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    how much ums is this unit out of?
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    (Original post by NRican)
    What colour is [Cr(NH3)6)3+ I am pretty sure the NT book has it wrong?
    (Original post by cheeseisnice)
    I thought it was purple. What does the NT book say?
    It is purple (solution), I think the book refers to "Ruby Red" or something like that.. Both will get you the marks though.
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    (Original post by oloyeded020)
    how much ums is this unit out of?
    Out of 120
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    Nearly done with learning my transition metal colours. :jive:
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    (Original post by adam1232)
    hey could anyone help me with redox equations im just not sure when you include only one reagent and product for example in the specimen paper,

    3 (a)An aqueous solution of sulfur dioxide was reacted in separate experiments as follows.

    Reaction 1 with HgO
    H2O + SO2 + HgO ? H2SO4 + Hg

    Reaction 2 with chlorine
    2H2O + SO2 + Cl2 ? H2SO4 + 2HCl

    (ii) Show, by writing a half-equation, that this oxidising agent in reaction 1 is an
    electron acceptor.
    ................................ ................................ ................................ ................................ ..
    (iii) Write a half-equation for the oxidation process occurring in reaction 2.
    ................................ ................................ ................................ ................................ ..
    (iv) Write a half-equation for the reduction process occurring in reaction 2.
    ................................ ................................ ................................ ................................ ..

    the answer for ii is Hg 2+ + 2e- -------> Hg

    the answer for iii is 2H2O + SO2 ? H2SO4 + 2e-

    why dosnt the oxygen on the Hg come into the half equation?

    Thanks
    pleaseeeeeeeeeee help meeeeeeeeeeeeeee
    I think its considered a "spectator ion" as in its not involved in the redox equation because its oxidation state doesn't change ? could be wrong though :/
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    (Original post by BethBeth)
    I don't like enthalpy of sublimation - never heard of it referred to as that, stick with enthalpy of atomisation and you will definitely get the marks..

    I suppose it is bond dissociation in the case of 1/2Cl2(g) ---> Cl(g)
    But if you got this in a Born-Haber Cycle of MgCl2 for instance you would have to times enthalpy of atomisation by two.

    Enthalpy of atomisation = Enthalpy change attending the formation of one mole of gaseous atoms from the element in it's standard state.
    Best be careful and stick to one definition.
    okay thanks for the help!
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    (Original post by teddyWS)
    okay thanks for the help!
    No problem! As you can probably tell I'm getting slightly distracted from hardcore revision now
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    (Original post by Sparkly-Star)
    Nearly done with learning my transition metal colours. :jive:
    Congrats ... lol
    I'm coming to the end of Chapter 15 ...i nearly died :facepalm: :cry:
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    (Original post by xX.Sabeel.Xx)
    yeah we do:

    Reduction: O2(g) + 2H2O(l)+ 4e- > 4OH-(aq)

    Oxidation: 2H2(g) + 4OH-(aq) > 4H2O(l) + 4e-

    Overall: 2H2(g) + O2(g) > 2H2O(l)
    Thank youu
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    (Original post by GoodOl'CharlieB)
    Congrats ... lol
    I'm coming to the end of Chapter 15 ...i nearly died :facepalm: :cry:
    :cry2: :hugs: Aww, I know how you feel. :cry2: :hugs: We'll get there.
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    (Original post by Raimu)
    Co(H2O)6 + 4Cl- ----> Co(Cl4)2- + 6H2O
    thanks, and what colour is it?
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    Why does Chromium (III) change colours so many times. It's making life difficult for us... =/
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    (Original post by Wish I Could Change This)
    thanks, and what colour is it?
    Pale blue solution.
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    (Original post by Sparkly-Star)
    Why does Chromium (III) change colours so many times. It's making life difficult for us... =/
    I thought it only has 2 colours? :/

    Purple solution, and green ppt
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    (Original post by Stirlo)
    I thought it only has 2 colours? :/

    Purple solution, and green ppt
    Well 3 colours, but what I meant was the formula changes so many times haha. :p:

    Edit:

    It's not so bad it goes from ppt, sol, ppt, sol, ppt. :p:
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    (Original post by adam1232)
    hey could anyone help me with redox equations im just not sure when you include only one reagent and product for example in the specimen paper,

    3 (a)An aqueous solution of sulfur dioxide was reacted in separate experiments as follows.

    Reaction 1 with HgO
    H2O + SO2 + HgO ? H2SO4 + Hg

    Reaction 2 with chlorine
    2H2O + SO2 + Cl2 ? H2SO4 + 2HCl

    (ii) Show, by writing a half-equation, that this oxidising agent in reaction 1 is an
    electron acceptor.
    ................................ ................................ ................................ ................................ ..
    (iii) Write a half-equation for the oxidation process occurring in reaction 2.
    ................................ ................................ ................................ ................................ ..
    (iv) Write a half-equation for the reduction process occurring in reaction 2.
    ................................ ................................ ................................ ................................ ..

    the answer for ii is Hg 2+ + 2e- -------> Hg

    the answer for iii is 2H2O + SO2 ? H2SO4 + 2e-

    why dosnt the oxygen on the Hg come into the half equation?

    Thanks
    pleaseeeeeeeeeee help meeeeeeeeeeeeeee
    (Original post by HMcVicar)
    x
    Actually it should be included since the oxygen originates from a water molecule so the species has changed (ionic equations aren't just about oxidation state though it may seem like it after all the redox stuff that has been shoved down our throats for this unit lol, it could also include a change is state for example).

    I'm thinking it's a typical specimen paper error since they don't put much effort into those and mistakes often crop up.

    It should be:

    2H+ + 2e- + HgO ---> Hg + H2O

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    When writing the conventional cell rep. e.g in JAN 10 question 3C
    http://store.aqa.org.uk/qual/gce/pdf...W-QP-JAN10.PDF


    How do you know if to write the OH- before the H2O or H2O before the OH- ? or does it not matter

    In the mark scheme it says h20 not needed, but still....

    Thank you
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    Hey people does anyone else think the specimen paper has a mistake in it:

    MS http://store.aqa.org.uk/qual/gce/pdf...5-W-SMS-07.PDF

    QP http://store.aqa.org.uk/qual/gce/pdf...5-W-SMS-07.PDF

    Question 3iii
    Should it not be 2H2O + SO2 + 2H+ --> H2SO4 +2e-
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    cannot wait to never have to do ****ty chemistry ever again!!
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    (Original post by Sheldon)
    Hey people does anyone else think the specimen paper has a mistake in it:

    MS http://store.aqa.org.uk/qual/gce/pdf...5-W-SMS-07.PDF

    QP http://store.aqa.org.uk/qual/gce/pdf...5-W-SMS-07.PDF

    Question 3iii
    Should it not be 2H2O + SO2 + 2H+ --> H2SO4 +2e-
    But that would not balance the hydrogens, you'll have 6 on the right and 2 on the left.
    The charges are also not balanced...
 
 
 
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