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    So I lost most of the marks on the ratio question, I couldn't get the equations on the ethanol question, I somehow managed to get the Born-Haber cycle question wrong , I lost the mark on why CO2 is released when recharging the cell as well as lots of others. But as there were also quite a few easy marks (17 marks on transition metal colours etc.), I think the grade boundaries will be quite high. :cry2:
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    (Original post by marleyxd)
    For the transition metal complexes questions, did people write ionic or overall equations?

    I wrote both for each reaction because it said write overall equations....
    it said overall so i used the overall one.
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    (Original post by SpiggyTopes)
    What was the aldehyde question?
    Ethanal got oxidised to ethanoic acid (I think). They gave us an equation then asked something about why cobalt catalyses the reaction (I think) and to write 2 equations.
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    (Original post by Grauniad)
    For the reaction demonstrating why MgO was a basic oxide, why was it worth two marks? I hazarded MgO + 2HCl --> MgCl2 + H20, but I'm not sure how it amounts to two marks when the (arguably harder) one with NaOH and P4O10 was only worth 1.


    Also, question 7 was probably the most tedious thing I've ever had to do in my life.
    wasn't it the reaction with water? MgO + H20 ---> Mg(OH)2
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    I used CO3 2- etc... that will be fine it will never be penalised
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    what was the equation and colours for the aluminium in excess ammonia?
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    (Original post by Pinkhead)
    it said overall so i used the overall one.
    I think it meant overall in that you were meant to add all the Ammonia in one go, for instance, rather than just taking a proton off each time. At least, I hope that's what it meant
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    (Original post by gizmokaka)
    wasn't it the reaction with water? MgO + H20 ---> Mg(OH)2
    yes I suppose you could have done that ... but it doesnt really react with water...
    I reacted it with HCl to give MgCl2 and water
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    (Original post by Grauniad)
    For the reaction demonstrating why MgO was a basic oxide, why was it worth two marks? I hazarded MgO + 2HCl --> MgCl2 + H20, but I'm not sure how it amounts to two marks when the (arguably harder) one with NaOH and P4O10 was only worth 1.


    Also, question 7 was probably the most tedious thing I've ever had to do in my life.
    i thought it asked you to suggest an experiment to prove that the bonding is ionic?
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    (Original post by Pinkhead)
    it said overall so i used the overall one.
    So for the HCl one, the one with Cu(H2O)6 would be
    Cu(H20)6 + 4HCL --> Cu(Cl)4 + 6H2O + 4H+
    ??
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    (Original post by SpiggyTopes)
    A*
    I highly doubt that. XD I've probably dropped a lot more anyway but just can't remember. I do need an A* though because I got a C in chemistry unit 4 because I got food poisoning.
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    (Original post by gizmokaka)
    wasn't it the reaction with water? MgO + H20 ---> Mg(OH)2
    No an acid and a base gives a salt and water
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    CH3CHO + Co3+ + H2O > Co2+ + CH3COOH + 2H+ + e-
    2H+ + CH3CHO + O2 + Co2+ + e- > Co3+ + CH3COOH + H2O

    Two catalytic equations.
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    (Original post by gizmokaka)
    wasn't it the reaction with water? MgO + H20 ---> Mg(OH)2
    Ooh, damn, it may well have been. Still don't understand why it was worth two marks though
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    do you think finding the total moles of Cl- using the moles of AgCl and finding the number of moles of Co2+ will get 2/5 on the last question?
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    (Original post by Grauniad)
    I think it meant overall in that you were meant to add all the Ammonia in one go, for instance, rather than just taking a proton off each time. At least, I hope that's what it meant
    yup, just add the 6NH3 in one go
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    (Original post by Pinkhead)
    i thought it asked you to suggest an experiment to prove that the bonding is ionic?
    You did, you melt it and if it conducts then it's ionic. :-)
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    (Original post by extons)
    CH3CHO + Co3+ + H2O > Co2+ + CH3COOH + 2H+ + e-
    2H+ + CH3CHO + O2 + Co2+ + e- > Co3+ + CH3COOH + H2O

    Two catalytic equations.
    oh no...that's definitely not what I got - I had one half equation where oxygen was reduced to water and then another where ethanal was oxidised to ethanoic acid. The waters then cancelled...
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    (Original post by Pinkhead)
    i thought it asked you to suggest an experiment to prove that the bonding is ionic?
    Both questions were asked
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    (Original post by extons)
    CH3CHO + Co3+ + H2O > Co2+ + CH3COOH + 2H+ + e-
    2H+ + CH3CHO + O2 + Co2+ + e- > Co3+ + CH3COOH + H2O

    Two catalytic equations.
    Meh, got the first one right but the second one wrong.
 
 
 
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