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    Can anyone give a rough overview about what happens at each electrode in a fuel cell? Pleasee
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    (Original post by alow)
    wtf are you on about
    I was making the (crude) assumption that he's talking about reacting Mg(OH)2 with an acid. As during buffer/neutralisation questions they'd state to add Mg(OH)2, not just leave it as "Mg2+".
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    lol i find last year's paper hard
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    (Original post by ShannonD_1697)
    Could someone quickly explain how ionic size and charge effects lattice enthalpy?
    There's a really good description of it from here:
    http://www.chemguide.co.uk/physical/...s/lattice.html
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    (Original post by sydneyl3igh)
    Can anyone give a rough overview about what happens at each electrode in a fuel cell? Pleasee
    You have both alkali and acidic half equations (I'm fairly sure you need to memorise both, it can be derived but takes time). I posted them a few pages ago.
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    (Original post by BioStudentx)
    I was making the (crude) assumption that he's talking about reacting Mg(OH)2 with an acid. As during buffer/neutralisation questions they'd state to add Mg(OH)2, not just leave it as "Mg2+".
    Please never call a metal ion a base. That is incorrect in every way.
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    (Original post by alow)
    Please never call a metal ion a base. That is incorrect in every way.
    So in answer to his question, adding "Mg2+ (whatever that means)" will shift the position of eqbm in which direction? Or is that not even a thing? I think he meant Mg(OH)2?
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    (Original post by BioStudentx)
    So in answer to his question, adding "Mg2+ (whatever that means)" will shift the position of eqbm in which direction? Or is that not even a thing? I think he meant Mg(OH)2?
    Shift to the left, there's less [HA] and more [A-]
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    (Original post by tomlam)
    Shift to the left, there's less [HA] and more [A-]
    So is Mg2+ an acid or a base? >.< Holy **** i'm screwed (and confused).
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    Can someone explain the Buffer solution question for june 15? The mg part?

    Posted from TSR Mobile
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    (Original post by BioStudentx)
    So is Mg2+ an acid or a base? >.< Holy **** i'm screwed (and confused).
    Transition metal ions can be considered Lewis acids, like halogen carriers such as FeBr3.
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    (Original post by alow)
    Please never call a metal ion a base. That is incorrect in every way.

    I agree. HA would react with the Mg2+ ions but a proton itself would be repelled by the positive charges. Its the OH- in Mg(OH-)2 that makes it a base. So yes it would react with the HA Itself but not the protons.

    CH3COOH <---------> CH3COO- + H+

    Mg2+ would form Mg2+(CH3COO-)2 + 2H+

    So for the buffer, the equilibrium would move ultimately left as more CH3COO- ions and H+ ions would be produced from reaction with Mg2+.
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    (Original post by alow)
    Transition metal ions can be considered Lewis acids, like halogen carriers such as FeBr3.
    Rightt? But it doesn't actually have a proton to donate?

    [HA]<---> [H+] + [A-]

    So it reacts with A- and equilibrium shifts to the left?
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    (Original post by BioStudentx)
    So is Mg2+ an acid or a base? >.< Holy **** i'm screwed (and confused).
    +1 dw, wish i never read this thread now... it cant give any H+ ions how can it be an acid LOL
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    (Original post by BioStudentx)
    Rightt? But it doesn't actually have a proton to donate?

    [HA]<---> [H+] + [A-]

    So it reacts with A- and equilibrium shifts to the left?
    I said a Lewis acid, not a Brønsted–Lowry acid.
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    (Original post by BanterBus)
    +1 dw, wish i never read this thread now... it cant give any H+ ions how can it be an acid LOL
    A Lewis acid.
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    (Original post by BioStudentx)
    So is Mg2+ an acid or a base? >.< Holy **** i'm screwed (and confused).
    It's acting as a conjugate acid
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    (Original post by alow)
    Transition metal ions can be considered Lewis acids, like halogen carriers such as FeBr3.
    alow m8 just allow it, for this spec we dont need to know Lewis acids, take it to another thread.
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    (Original post by BanterBus)
    alow m8 just allow it, for this spec we dont need to know Lewis acids, take it to another thread.
    Clearly you do, because if not you won't be able to understand these equilibria.
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    (Original post by alow)
    A Lewis acid.
    haven't kept up with the discussion in recent minutes but where's the lone pair that it's accepting to become a lewis acid?
 
 
 
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