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    (Original post by choc1234)
    how do you know when to write h2o and h+ in cell diagrams?
    If its in the original half equation you add it in the cell diagram.
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    Anyone have any ideas how to do question 3bi in the specimen paper? I thought it was V3+ as the species present, but its clearly not!??
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    (Original post by NRican)
    Cr with excess NH3 is insoluble right?
    ?

    Book says CrNH306 is a purple soln??
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    (Original post by Ebony_x)
    Anyone have any ideas how to do question 3bi in the specimen paper? I thought it was V3+ as the species present, but its clearly not!??
    See post number 113 (page 6)
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    Off to sleep, good luck everyone
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    (Original post by Ebony_x)
    Yeah they do alright! Hope we get a good paper tomorrow!
    Good Luck!
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    (Original post by SittingOnCornflakes)
    Good Luck!
    Good luck to you as well!
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    I'm getting tired.
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    (Original post by Luke0011)
    I'm getting tired.
    Me too, don't give up, it's almost over. :hugs:

    (Hello fellow med applicant :jive:)
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    (Original post by Sparkly-Star)
    Me too, don't give up, it's almost over. :hugs:

    (Hello fellow med applicant :jive:)
    I'm a REapplicant now haha!

    I may be going to sleep soon, i think i've done enough revision! if i dont know it now i wont know it tomorrow! :P
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    (Original post by jimmy303)
    See post number 113 (page 6)
    Wow you an absolute genius to work that out thanks and repped!
    I wouldnt of thought of it like that, I just see V2+ as reducing agent and that gets oxised into v3+, but this clearly just keeps getting oxidsed.. dont quite get how MnO2 can do this though?
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    (Original post by Luke0011)
    I'm a REapplicant now haha!

    I may be going to sleep soon, i think i've done enough revision! if i dont know it now i wont know it tomorrow! :P
    Aww yeah, I wish I could've taken a gap year, I'm just going for my back-up. Good luck tomorrow. Yeah haha that's why I am going over it once more before bed and once more before exam tomorrow. Too much to remember. :p:
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    What do we need to know about non/rehargeable/fuel etc cells? Can someone please summarise the main points?? The spec isn't clear enough :/ Thanks
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    quick peeps
    (Al(OH)4)^-..or...(Al(OH)6)^3-
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    (Original post by strawberry_cake)
    What do we need to know about non/rehargeable/fuel etc cells? Can someone please summarise the main points?? The spec isn't clear enough :/ Thanks
    textbook says we dont need to know them in detail so..i don't anyway spec just says "appreciate", i think tey'll just give us something to apply knowledge of electrochemical cells to,not ask "what is a daniell cell " or someething. well hopefully anyway :L
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    (Original post by Luke0011)
    I'm getting tired.
    Me too

    (Original post by Sparkly-Star)
    Aww yeah, I wish I could've taken a gap year, I'm just going for my back-up. Good luck tomorrow. Yeah haha that's why I am going over it once more before bed and once more before exam tomorrow. Too much to remember. :p:
    Aw what happened to the all nighter?? although I'm getting very tired too, I think its just the boringness of chem5 :/ I still have chaps 13-16 to review over and mod1 :cry2:

    EDIT : And that table.. I can never remember the colours
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    Gooooodnight; too much chemistry in my head. It hurts.
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    (Original post by chrissyyip)
    quick peeps
    (Al(OH)4)^-..or...(Al(OH)6)^3-
    1st
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    (Original post by Ebony_x)
    Wow you an absolute genius to work that out thanks and repped!
    I wouldnt of thought of it like that, I just see V2+ as reducing agent and that gets oxised into v3+, but this clearly just keeps getting oxidsed.. dont quite get how MnO2 can do this though?
    It's like when you add zinc and HCl to Cr2O7(2-)

    Cr2O7(2-) is reduced to Cr3+ (orange to green) and is then oxidised again by zinc and HCl to Cr2+ (blue) though this is unstable and oxidises back to Cr3+ if air is present.

    In the question it says MnO4- is in excess so although some is used up to oxidise V2+ to V3+ (making Mn2+) there is still some MnO4- left over.

    Remember to check the electrode potentials. The MnO4-/Mn2+ electrode is more positive than all the reactions involving vanadium ions so MnO4- will always oxidise any vanadium ions present
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    Why are some electron affinity endo and some exo?
 
 
 
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