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    What are the 2 Main Redox equations we have to know, for the titrations. Im sure they are Cr with something and Mn with something else.
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    (Original post by Willyg11)
    Half the colour?

    If it's a hyphenated such as to yellow-green
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    (Original post by jwest)
    with the 2+ ions in excess ammonia, does it form [m(h20)2(nh3)4]2+
    and with 3+ ions [m(nh3)6]3+ or other way around?
    On the 2+ front: little NH3 forms M(H20)4(OH)2
    In excess, some forn ammonia ligands

    3+: little ammonia forms M(H2O)3(OH)3
    In excess for Cr3+ forms (Cr(NH3)6)3+

    some of the ammonia ligands with the 2+: some complexes are just oxidised to 3+

    Hope this helps
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    Thank **** this is a crammable paper.

    Hopefully all that cramming experience from my exams this year and my exams last year helps in efficient cramming...
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    with excess ammonia does fe2+ form fe(h2o)4(oh)2 and 2NH4+
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    could someone please answer my q on cell diagrams
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    (Original post by Ebony_x)
    Guys in the specimen paper I thought the decomposition of calcium carbonate is:
    CaCO3 ----> CaO + CO2..
    The markscheme says CaCO3 ---> CaO + CO ??!!!??
    Yeah, I thought that too.
    It might just be an error on the MS because one of the answers to the next question says that CO2 is produced.
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    please someone help
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    (Original post by SittingOnCornflakes)
    Yeah, I thought that too.
    It might just be an error on the MS because one of the answers to the next question says that CO2 is produced.
    Hmm yeah I just thought its always CO2 produced, even wiki says that...
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    how do you know when to write h2o and h+ in cell diagrams?
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    (Original post by Willyg11)
    On the 2+ front: little NH3 forms M(H20)4(OH)2
    In excess, some forn ammonia ligands

    3+: little ammonia forms M(H2O)3(OH)3
    In excess for Cr3+ forms (Cr(NH3)6)3+

    some of the ammonia ligands with the 2+: some complexes are just oxidised to 3+

    Hope this helps
    cool, so is cr3+ the only one that can have excess ammonia and fe3+,Al3+ can only have a little?
    sorry for the further questions
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    What are the 2 Main Redox equations we have to know, for the titrations. Im sure they are Cr with something and Mn with something else.
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    (Original post by Zabukar)
    What are the 2 Main Redox equations we have to know, for the titrations. Im sure they are Cr with something and Mn with something else.
    (cr2o7)2- + 14H+ 6e- ---> 2cr3+ + 7h20


    (MnO4)- + 8H+ + 5e- -----> Mn2+ + 4H20

    i think
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    we dont need to know atom economy or percentage yield do we?:confused:
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    Cr with excess NH3 is insoluble right?
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    Eeeh I can do the transition metal qs now
    I just hope the redox are nice.
    ^Also, they may well ask about it but it's just revision from last year, you'll be fine
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    (Original post by Rahul_V)
    we dont need to know atom economy or percentage yield do we?:confused:
    It's synoptic so it can ask anything from unit 4 - unit 1. Sometimes it asks you for % or something when working out titration calculations.
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    (Original post by Ebony_x)
    Hmm yeah I just thought its always CO2 produced, even wiki says that...

    Then it must be right!

    But yeah, AQA do a great job of messing with our minds. :mad:
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    (Original post by Zabukar)
    It's synoptic so it can ask anything from unit 4 - unit 1. Sometimes it asks you for % or something when working out titration calculations.
    very hardly synoptic
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    (Original post by SittingOnCornflakes)
    Then it must be right!

    But yeah, AQA do a great job of messing with our minds. :mad:
    Yeah they do alright! Hope we get a good paper tomorrow!
 
 
 
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