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edexcel nuffield chemistry unit 6 synoptic watch

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    (Original post by crana)
    It wasn't an aldehyde though. An aldehyde would have reacted with Benedict's.

    By the way (not to you just in general), Brady's reagent comes up negative for carboxylic acids. The -OH modifies the properties of the =O; it isn't the same as the =O in an aldehyde or ketone.

    C=O on its OWN is a carbonyl group - in acids it's a carboxyl group together with the -OH.

    Brady's reagent is only positive for C=O in aldehydes/ketones (I am not sure about esters, but I don't think it would be positive as an ester is really a substituted carboxylic acid group and not a plain carbonyl group).
    ,

    I concede esters won't give a positive result with Brady's reagent (did a search). But it is quite odd what they did by mentioning a smell....possibly to throw us off? Sometimes I wonder if exams are meant to test your knowledge or test your sharpness to tricks lol. Your suggestion of a phenol with a ketone group side chain in such a way with a chiral carbon seems most likely:

    C6H4OH
    |
    Ch(Ch3)COCH3

    Ah well

    (Original post by cipapfatso)
    ,

    I concede esters won't give a positive result with Brady's reagent (did a search). But it is quite odd what they did by mentioning a smell....possibly to throw us off? Sometimes I wonder if exams are meant to test your knowledge or test your sharpness to tricks lol. Your suggestion of a phenol with a ketone group side chain in such a way with a chiral carbon seems most likely:

    C6H4OH
    |
    Ch(Ch3)COCH3

    Ah well
    I didn't even notice the bit about the smell! I agree it is a bit odd tho. It was only 1 mark for the formula (which i thought was a bit harsh! but at least its notmany marks lost if its wrong..)
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    damn i guess i must have read the ques wrong. i need yu guys to help me cos im cr*pping myself i surely died during the chem6 ppr but i need to know if i did enuff r8 to go to uni (need D for that ppr)

    so if ne 1 can help w the following i will be so gr8fl i will run to their house and give them a massive hug and kiss bcuz im so so desp 2 know:

    1) nickel question - what was the value of x ( i think the formula was
    Ni(H2O)x(NH3)6-x(CL2) and hav to find x value?

    2) does ne1 hav a copy of that paper?

    (Original post by magiccarpet)
    damn i guess i must have read the ques wrong. i need yu guys to help me cos im cr*pping myself i surely died during the chem6 ppr but i need to know if i did enuff r8 to go to uni (need D for that ppr)

    so if ne 1 can help w the following i will be so gr8fl i will run to their house and give them a massive hug and kiss bcuz im so so desp 2 know:

    1) nickel question - what was the value of x ( i think the formula was
    Ni(H2O)x(NH3)6-x(CL2) and hav to find x value?

    2) does ne1 hav a copy of that paper?
    I got 2 for x, as did my friend
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    crap i got 1. every1 else in my sch got 2 aswell. i so hav died inside. wel dun to u tho. i gues im not goin uni to do law, ill jus hav2b a roadsweeper for the rest of my lif. if u see me plz give me some coins in my hat at the side of the road.
    im so srewed on that paper. all my other units i got 81/90+ an i missed out the synoptic last page, and i culdnt do ne of the qs. now im so gonna faaaaaaaiiiiiiiillllllll waaaaaaaaaahhhhhhhhhh :.............( :confused: :confused: :confused: :mad: :mad:
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    (Original post by crana)
    I got 2 for x, as did my friend
    oh yeah sorry i m too upset abt my failing to hug and kis u but am v gr8fl ne way

    (Original post by magiccarpet)
    crap i got 1. every1 else in my sch got 2 aswell. i so hav died inside. wel dun to u tho. i gues im not goin uni to do law, ill jus hav2b a roadsweeper for the rest of my lif. if u see me plz give me some coins in my hat at the side of the road.
    im so srewed on that paper. all my other units i got 81/90+ an i missed out the synoptic last page, and i culdnt do ne of the qs. now im so gonna faaaaaaaiiiiiiiillllllll waaaaaaaaaahhhhhhhhhh :.............( :confused: :confused: :confused: :mad: :mad:
    Shh, calm down. I am sure there would be method marks (at least you didn't get 0.064 for x like i did the first timeround..) and synoptic has lower grade boundaries,plus you have spare marks from your other modules!

    You really can't know how you have done until you get your result because often they mark them so strangely!

    rosie

    ps. I reallythought I had failed unit 2 last year, andmy friend thought shewas doomed cos she turned over 2 pages att once andmissed an entire 2 page question.. and i got an A and shegota very high B on that module!
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    (Original post by crana)
    Shh, calm down. I am sure there would be method marks (at least you didn't get 0.064 for x like i did the first timeround..) and synoptic has lower grade boundaries,plus you have spare marks from your other modules!

    You really can't know how you have done until you get your result because often they mark them so strangely!

    rosie

    ps. I reallythought I had failed unit 2 last year, andmy friend thought shewas doomed cos she turned over 2 pages att once andmissed an entire 2 page question.. and i got an A and shegota very high B on that module!
    OMG!!! thaaaannnnkkkkksssss sssoooo much!!!! i really am dyin here!!! i read som other post that ur doing aea chem - gd luck! needless to say im not! im guessn therfor u know what ur talkn abt!
    thanks i am so worrd abt that ppr cos i did so gd all yr then i go an mess it up! thanks i feel a bit bettr now! i rly wud giv u a hug!
    but i still dont know how low the gbs will go.will w8 and see!
    thx xxxxxxxxxxxx magics xxxxxxxxxx :eek:
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    i doubt the grade boundaries will be that low. Last years boundaries seem to have been fixed, it was 46/60 for an A in unit 1 and 4; 40/60 for an A in unit 2 and 6, that despite roughly 1/2 the candidates that sat last years unit 6 getting less than 20/60 (or so an examiners report claims).

    what worries me is that last years boundary A was 40/60, and boundary B was 35/60, boundary C was 31/60. And the difference between 40 and 35 translates into a 12 mark difference once the scores are standardised.

    (Original post by wodoodporny)
    i doubt the grade boundaries will be that low. Last years boundaries seem to have been fixed, it was 46/60 for an A in unit 1 and 4; 40/60 for an A in unit 2 and 6, that despite roughly 1/2 the candidates that sat last years unit 6 getting less than 20/60 (or so an examiners report claims).

    what worries me is that last years boundary A was 40/60, and boundary B was 35/60, boundary C was 31/60. And the difference between 40 and 35 translates into a 12 mark difference once the scores are standardised.
    40/60 is 2/3 or 66% which is actually quite low to get an A (80% UMS) IMHO.
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    oh shite im soo worried now
    magic carpet..what are you worrying about?? U only need a D on this paper!!!
    dont worry so much!!
    spare a thought for ppl like me who need an A
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    yea i might only need a D but i missed a whole page out and im guessing ive only just scraped the D i need. what i meant about the grade boundaries was that the difference between the actual ums percentage for that grade and the actual raw mark as a percentage will be big. it usually will be for u6 anyway, but probably slightly more so this year if u all found it hard! theres still hope!
    i really hate chemistry now :mad:
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    (Original post by magiccarpet)
    yea i might only need a D but i missed a whole page out
    what page did you miss out? the last double page was the electrode potential graph and the E cell calculations wasn't it?
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    the very last page, i thoght at the end was a double blank page so i didnt do the one about the leucine/glycine test. i couldnt do the electrode graph either but i guessed. it really annoyed me tho, the last question was worth about 6 marks wasnt it? DAMN! :rolleyes:
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    What last question?

    can someone explain further?

    (Original post by magiccarpet)
    the very last page, i thoght at the end was a double blank page so i didnt do the one about the leucine/glycine test. i couldnt do the electrode graph either but i guessed. it really annoyed me tho, the last question was worth about 6 marks wasnt it? DAMN! :rolleyes:
    Leucine-glycine test??????????????

    I am sure I didn't do this. Don't tell me I missed it too...
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    i think the leu/gly page were the questions on the amino acid sequence of A to H

    (Original post by wodoodporny)
    i think the leu/gly page were the questions on the amino acid sequence of A to H
    :| :| I don't remember this at all. Which question was it? After the electrode potential one?
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    does ANYONE remember a last part of the last ques saying something like

    'say how to identify leucine and glycine. include a diagram of any apperatus you need and any calculations you'd do.' 6 marks

    :confused: at first i was glad i wasnt the only person to missed it out, but this is just silly. someone must have done it?
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    [QUOTE=magiccarpet]does ANYONE remember a last part of the last ques saying something like

    'say how to identify leucine and glycine. include a diagram of any apperatus you need and any calculations you'd do.' 6 marks

    QUOTE]

    I dont remember this question at all

    the last part of the very last question was calculating E cell for a reaction. At least i hope it was :rolleyes:
 
 
 
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