in
    (Original post by shiney101)
    This was a dodgy question, I guess it as r=k[I2][H+], what did you put down?
    I agree the question was dodgy because it didn't state I2 wasn't in RDS, it just asked you to suggest why. It could have been that I2 was in massive excess in which case it would appear to be pseudo order. This was a very tricky question I thin.... I think it's safe to say propanone was pseudo order, so would appear to be zero order, but they may still include in rate equation? In which case it'd just be the same? However I think this would be very strange of AQA... I went with r=k[h+] in the end using the logic I2 not in rds and the ketone is in massive excess so won't affect the rate... Hopefully this is right!
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    (Original post by House6797)
    Using AgNO3 is the answer AQA were probably looking for
    however i wrote the same as you and im 99% we are right
    Is this for the acyl chloride and the ketone? I put silver nitrate too, but now I realise that there was a chlorine on both of them so silver nitrate would produce a white ppt with both :/

    Posted from TSR Mobile
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    i got 22 hydrogens but thought the total mass was 220? ended up with 10% as answer
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    (Original post by chem4wasshit)
    i got 22 hydrogens but thought the total mass was 220? ended up with 10% as answer
    I definitely didn't get exactly 10% - I think i got 9.? - not saying you're wrong though
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    I got 23/233
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    (Original post by Cadherin)
    I got the empirical formula then multiplied this by the ratio of (Mr of molecular ion/Mr of empirical formula) which was equal to 2.
    Will you get marks for this way??
 
 
 
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