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    It had a coordination no. of 6, but with three en (you count each coordinate bond separate). No, I don't remember it specifically asking us that. I did overkill by drawing it all proper, then again skeletal to make it look prettier :3


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    (Original post by Fergy94)
    what was the co-ordination number? was it 3 for the equation for en? with a 2+ charge?
    coordination number 6 as it had 4h20's and 2 nitrogens from the en, i think the product for the equation was [co(h20)4en]2+ so the charge i think is 2+
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    (Original post by fajitamunch)
    I swear for all the colour changes section it didn't say observation? It only said starting colour, ending colour and equation... So ppt or solution wasn't needed?
    It Deffinately said state what you observe..
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    (Original post by xChristophx)
    Quoting's not functionig in my browser for some reason, so apologies:




    I got [Co(Cl)3(NH3)]-

    Because the ratio is 3:1, so one Co will have three Cl- ions on it. I decided to put on ammonia because I wasn't sure if three ammonias would fit onto the Co ion, considering its already got three Cl- ions on it.
    My chemistry teacher said that the AgCl would only form with Cl ions ionically bonded to the complex ie. [Co(NH3)6]Cl3 not with Chorine ligands within the complex. He knows the AQA & their markschemes like the back of his hand so I can't believe he would be wrong about this. Just thought I'd add to the confusion.
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    (Original post by qwerty1D)
    coordination number 6 as it had 4h20's and 2 nitrogens from the en, i think the product for the equation was [co(h20)4en]2+ so the charge i think is 2+
    It was [co(en)3]2+
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    (Original post by qwerty1D)
    i know i quoted the quote instead of the original post my apologies
    No worries haha.
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    (Original post by frogs r everywhere)
    It was [co(en)3]2+
    2+ ions form [M(h20)4en]2+ as far i got taught?
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    (Original post by frogs r everywhere)
    It was [co(en)3]2+
    I got exactly that!

    doesn't that mean a co-ordination number of 3 though? Or is it because it's a bidentate and makes 6?
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    Any A2 CHEM brahs got any resource/book/advice for current year 12 brah, dieing to start soon want an A tanks plz xx
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    Anyone get 19 kelvin for the one you had to use deltaH= mcdeltaT???
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    (Original post by UKBrah)
    Any A2 CHEM brahs got any resource/book/advice for current year 12 brah, dieing to start soon want an A tanks plz xx
    Brah Brah Brah

    What do you need brah?
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    (Original post by UKBrah)
    Any A2 CHEM brahs got any resource/book/advice for current year 12 brah, dieing to start soon want an A tanks plz xx
    get a text book and study....

    brah.
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    When will the mark scheme be done by?
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    Did anyone happen to get a copy of the paper? Might help clear up some confusion :P
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    (Original post by UKBrah)
    Any A2 CHEM brahs got any resource/book/advice for current year 12 brah, dieing to start soon want an A tanks plz xx
    I don't know any undergarments that study A2 chemistry. You could always try Next or Ann Summers or something, if you're looking for 'brahs'. :teehee:

    On a more serious note, there is an old thread where this person posted all their chemistry notes and are really good to look at. Oh, and advice? Expect the unexpected. That's what this exam taught me!
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    (Original post by qwerty1D)
    i know i quoted the quote instead of the original post my apologies
    Hey what did u get for the last question?


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    I wish someone had the exam waa!!! Any grade boundaries predictions? I literally think this paper was harder than any ever.. june 11 wasnt too bad and that was 71 for an A.. its got to be around 69!

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    (Original post by extons)
    The reason for not using KCl or whatever as a salt bridge, I said that the Cl- ions would react with the copper electrode to form copper chloride. Is this OK?

    It's only because in so many of the mark schemes the reason FOR using a specific salt bridge is because it 'doesn't react with the electrode'.

    Just curious. Thanks.
    That's what I said
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    I got the paper can anyone answer the questions for Aqa Chem 5 Unoffical mark scheme
    1(a) Define the term lattice enthalphy of dissociation.
    1(b) Lattice enthalapy can be calculated theoretically using a perfect ionic model
    Explain the meaning of the term perfect ionic model
    1(c) Suggest two properties of ions that influence the value of a lattice enthalpy calculated using a perfect ionic model
    1(D) Use the data in the table to calculate a value for the lattice entalapy ofdissociation for silver chloride
    Enthalpy change value/kjmol-1
    Enthalpy of atomisation for silver +289
    First ionisation energy for silver +732
    Enthalpy of atomisation for chlorine +121
    Electron affinity for chlorine -364
    Enthalpy of formation for silver chloride -127

    1(e) Predict whether the magnitude of the lattice enthalpy of dissociation that you have calculated in part (d) will be less than, equal to or greater than the value that is obtained from a perfect ionic model. Explain your answer
    Prediction compared with ionic model......
    Explanation

    2 The enthalpy of hydration for the chloride ion is -364kjmol-1 and that for the bromide ion is -335kjmol-1
    2(a) By describing the nature of the attraction forces involved, explain why the value for the enthalpy of hydration for the chloride ion is more negative than that for the bromide ion.

    2(b) The enthalpy of hydration for the potassium ion is -322kjmol-1. The lattice enthalpy of dissociation for potassium bromide is +670kjmol-1
    Calculate the enthalpy of soloution for potassium bromide.

    2(c) The enthalpy of solution for potassium chloride is +17.2kjmol-1.
    Explain why the free-energy change for the dissolving of potassium chloride in water is negative, even though the enthalpy change is positive.

    2(c)ii A solution is formed when 5.00g of potassium chloride are dissolved in 20.0g of water.
    The initail temp of the water is 298k.
    Calculate the final temp of the solution.
    In your calculation, assume that only the 20.0g of water changes in temp and that the specific heat capacity of water in 4.18jk-1g-1.

    3(a)(i) Explain in terms of molecules why the entropy is zero when the temp is zero Kelvin.


    3(a) (ii) Explain in terms of molecules why the first part of the graph in figure 1 is a line that slopes up from the origin.

    3(a) (iii) On Fig 1 mark on the app axis the boiling point (Tb) of substance x
    3(a) iv In terms of the behaviour of molecules explain why L2 IS LONGER than L1 in FIG 1
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    (Original post by naeemkhan12)
    I got the paper can anyone answer the questions for Aqa Chem 5 Unoffical mark scheme
    1(a) Define the term lattice enthalphy of dissociation.
    1(b) Lattice enthalapy can be calculated theoretically using a perfect ionic model
    Explain the meaning of the term perfect ionic model
    1(c) Suggest two properties of ions that influence the value of a lattice enthalpy calculated using a perfect ionic model
    1(D) Use the data in the table to calculate a value for the lattice entalapy ofdissociation for silver chloride
    Enthalpy change value/kjmol-1
    Enthalpy of atomisation for silver +289
    First ionisation energy for silver +732
    Enthalpy of atomisation for chlorine +121
    Electron affinity for chlorine -364
    Enthalpy of formation for silver chloride -127

    1(e) Predict whether the magnitude of the lattice enthalpy of dissociation that you have calculated in part (d) will be less than, equal to or greater than the value that is obtained from a perfect ionic model. Explain your answer
    Prediction compared with ionic model......
    Explanation

    2 The enthalpy of hydration for the chloride ion is -364kjmol-1 and that for the bromide ion is -335kjmol-1
    2(a) By describing the nature of the attraction forces involved, explain why the value for the enthalpy of hydration for the chloride ion is more negative than that for the bromide ion.

    2(b) The enthalpy of hydration for the potassium ion is -322kjmol-1. The lattice enthalpy of dissociation for potassium bromide is +670kjmol-1
    Calculate the enthalpy of soloution for potassium bromide.

    2(c) The enthalpy of solution for potassium chloride is +17.2kjmol-1.
    Explain why the free-energy change for the dissolving of potassium chloride in water is negative, even though the enthalpy change is positive.

    2(c)ii A solution is formed when 5.00g of potassium chloride are dissolved in 20.0g of water.
    The initail temp of the water is 298k.
    Calculate the final temp of the solution.
    In your calculation, assume that only the 20.0g of water changes in temp and that the specific heat capacity of water in 4.18jk-1g-1.

    3(a)(i) Explain in terms of molecules why the entropy is zero when the temp is zero Kelvin.


    3(a) (ii) Explain in terms of molecules why the first part of the graph in figure 1 is a line that slopes up from the origin.

    3(a) (iii) On Fig 1 mark on the app axis the boiling point (Tb) of substance x
    3(a) iv In terms of the behaviour of molecules explain why L2 IS LONGER than L1 in FIG 1
    Is it possible for you to scan it instead?

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