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OCR A2 CHEMISTRY F324 and F325- 14th and 22nd June 2016- OFFICIAL THREAD watch

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    (Original post by postexamtalk)
    H2O2 + I- forms HIO + OH-
    H+ + OH- forms H2O
    HIO + H+ forms I2 + OH- (given)
    H+ + OH- forms H2O

    Both valid?
    Need 2I- on the left-hand side
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    (Original post by k.russell)
    For the question about acidic or alkaline at 60'C with a pH of 7, did no one use 10^-7 = [H+]? Because that statement has to true by definition doesn't it? So I then divided the Kw at 60'C, (which was 9.4 blah blah x 10^-14) by 10^-7, giving 9.4 blah blah x 10^-7 for [OH-] then I said that [H+] > [OH-] so the solution is acidic. Sorry to go against the flow, but my method makes complete sense to me and I think it's right, if anyone can show me why that's wrong, please go ahead (or if you think I'm talking sense please back me up lol)
    Your method is right however your conclusion is wrong 9.4x10^-7 >1x10^-7 hence solution is alkali
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    I got that one too


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    It said leave the answer in standard form
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    (Original post by bridget07)
    How many marks was the AgNO3 equilibrium shift?
    4 marks
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    (Original post by Randall13)
    What did people get for the empirical formula one?

    I got the fact it was the same as the molecular formula but not 100% on it.
    There was one Cu so it was the molecular.
    anyway I got CuO8H4C4 with 2- charge?

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    Yh i got that too

    (Original post by Randall13)
    What did people get for the empirical formula one?

    I got the fact it was the same as the molecular formula but not 100% on it.
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    Pretty sure the reagent was starch and the observation was blue/black to colourless. You can type it into YouTube and see the end point; and that's what happened
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    (Original post by HFancy1997)
    There was one Cu so it was the molecular.
    anyway I got CuO8H4C4 with 2- charge?

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    O10 as there was oxygen in the water
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    Is there an Unofficial mark scheme yet?
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    It was CuO10H4C4
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    For the question that said "use appropriate significant figures"
    Did anyone use 4 sig fig?
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    (Original post by Brandoncarlin)
    Need 2I- on the left-hand side
    didn't need 2I-, only one, in the rate equation there was [I-]^1 and [H+]^2
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    (Original post by mh0133)
    It was CuO10H4C4
    Yeah and did you get the charge to be 2-?
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    What balanced equation did you get for gold reacting with water or whatever it was
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    Help?! I need to get at least a B. But F325 was hard for me. I got a B last year, and i have almost full marks for ISA and im sure i got a high B in F324, so what is the minimum grade i can afford to get to scrape a B??????
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    Am I the only one that got x =9


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    (Original post by Clankdroid)
    didn't need 2I-, only one, in the rate equation there was [I-]^1 and [H+]^2
    I don't remember H+ being in the rate equation, only H2O2 and I-
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    (Original post by Clankdroid)
    didn't need 2I-, only one, in the rate equation there was [I-]^1 and [H+]^2
    It gave you rate equation and H+ was order 0? I2 and h202 were first order each

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    (Original post by avocadomash)
    For the question that said "use appropriate significant figures"
    Did anyone use 4 sig fig?
    I did🙋🏻
 
 
 
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