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Aqa chem4 15th june 2011 (resit) thread

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Reply 880
Avatar for angel1992
angel1992
also what did people get for all the different ph's and how you work them out?
Reply 881
Avatar for JK471993
JK471993
2
Original post by flowersandtrees
Well considering they're 6 hours ahead of us, that is highly unlikely.


Haha of course! That explains the New Years fireworks. Thank you!
Reply 882
Avatar for rt_92
rt_92
Original post by Pendulii
Was the IUPAC name of phthalic acid benzene-1,2-dicarboxylic acid or benzene-1,2-dioic acid?



I put benzene-1,2-dicarboxylic acid.. Which i thought was right.. :s-smilie:
http://msds.chem.ox.ac.uk/PH/phthalic_acid.html
This paper was hard.....
Original post by Holocaene
Nucleophilic addition-elimination with exess NH3 in aqueous solution. The aqueous probably wasn't important.


You didn't have to use excess NH3 the Q was 5 marks 1 for the mechanism name and 4 for arrows. Excess NH3 was not part of it although not wrong.
Reply 885
Avatar for JK471993
JK471993
2
Did everyone put every single bond for the displayed formula one?
Reply 886
Avatar for gr8_dude
gr8_dude
1
Original post by FristyKino
So how many of you missed out that last 3 marker? :tongue:


i nearly did, but i think i got the answer wrong anyway so it wouldnt of made much difference if i didnt do it anyway :P
Reply 887
Avatar for angel1992
angel1992
did any one get 11.89 for any of their ph's?
Reply 888
Avatar for Holocaene
Holocaene
Original post by Casshern1456
You didn't have to use excess NH3 the Q was 5 marks 1 for the mechanism name and 4 for arrows. Excess NH3 was not part of it although not wrong.


Pretty sure it specified you shouldn't put down mechanisms for that one, it just wanted reagents, conditions etc.


Original post by JK471993
Did everyone put every single bond for the displayed formula one?

Oh dear =P what question was that, I really must learn to read.
Original post by angel1992
did any one get 11.89 for any of their ph's?


Quite a few people did, but I think we got it wrong. :/
Reply 890
Avatar for angel1992
angel1992
can some one go through the last two ph's?
Reply 891
Avatar for Saima_x
Saima_x
Original post by cleo101
wat was the name of the n-substituted amine formed?


N-methyl-propanamide?

Did anyone else get this?
Reply 892
Avatar for Holocaene
Holocaene
Original post by angel1992
can some one go through the last two ph's?


if you mean the two four markers with KOH and ethanoic acid I posted the worked solutions up a few pages back, just look at posts I've made

Original post by Saima_x
N-methyl-propanamide?

Did anyone else get this?


Yeah everyone at my school put this, fairly sure its right.
(edited 12 years ago)
Reply 893
Avatar for angel1992
angel1992
Original post by al_habib
racemate- is it 50:50 mixture of equal enantiomers


what was this question for?
Reply 894
Avatar for Saima_x
Saima_x
What did everyone put for the question about pthlates or whatever it was lol. The one about adverse effects on humans, what would need to be done for the public to feel more confident about the use of them? (It was something like that..)
Original post by Holocaene
Pretty sure it specified you shouldn't put down mechanisms for that one, it just wanted reagents, conditions etc.



Oh dear =P what question was that, I really must learn to read.


This was in the middle pages reaction between Propyl Chloride CH3CH2COCL and Methyl amide CH3NH2, not the other one.
Original post by Saima_x
Yep I did! But everyone seems to be saying that's wrong?!!! :frown:


Well others say that they divided through the volume, which I dont see why. I just scaled up the excess moles to 1000 cm3 which gave you the concentration of ethanoic acid and at the top of the question they repeated the Ka value of ethanoic acid so it used it to work out [H] and used that to find the pH.

The second question is the same except you get the excess moles for OH and you scale that up to 1000cm3 to get [OH] and then you use kw=[OH][H] to find [H] and hence the pH.
Original post by cleo101
wat did everyone name the compound which had amine group alcohol and cooh :confused:


3-hydroxy, 2-aminopropanoic acid
Reply 898
Avatar for al_habib
al_habib
1
dynamic equilibrium is it rate of forward reaction=rate of backward reaction, all the states are similar. will this gain me 2mks
Reply 899
Avatar for gr8_dude
gr8_dude
1
Original post by Casshern1456
3-hydroxy, 2-aminopropanoic acid

i think you need to put 2-amino 3-hydroxypropanoic acid, as arent you meant to put them in alphabetical order?

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