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    (Original post by TauMuon)
    I thought this paper was definitely challenging; a lot of places to slip up. Definitely much harder than June 12 which was a breeze by comparison. I personally thought Jan13 was more straightforward than this, so my prediction is mid-low 70s for an A, maybe 73? Anyway...

    I got NiSO4.7H2O for the formula of the hydrated salt.

    I got FeO4^2- for the ferrate ion (think I missed out the '2-' though )

    I got 3.12 x 10^14 g for the mass of CO2

    3.99 for the buffer

    13.6 for the alkali pH

    4.14 for the weak acid pH

    16.8 (think it was no units? Can't remember) for Kc

    -3454 kJmol^-1 for lattice enthalpy

    I completely missed the 4 marker to do with chlorine :/
    I got all these!!! Except the CO2 one :-/
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    won't all our rate answers be slightly different because it had to be " after 40 seconds"
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    (Original post by TauMuon)
    I thought this paper was definitely challenging; a lot of places to slip up. Definitely much harder than June 12 which was a breeze by comparison. I personally thought Jan13 was more straightforward than this, so my prediction is mid-low 70s for an A, maybe 73? Anyway...

    I got NiSO4.7H2O for the formula of the hydrated salt.

    I got FeO4^2- for the ferrate ion (think I missed out the '2-' though )

    I got 3.12 x 10^14 g for the mass of CO2

    3.99 for the buffer

    13.6 for the alkali pH

    4.14 for the weak acid pH

    16.8 (think it was no units? Can't remember) for Kc

    -3454 kJmol^-1 for lattice enthalpy

    I completely missed the 4 marker to do with chlorine :/

    I got all that apart from the ferrate ion (i couldn't do) and the i had the ph of bufffer to be 3.57
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    I can't believe i missed out the salt in the last question, had i included the salt, i would have got 7 but i never so i got twelve. FFS.
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    (Original post by massi1296)
    how much was the rate calculation form the graph worth, i didnt draw a tangent just did conc/time (3.4/40) and got 0.085moldm-3s-1
    dy/dy=m
    the gradian is the rate, i don't remember the numbers
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    the chlorine one was about electrode potentials, in alkali condition the OH- reacts with H+ pushing the position of equilibrium to the left, so more e- are produced in system 7, this reduces the standard potential of the cell making it lower than that of system6.
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    how many marks was the rate calculation form the graph worth? didnt draw a tangent just did 3.4/40 conc/time
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    (Original post by keepontrying)
    I got this too!
    Yay
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    (Original post by jess_m94)
    I got that for Kc. Can't remember what pH I got but my friend got 3.99. I think I did that one wrong because I'm pretty sure I didn't get it
    I got both 3.99 and put 16.75 for the kc but I don't think they'll be too picky when it comes to rounding numbers
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    (Original post by Little Wing)
    the chlorine one was about electrode potentials, in alkali condition the OH- reacts with H+ pushing the position of equilibrium to the left, so more e- are produced in system 7, this reduces the standard potential of the cell making it lower than that of system6.
    yaay i put something along those lines...
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    (Original post by massi1296)
    how many marks was the rate calculation form the graph worth? didnt draw a tangent just did 3.4/40 conc/time
    3 I believe.
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    I think you needed to 'know your stuff', have an IQ of 200, gained a PhD in advanced Maths and Chemistry, won a Nobel Prize in Chemistry and invented the freakin' fuel cell. And even then, maybe it wasn't enough for some of the questions.
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    i put the h2o breaks down into h+ and oh- in alkali conditions moving the equilibrium to left causing the cell potential to decrease so its lower than the system 6 allowing it to react
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    I was stuck on the last question for so long, figured it out after time ran out, so angry at myself I hope I can get a B at least
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    I am enraged by OCRs ridiculous wording of the question about finding the rate after 40 seconds. Use the rate equation AND the graph?! YOU ONLY HAVE TO USE THE BLOODY GRAPH
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    (Original post by talliehughes)
    I got both 3.99 and put 16.75 for the kc but I don't think they'll be too picky when it comes to rounding numbers
    It's always 3 sf or to the least accurate figure they've provided you with, so you could lose a mark for leaving it as 16.75 :-/
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    I think this was the hardest yet.. 60 for an A?....
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    (Original post by Little Wing)
    the chlorine one was about electrode potentials, in alkali condition the OH- reacts with H+ pushing the position of equilibrium to the left, so more e- are produced in system 7, this reduces the standard potential of the cell making it lower than that of system6.
    My answer was something like that, I may score a few marks for it, yay!
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    (Original post by talliehughes)
    I got both 3.99 and put 16.75 for the kc but I don't think they'll be too picky when it comes to rounding numbers
    They specifically asked for 3 sf in that question but you'll only lose 1 mark so it's okay
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    anyone got the paper?
 
 
 
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