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    (Original post by selenmer)
    Hi there sorry but do you know how much that chiral carbon question was??? Im so worried coz i didnt see that question so i didnt answer it
    It was a question where ypu had to mark the chiral c or something like that
    The one where you had to draw the tripeptide and label the chiral centres was 2 marks.


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    (Original post by lukemurp890)
    The one where you had to draw the tripeptide and label the chiral centres was 2 marks.


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    Thanks for ypur reply so the whole thing was 2 marks? Or just the chiral c? Im so annoyed i didnt see the part of the q asking you to mark the chiral cs
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    (Original post by selenmer)
    Thanks for ypur reply so the whole thing was 2 marks? Or just the chiral c? Im so annoyed i didnt see the part of the q asking you to mark the chiral cs
    The whole thing was 2 marks, one mark for the correct structure, and the other mark for the correct chiral centres.


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    (Original post by selenmer)
    Hi there sorry but do you know how much that chiral carbon question was??? Im so worried coz i didnt see that question so i didnt answer it
    It was a question where ypu had to mark the chiral c or something like that
    That question worth 2 marks exactly .
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    thank you! does anyone know how to work out 5D?



    https://6d92be79f827f62dea9388a0df05...%20Buffers.pdf
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    (Original post by Hunnybeebee)
    thank you! does anyone know how to work out 5D?



    https://6d92be79f827f62dea9388a0df05...%20Buffers.pdf

    HINT: OH- Concentration is 100 times of h+ concentration
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    (Original post by Hunnybeebee)
    thank you! does anyone know how to work out 5D?



    https://6d92be79f827f62dea9388a0df05...%20Buffers.pdf
    Do you have the answer, I got a pH of 8.
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    (Original post by Hunnybeebee)
    thank you! does anyone know how to work out 5D?



    https://6d92be79f827f62dea9388a0df05...%20Buffers.pdf
    Kw=[OH-][H+]
    [OH-]=100[H+]
    10^-14=100[H+]^2
    [H+]=10^-8
    PH=-Log(10^-8)
    PH=8

    Hope that helps
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    (Original post by HFancy1997)
    Kw=[OH-][H+]
    [OH-]=100[H+]
    10^-14=100[H+]^2
    [H+]=10^-8
    PH=-Log(10^-8)
    PH=8

    Hope that helps
    where does the square come from?
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    (Original post by suibster)
    where does the square come from?
    [OH-] = 100 [H+]

    so you can sub that into Kw = [H+][OH-] to get:

    Kw =100 [H+] x [H+]

    Kw = 100[H+]^2
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    (Original post by RetroSpectro)
    [OH-] = 100 [H+]

    so you can sub that into Kw = [H+][OH-] to get:

    Kw =100 [H+] x [H+]

    Kw = 100[H+]^2

    I see.. I thought the OH- ions concentration would be used from previous question
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    (Original post by suibster)
    where does the square come from?
    [oh-]=100[h+]
    [oh-]*[h+]=100[h+]*[h+]=100[h+]^2
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    (Original post by HFancy1997)
    [oh-]=100[h+]
    [oh-]*[h+]=100[h+]*[h+]=100[h+]^2
    Because at equilibrium, [H+] = [OH-],

    so: [H+] x [OH-]

    = [H+]^2
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    (Original post by Elliot_97)
    Because at equilibrium, [H+] = [OH-],

    so: [H+] x [OH-]

    = [H+]^2
    Can anyone link me to an unofficial mark scheme for f324? Not really in the mood to look through 134 pages haha.

    Ps only quoted you because you seem helpful and active.
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    (Original post by Mr Average.98)
    Thats a interesting possibility.. but i would say it will be an A =50 marks because some questions were generally sly. And compare them with other papers .. where grade boundaries were 48 =A .. this paper was comparatively harder due to the ambiguity. So yh .. cant say for sure .. but im confident that it will be an A=50
    .
    I doubt it'll even be 50 a 50 for an A is what you call the January 2013 f324 which wasn't ambiguous have a feeling this will be about 48 for an A chemistry is a subject where it's easy to lose stupid marks like math
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    F325 2015 mark scheme anyone?

    nvm found it
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    Hi could someone explain the carbonic acid-hydrogencarbonate buffer system?
    Thanks
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    (Original post by Hunnybeebee)
    thank you! does anyone know how to work out 5D?



    https://6d92be79f827f62dea9388a0df05...%20Buffers.pdf
    (Original post by suibster)
    HINT: OH- Concentration is 100 times of h+ concentration
    (Original post by RetroSpectro)
    Do you have the answer, I got a pH of 8.
    (Original post by HFancy1997)
    Kw=[OH-][H+]
    [OH-]=100[H+]
    10^-14=100[H+]^2
    [H+]=10^-8
    PH=-Log(10^-8)
    PH=8

    Hope that helps
    (Original post by RetroSpectro)
    Do you have the answer, I got a pH of 8.
    Hey do you know where i can find the mark scheme for this paper?
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    Is my two step mech wrong? If so why? Diff to ms

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    (Original post by itsConnor_)
    Is my two step mech wrong? If so why? Diff to ms

    Posted from TSR Mobile

    Is the rate equation given ?


    edit: nvm just saw it
 
 
 
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