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Aqa chem 4/ chem 5 june 2016 thread

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Why is there still no facebook page or something else to pressurise AQA :cry2:
Original post by BeckaH2
Why is there still no facebook page or something else to pressurise AQA :cry2:


https://www.facebook.com/groups/148389988911787/
Original post by thomaarrss
did people get like 9% for hydrogen percentage of mass


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?
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?


yh... there were 13-14 hydrogens right??
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ELCRE
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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 just didn't know how to do that question in the exam, I didn't have time to think even think about it :frown:


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https://youtu.be/cuRGwgNixvQ
Aqa can do one
Original post by sockface
yh... there were 13-14 hydrogens right??

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)
Yep!! Sorry that's what I meant!
Anyone willing to predict grade boundaries? I do think they'll go down and spread out a bit compared to last year's:
My guesses:

120 UMS = 90/100108 UMS (A*) = 82/100A = 74/100etc.
Original post by NobodyCares
I put because it was soluble but wasnt sure


lidocaine is basic so adding hydrogen chloride would make it a neutral pH so that it wouldnt harm the patient, thats what i put
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! 😠
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
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?
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.
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
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
Is anyone making a change.org petition?
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?
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 :smile:
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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