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Aqa chem4 15th june 2011 (resit) thread

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    How about h20 reacting with acid chloride to produce misty fumes? is that not a valid reaction? also the one with the 10 dm3 for the rate reaction did u times your answer by 10 at the end?
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    (Original post by JK471993)
    Did everyone put every single bond for the displayed formula one?
    which one?
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    (Original post by FristyKino)
    I put benzene-1,2-dioic acid
    I put 1,2- dibenzoic acid
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    (Original post by Holocaene)
    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



    Yeah everyone at my school put this, fairly sure its right.
    there wasn't a need for the hyphen between methyl and propanamide
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    (Original post by korz)
    How about h20 reacting with acid chloride to produce misty fumes? is that not a valid reaction? also the one with the 10 dm3 for the rate reaction did u times your answer by 10 at the end?
    i times it by 8 because one they both doubled and one term was ^2 and the other ^1. not sure though?
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    (Original post by angel1992)
    what was this question for?
    Q10
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    (Original post by Black Butler)
    I put 1,2- dibenzoic acid
    isnt the iupac name benzene-1,2-dicarboxylic acid?? :confused:
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    lol i though benzene-1,2-dicarboxylic acid and benzene-1,2-dioic acid are the same thing? i wrote the second one...
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    hey guys..

    for the Kw one..

    my answer was to the 2.98 x 10 (to the power) -15...

    i thought it had to be to the power -14 so wrote (after the above number) 0.298 x 10 (to the power) -14..

    what did everyone else get?
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    (Original post by Scarface-Don)
    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.
    That's exactly what I did! Some people in my school did H = Ka x (acid/salt) but it wasn't a buffer question!! I got 3.02 by doing the exact method you described :confused:
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    (Original post by gr8_dude)
    i think you need to put 2-amino 3-hydroxypropanoic acid, as arent you meant to put them in alphabetical order?
    They'll let you have both. I looked at 3-hydroxy, 2-aminopropanoic acid on google and it comes up so it right?
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    (Original post by superpurple)
    lol i though benzene-1,2-dicarboxylic acid and benzene-1,2-dioic acid are the same thing? i wrote the second one...
    They are the same thing aren't they? I think you'd get awarded the mark for either one of them..
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    (Original post by Saima_x)
    That's exactly what I did! Some people in my school did H = Ka x (acid/salt) but it wasn't a buffer question!! I got 3.02 by doing the exact method you described :confused:
    i got 11.89 for the second one...and 2.81 (approx) for the first one..

    half neutralisation ddnt even occur to me!!
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    (Original post by Arcanine)
    Ta-da!
    I found them! are these all the topics? thank you
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    (Original post by Zakir)
    hey guys..

    for the Kw one..

    my answer was to the 2.98 x 10 (to the power) -15...

    i thought it had to be to the power -14 so wrote (after the above number) 0.298 x 10 (to the power) -14..

    what did everyone else get?
    I definitely got something to the -15. Didn't put units :/
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    (Original post by lou12)
    i times it by 8 because one they both doubled and one term was ^2 and the other ^1. not sure though?
    hmm i just rearranged it, defo didn't times by 10 though did u use those concs for the question at the end of that page?
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    (Original post by Saima_x)
    They are the same thing aren't they? I think you'd get awarded the mark for either one of them..
    I WROTE the second one too!! hey saima
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    (Original post by Zakir)
    i got 11.89 for the second one...and 2.81 (approx) for the first one..

    half neutralisation ddnt even occur to me!!
    It didn't occur to me either
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    (Original post by Zakir)
    i got 11.89 for the second one...and 2.81 (approx) for the first one..

    half neutralisation ddnt even occur to me!!
    I got 11.89 too!
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    (Original post by JK471993)
    I pu the latter. Don't know if I'm right.
    dicarboxylic acid sounds stupid. it's wrong. Diolic acid.

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