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    (Original post by otrivine)
    Define:equivalence point (2)
    Equivalence point is the point in an acid-base titration where the pH is neutral due to equal concentrations of (H+) and (OH-). This is the point in the reaction where the volume of one solution has reacted completely with the volume of the other solution.

    What is the standard enthalpy change of hydration?
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    (Original post by Tobeadoc)
    Equivalence point is the point in an acid-base titration where the pH is neutral due to equal concentrations of (H+) and (OH-). This is the point in the reaction where the volume of one solution has reacted completely with the volume of the other solution.

    What is the standard enthalpy change of hydration?
    good,correct!


    It is the enthalpy change when 1 mole of a gaseous ion is dissolved in water to form 1 mole of aqueous ion under standard conditions which are 100Kpa, 298K and concentration of 1 mol dm-3
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    (Original post by otrivine)
    good,correct!


    It is the enthalpy change when 1 mole of a gaseous ion is dissolved in water to form 1 mole of aqueous ion under standard conditions which are 100Kpa, 298K and concentration of 1 mol dm-3
    Yeah that's fine, the definition I know is the same just slightly different, with isolated gaseous ions instead of 1 mole of gaseous ion.
    my turn
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    (Original post by Tobeadoc)
    Yeah that's fine, the definition I know is the same just slightly different, with isolated gaseous ions instead of 1 mole of gaseous ion.
    my turn
    Yes



    Define: bidedate ligand (2)
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    (Original post by otrivine)
    Yes



    Define: bidedate ligand (2)
    A bidentate ligand is a ligand that has the ability to donate two lone pairs of electrons to form two dative covalent bonds(coordinate bonds) with the central metal ion.
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    (Original post by Tobeadoc)
    A bidentate ligand is a ligand that has the ability to donate two lone pairs of electrons to form two dative covalent bonds(coordinate bonds) with the central metal ion.
    Good answer


    My turn
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    (Original post by otrivine)
    Good answer


    My turn
    [Co(h20)6]^2+ +4Cl- <~> [CoCl4]^2- + 6H2O

    The above equilibrium was placed in a beaker of ice resulting in the colour change of blue to pink. On heating the solution turned blue. Is the reaction endo/exothermic? Explain.
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    (Original post by Tobeadoc)
    [Co(h20)6]^2+ +4Cl- <~> [CoCl4]^2- + 6H2O

    The above equilibrium was placed in a beaker of ice resulting in the colour change of blue to pink. On heating the solution turned blue. Is the reaction endo/exothermic? Explain.
    The reaction is exothermic because forward reaction colour chanes from blue to pink so equilibrium favours left as forward is exothermic
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    Been waiting for one of these to pop up for ages
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    (Original post by otrivine)
    The reaction is exothermic because forward reaction colour chanes from blue to pink so equilibrium favours left as forward is eothermic
    not going to get the mark for eothermic. The forward reaction is....
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    (Original post by Tobeadoc)
    not going to get the mark for eothermic. The forward reaction is....
    IS exothermic, I said that!
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    (Original post by otrivine)
    IS exothermic, I said that!
    Your answer is incorrect. I was giving you the benefit of the doubt...thanks for the neg. Anyway an increase in temperature causes the equilibrium to shift to the right, thus the forward reaction is endothermic. Remember [Co(h20)6]2+ is pink and the cobalt chloride is blue.
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    (Original post by Tobeadoc)
    Your answer is incorrect. I was giving you the benefit of the doubt...thanks for the neg. Anyway an increase in temperature causes the equilibrium to shift to the right, thus the forward reaction is endothermic. Remember [Co(h20)6]2+ is pink and the cobalt chloride is blue.
    Sorry for the neg, it was accident neg me back ! sorry


    oh i see thanks


    Suggest the process of which a ppt is formed by a halogen (1)
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    (Original post by Tobeadoc)
    Your answer is incorrect. I was giving you the benefit of the doubt...thanks for the neg. Anyway an increase in temperature causes the equilibrium to shift to the right, thus the forward reaction is endothermic. Remember [Co(h20)6]2+ is pink and the cobalt chloride is blue.
    but in your question you said blue to pink? it should be pink to blue?
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    (Original post by otrivine)
    but in your question you said blue to pink? it should be pink to blue?

    Question: [Co(h20)6]^2+ +4Cl- <~> [CoCl4]^2- + 6H2O


    The above equilibrium was placed in a beaker of ice resulting in the colour change of blue to pink. On heating the solution turned blue. Is the reaction endo/exothermic? Explain.

    Initially the colour of the solution is blue, then when placed in a colder environment the equilibrium moves to the left as there is a colour change to pink. This tells us that to the left is exothermic. When in warmer conditions the equilibrium moves to the right, resulting in reformation of the blue colour, this tells us that to the right is endothermic.
    In fairness I should have specified in the question that it was the forward reaction that was the answer.

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    (Original post by Tobeadoc)

    Question: [Co(h20)6]^2+ +4Cl- <~> [CoCl4]^2- + 6H2O


    The above equilibrium was placed in a beaker of ice resulting in the colour change of blue to pink. On heating the solution turned blue. Is the reaction endo/exothermic? Explain.

    Initially the colour of the solution is blue, then when placed in a colder environment the equilibrium moves to the left as there is a colour change to pink. This tells us that to the left is exothermic. When in warmer conditions the equilibrium moves to the right, resulting in reformation of the blue colour, this tells us that to the right is endothermic.
    In fairness I should have specified in the question that it was the forward reaction that was the answer.

    can I have another question , I think that question put me off a bit!
    please neg me, so sorry I neg you
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    (Original post by otrivine)
    can I have another question , I think that question put me off a bit!
    please neg me, so sorry I neg you
    haha no worries. What was the answer to the halogen ppt?

    A solution of NH3 was slowly added to an aq solution containing cu2+ ions until the NH3 was in excess. Initially a pale blue ppt forms, which then is followed by the formation of a dark blue solution.

    What is the pale blue? eqn for formation? what complex ion is formed??
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    (Original post by Tobeadoc)
    haha no worries. What was the answer to the halogen ppt?

    A solution of NH3 was slowly added to an aq solution containing cu2+ ions until the NH3 was in excess. Initially a pale blue ppt forms, which then is followed by the formation of a dark blue solution.

    What is the pale blue? eqn for formation? what complex ion is formed??
    its Precipitate reaction.


    Firstly, the aqueuous NaOH is used

    Cu2+ (aq) + 2OH-(aq) ---> Cu(OH)2 (s)
    Pale blue solution Pale blue Precipitate

    Then an excess NH3 is added in order to neutralise the precipitate that was formed , the Cu(OH)2(s).

    When NH3 is added a complex ion is formed and has undergone a ligand substitution,

    [Cu(H2O)6]^2+ + 4NH3 equilibrium sign [Cu(NH3)4(H2O)2]^2+ + 4H20
    Pale blue solution deep blue solution
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    (Original post by otrivine)
    its Precipitate reaction.


    Firstly, the aqueuous NaOH is used

    Cu2+ (aq) + 2OH-(aq) ---> Cu(OH)2 (s)
    Pale blue solution Pale blue Precipitate

    Then an excess NH3 is added in order to neutralise the precipitate that was formed , the Cu(OH)2(s).

    When NH3 is added a complex ion is formed and has undergone a ligand substitution,

    [Cu(H2O)6]^2+ + 4NH3 equilibrium sign [Cu(NH3)4(H2O)2]^2+ + 4H20
    Pale blue solution deep blue solution
    yeah thats correct!! my turn
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    (Original post by Tobeadoc)
    yeah thats correct!! my turn

    A moss killer contains iron(II) sulphate.
    Some of the iron(II) sulphate gets oxidised to form iron(III) sulphate. During the oxidation iron(II) ions, Fe2+, react with oxygen, O2, and hydrogen ions to make water and iron(III) ions, Fe3+.


    construct the equation for the oxidation of acidified iron(II) ions by oxygen (2)
 
 
 
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