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    (Original post by peebs123)
    Can anyone explain how you calculate the temperature at which the reaction is NOT feasible?
    It's the same as the temperature at which the reaction IS feasible, because going above/ below this temperature will make the reaction feasible/ not feasible


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    (Original post by PeanutButter2000)
    I know it's been posted before but i can't find the link to the January paper, could someone put up the link or quote the post it was in please! thanks

    edit: found it!
    any chance you could post it ?
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    (Original post by marleyxd)
    If the emf of Zn is more negative than Cu it will be oxidised
    Will it tell you their emfs?
    If not how do you work them out?
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    do we need to know the colours of vandium ions?
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    (Original post by Puffy14)
    Also 1/2 bond enthalpy is atomisation?
    yes
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    (Original post by hawraaj313)
    do we need to know the colours of vandium ions?
    I don't think so


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    (Original post by Chris-69)
    Yeah, that's the question I was talking about! That's what confused me.
    hope they don't ask this

    So, ionic bonding with additional covalent character = higher Lattice dissociation but lower mpt?
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    (Original post by 16dan2life)
    hope they don't ask this

    So, ionic bonding with additional covalent character = higher Lattice dissociation but lower mpt?
    How would that work? Surely if the lattice enthalpy is strong then the melting point would be greater ?
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    Spectrophotometry method:
    1) Add appropriate ligand to intensify colour
    2) Make up solutions of known concentration
    3)Measure absorption or transmission
    4) plot graph of results or calibration curve
    5) measure absorption of unknown and compare.

    It might come up
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    (Original post by hawraaj313)
    do we need to know the colours of vandium ions?
    No in the text book it say we don't
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    someone must have the jan13 paper :'(?
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    Can some please explain 7b(ii) on jan 11.
    I don't understand how they get that equation :/


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    (Original post by lewiszorz)
    Will it tell you their emfs?
    If not how do you work them out?
    It will tell you atleast two so you can work out the third one
    For example it might tell you the emf of one cell and then the cells overall emf so you can work out the other one
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    (Original post by Chris-69)
    How would that work? Surely if the lattice enthalpy is strong then the melting point would be greater ?
    Jan 10
    Q 4e

    Lattice of AgCl compared with AgBr

    AgCl has greater l-diss because chloride ions are smaller than bromide ions, so stronger forces of attraction between Ag+ and Cl- ions. Simple enough

    second part, asks why. Answer is, AgCl has ionic bonding with additional covalent character, so forces in the lattice are stronger than pure ionic attractions.
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    (Original post by JSN)
    been getting high A's in papers, scraped a B in jan 13 :/
    I found the Jan 2013 paper really difficult as well!
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    (Original post by hawraaj313)
    do we need to know the colours of vandium ions?
    It's not mentioned on the specification
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    (Original post by strawberyy)
    Can some please explain 7b(ii) on jan 11.
    I don't understand how they get that equation :/


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    H202 + 2e- -> 2OH-
    Cr(h2o)6 2+ + 2OH- --> CrO4 2- + 3e- + 4H2O

    Join this up, it'll make the overall equation
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    Can someone put up the mark scheme for aqa chem 5 jan 13 paper


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    can someone please explain 8b in the June 2012 paper..
    Thanks
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    (Original post by FM1994)
    Can someone put up the mark scheme for aqa chem 5 jan 13 paper


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    Jan13 CHEM5.pdf
 
 
 
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