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    (Original post by Boundless_x)
    What about if they ask for [Al(H20)6]2+ with excess OH?
    [Al(H2O)6]3+ + 6OH- ===> [Al(OH)6]3- + 6H2O
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    (Original post by SirRaza97)
    [Al(H2O)6]3++ 4OH- ===> [Al(OH)4] - + 6H2O

    it's aliminium 3+ not 2+
    Thanks
    Ahh yeah it is...I'm so tired that I've forgotten how to distinguish between different numbers
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    Can always use KNO3 in the salt bridge?
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    (Original post by GO97)
    how do you suss out which species to use as the salt bridge of a cell
    I usually go for KNO3 but just make sure that the salt bridge won't react with the reagents on either side.
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    (Original post by Hopefulmedic15)
    [Al(H2O)6]3+ + 6OH- ===> [Al(OH)6]3- + 6H2O
    I've seen this one in pastpapers
    (Original post by SirRaza97)
    [Al(H2O)6]3++ 4OH- ===> [Al(OH)4] - + 6H2O

    it's aliminium 3+ not 2+
    This one is in my notes...

    Which one are we supposed to use?
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    (Original post by Boundless_x)
    Thanks
    Ahh yeah it is...I'm so tired that I've forgotten how to distinguish between different numbers
    It won't only be 4OH- if it's in excess!

    EDIT scratch that the book says it would be 4OH-

    2nd edit, I also thought I saw it with 6 in past papers, so I don't know tbh

    3rd edit, just found this on the AQA chem 5 page for wiki books and it says it goes to [Al(OH)6]3- in excess OH- but tbh, both would form a colourless solution
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    (Original post by study2016)
    Guys - if you would recommend I do any 3 CHEM5 papers, which ones would they be? Very short for time - hectic exam timetable
    I found June 2012 pretty hard
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    Best of luck for tomorrow everyone!! lets smash this exam! ( to make up for chem 4 haha!)
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    (Original post by ChlorophyllA)
    Cobalt with excess OH-: [Co(H2O)6)2+ + 2OH- --> Co(H2O)4(OH)2 + 2H20
    isnt this also the equation with little hydroxide
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    Does anyone know the general method of calculation when you have to use the specific heat capacity of water and the mass of something?
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    (Original post by Boundless_x)
    I've seen this one in pastpapers


    This one is in my notes...

    Which one are we supposed to use?
    I've got a different one...
    I have:

    Al(H2O)3(OH)3 + OH- --> [Al(H2O)2(OH)4]- + H2O

    ..... :/


    Posted from TSR Mobile
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    (Original post by Hopefulmedic15)
    I usually go for KNO3 but just make sure that the salt bridge won't react with the reagents on either side.
    what else apart from potassium nitrate can you use?
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    (Original post by Lilly1234567890)
    isnt this also the equation with little hydroxide
    The 2+ ions don't actually react with excess NaOH, only excess NH3. They react with limited NaOH to give [M(H2O)4(OH)2]
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    (Original post by werdo1997)
    The 2+ ions don't actually react with excess NaOH, only excess NH3. They react with limited NaOH to give [M(H2O)4(OH)2]
    yeah that what i meant- as when the +2 metal reacts with little hydroxide isnt that^ the equation we use?
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    (Original post by 26december)
    I've got a different one...
    I have:

    Al(H2O)3(OH)3 + OH- --> [Al(H2O)2(OH)4]- + H2O

    ..... :/


    Posted from TSR Mobile
    That's the right one!
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    (Original post by Boundless_x)
    I've seen this one in pastpapers


    This one is in my notes...

    Which one are we supposed to use?
    Can I see the past paper where this was???
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    Any predictions for topics tomorrow?
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    (Original post by Lilly1234567890)
    yeah that what i meant- as when the +2 metal reacts with little hydroxide isnt that^ the equation we use?
    Oh sorry, yep that equation
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    (Original post by Lilly1234567890)
    what else apart from potassium nitrate can you use?
    ive seen kcl
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    (Original post by study2016)
    Guys - if you would recommend I do any 3 CHEM5 papers, which ones would they be? Very short for time - hectic exam timetable
    June 12
    Jan 13
    June 10

    (Original post by Lilly1234567890)
    why topics from AS are you guys looking back at?
    None
 
 
 
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