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    (Original post by Wish I Could Change This)
    How on earth is everyone remembering the colour changes for complex ions?
    Personally i just wrote all the colours and equations out over and over again. Takes the piss but they've managed to stick so far
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    I am also struggling with long calculations

    Question 8c

    http://store.aqa.org.uk/qual/gce/pdf...W-QP-JAN10.PDF

    Thanks
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    This was in the in tha jan 2011 paper it says,
    This is the reation at the positive electrode:
    Li+ + CoO2 + e- > Li+... etc

    But I was told that the positive ion, is attracted to the negative elctrode?

    damm im confused

    anyone???
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    (Original post by Somali-Pir8)
    does anyone know the colour of [FeCl4]-
    can't find this particular one in any of my notes or textbooks
    I think it's yellow.
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    (Original post by Arab_Empress)
    Why does red light get reflected if blue light is absorbed?
    It's just frequencies of light,
    I think it goes from red to blue to UV etc
    They're just opposite ends of the visible light frequencies
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    (Original post by Arab_Empress)
    Why does red light get reflected if blue light is absorbed?
    It doesn't all the time, it depends on what compound it is, as each TM metal has a different number of outer 3d electrons so can excite to different levels so will give out light of a range of frequencies

    AHH alevel physics helps here
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    (Original post by Sheldon)
    Thanks a lot both of you, Much appreciated

    Any chance you can help me with
    Question 8c

    http://store.aqa.org.uk/qual/gce/pdf...W-QP-JAN10.PDF
    especially the 1/4 bit

    I am rubbish at calculations
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    (Original post by jamest92)
    Personally i just wrote all the colours and equations out over and over again. Takes the piss but they've managed to stick so far

    You reckon it's do-able in a day?
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    (Original post by Somali-Pir8)
    does anyone know the colour of [FeCl4]-
    can't find this particular one in any of my notes or textbooks
    No need to know it.
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    (Original post by Sparkly-Star)
    Me too :love: I started with 15 for the same reason, I find 16 easier. Luckily I had to do tons of revision on chapter 15/16 for my ISA so I don't find them too bad.
    Yeah I don't think the difficulty will change a lot, the grade boundaries seem to stay around the same numbers. :yep:
    Hmm on another note, where are all the chem people? The bio thread was full!
    Hopefully the grade boundaries they stay like that or go even lower lol
    I think they are finally filtering into the thread, but it did take a long time for me to find this cause its not under CHEM5

    (Original post by Sparkly-Star)
    Has everyone memorized 15.4/15.5?
    I haven't learnt them, It's easier to learn how to balance half equations.

    Like for potassium manganate I learn MnO4- --> M2+ and then just balance it with H2O, H+ and e-, Its the same with dichromate ...

    Btw sorry for the late reply I have being trying to finish Chapter 16, which I've done now. And a random question, on 5e i) of JUN 10, how do you know the initial and final colours. Is it because all aqueous Cu2+ ions form hexa aqua ions? But what about the final colour....don't worry if you don't know
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    I hope we get analysis of iron tablets. :p:
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    understand the importance of variable oxidation states in
    catalysis; both heterogeneous and homogeneous catalysts'

    anyone give me help with this??
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    (Original post by Wish I Could Change This)
    You reckon it's do-able in a day?
    Dont see why not, what i did was pick a metal then write down all the different formuale and colours you need so hex aqua, OH- and NH3, OH- in excess, NH3 in excess, carbonate ions and Cl- for cobalt and copper, and just repeat them all over the page, turn over and do the next metal. Once you've done all 6 take a break and come back and try and do them from memory, just keep at it and it should click eventually.
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    (Original post by Gertius Maximus)
    understand the importance of variable oxidation states in
    catalysis; both heterogeneous and homogeneous catalysts'

    anyone give me help with this??
    I think all that means is be aware that the reason catalysts work is because of variable oxidation states meaning they can transport electrons
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    (Original post by NRican)
    Thanks a lot both of you, Much appreciated

    Any chance you can help me with
    Question 8c

    http://store.aqa.org.uk/qual/gce/pdf...W-QP-JAN10.PDF
    especially the 1/4 bit

    I am rubbish at calculations
    I have not checked the mark-scheme so i don't know if this is right but here is my attempt
    Attached Images
     
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    (Original post by jamest92)
    Dont see why not, what i did was pick a metal then write down all the different formuale and colours you need so hex aqua, OH- and NH3, OH- in excess, NH3 in excess, carbonate ions and Cl- for cobalt and copper, and just repeat them all over the page, turn over and do the next metal. Once you've done all 6 take a break and come back and try and do them from memory, just keep at it and it should click eventually.
    completely forgot we had to learn the Cl- as well, thanks. I WILL get this done, I have a fun day ahead of me...
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    (Original post by Sparkly-Star)
    No need to know it.
    why not
    we need to know all of the other reactions/colours


    (Original post by Tigerkins)
    I think it's yellow.
    cheers, just trying to memorise it all last minute
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    (Original post by Sheldon)
    Electron will absorb Photons of light, the gain energy equal to the energy the photon had according to E=hf
    when the electrons have this energy they enter an exited state where they move up the energy levels in the orbitals, after a given time they will de-excite fall down the levels and release photons of light, these will have a different frequency to the ones taken in as some energy was used going up the energy levels and as E-hf the frequency has to change. So in Transition metals they give out light in the visible part of the spectrum.
    It all depends on what frequency of light is given out because each colour has its won frequency.
    Thank you very much
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    (Original post by Wish I Could Change This)
    completely forgot we had to learn the Cl- as well, thanks. I WILL get this done, I have a fun day ahead of me...
    Good luck, i expect you to be able to rattle them all off from memory by tonight
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    (Original post by GoodOl'CharlieB)
    Hopefully the grade boundaries they stay like that or go even lower lol
    I think they are finally filtering into the thread, but it did take a long time for me to find this cause its not under CHEM5



    I haven't learnt them, It's easier to learn how to balance half equations.

    Like for potassium manganate I learn MnO4- --> M2+ and then just balance it with H2O, H+ and e-, Its the same with dichromate ...

    Btw sorry for the late reply I have being trying to finish Chapter 16, which I've done now. And a random question, on 5e i) of JUN 10, how do you know the initial and final colours. Is it because all aqueous Cu2+ ions form hexa aqua ions? But what about the final colour....don't worry if you don't know
    I can remember the balancing ones easily but the ones with e.g. H2O2 are a pain to remember. :p: I've finished chapter 15 then I'm gonna do 16. :p: Hmm I'm not sure about the answer to do that! It looks like something from unit 2. I don't know sorry.
 
 
 
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