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    (Original post by Hopefulmedic15)
    It's still being oxidised from Co2+ ---> Co3+

    If it's just in air it's:

    [Co(NH3)6]2+ ===> [Co(NH3)6]3+ + e-
    If it's in air its 4[Co(NH3)6]2+ + O2 + 2H2O ===> 4[Co(NH3)6]3+ + 4OH-
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    well went bad to worst now. Came early out of exams didn't know what to do in many parts
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    I found it mostly easy but I don't want to get my hopes up. The questions i didn't get were:
    What is the effect on emf of increasing pressure of oxygen?
    Ditto for effect of increasing Pt surface area
    Conditions under which E for something was something (I put in circuit with standard hydrogen electrode with 298K etc)

    For the titration calculation I out something like 96%? Sneaky of them to make the compound have three C2O4 ions in

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    I think I got like 80.9 for the purity
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    Was the mole ratio 2:5 for the calculation equation 2 manganite to 5 ethane dioate
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    what was the answer to the K2O bornhaber cycle?
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    94.4% purity anyone?
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    (Original post by 1010marina)
    94.4% purity anyone?
    yaaahh
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    94.4% purity anyone??? :/
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    (Original post by 1010marina)
    94.4% purity anyone?
    Yeah
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    (Original post by 1010marina)
    94.4% purity anyone?
    How did you do it?
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    (Original post by 1010marina)
    94.4% purity anyone?
    Unfortunately I agree with you, put something else though haha
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    (Original post by ASLEVELSHELPME)
    what was the answer to the K2O bornhaber cycle?

    Can't remember exactly but I got something like +2240
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    (Original post by 1010marina)
    94.4% purity anyone?
    Yeah, phew

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    Predicted grades boundaries? Easy paper, so what's the highest it's ever been for an A and A*? I need an A* to bump up my grade so this is a bit annoying

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    Accidentally did MnO4- to Mn3+.... got confused with dichromate, will I lose all the 7 marks?
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    (Original post by Charco63)
    Can't remember exactly but I got something like +2240
    Thank god
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    (Original post by Charco63)
    Can't remember exactly but I got something like +2240
    It was 2238
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    Isnt the MnO4:FeC2O4 ratio 3:5?
    I used that and ended up getting 53% purity
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    (Original post by study2016)
    Isnt the MnO4:FeC2O4 ratio 3:5?
    I used that and ended up getting 53% purity
    Nah 2:5

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