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    (Original post by otrivine)
    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)
    Fe 2+ being oxidised to Fe3+. Then O2 is reduced to O2-so overall -4. So then overall:

    4Fe2+ +4H+ +O2> 4Fe3+ + 2H2O
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    (Original post by Tobeadoc)
    Fe 2+ being oxidised to Fe3+. Then O2 is reduced to O2-so overall -4. So then overall:

    4Fe2+ +4H+ +O2> 4Fe3+ + 2H2O
    yup !

    my turn
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    (Original post by otrivine)
    yup !

    my turn
    what is a homogenous equilibrium?
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    (Original post by Tobeadoc)
    what is a homogenous equilibrium?
    is an equilibrium in which the species that make up the reactant and products are in the same physical states.
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    (Original post by otrivine)
    is an equilibrium in which the species that make up the reactant and products are in the same physical states.
    correct my turn
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    (Original post by Tobeadoc)
    correct my turn
    Why is it impossible to measure the lattice enthalpy directly (2)
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    (Original post by otrivine)
    Why is it impossible to measure the lattice enthalpy directly (2)
    It would be impossible to react the gaseous ions together, as formation of them and then causing them to react would require too high energies.
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    (Original post by Tobeadoc)
    It would be impossible to react the gaseous ions together, as formation of them and then causing them to react would require too high energies.
    Not quite, no, its because it is impossible to form 1 mole of an ionic compound from its gaseous ions

    my turn
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    (Original post by otrivine)
    Not quite, no, its because it is impossible to form 1 mole of an ionic compound from its gaseous ions

    my turn
    when is a dynamic equilibrium established?
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    (Original post by Tobeadoc)
    when is a dynamic equilibrium established?
    In a closed system and that the rate of the forward reaction is the same as the rate of the reverse reaction.

    There is a constant concentration of both reactants and products
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    (Original post by otrivine)
    In a closed system and that the rate of the forward reaction is the same as the rate of the reverse reaction.

    There is a constant concentration of both reactants and products
    correct! my turn
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    (Original post by Tobeadoc)
    correct! my turn


    Artists between the 13th and the 19th Centuries used a green pigment called verdigris. The artists made the pigment by hanging copper foil over boiling vinegar.
    During the preparation of verdigris, copper atoms are oxidised to copper(II) ions.

    i) Write the oxidation half equation for the conversion of copper atoms into copper(II) ions.

    (ii) The reduction half equation that takes place is as follows.
    O2(g) + 4H+(aq) + 4e– ---> 2H2O(l)
    Construct the equation for the redox reaction between copper, oxygen and hydrogen ions.
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    (Original post by otrivine)


    Artists between the 13th and the 19th Centuries used a green pigment called verdigris. The artists made the pigment by hanging copper foil over boiling vinegar.
    During the preparation of verdigris, copper atoms are oxidised to copper(II) ions.

    i) Write the oxidation half equation for the conversion of copper atoms into copper(II) ions.

    (ii) The reduction half equation that takes place is as follows.
    O2(g) + 4H+(aq) + 4e– ---> 2H2O(l)
    Construct the equation for the redox reaction between copper, oxygen and hydrogen ions.
    The equation for the oxidation of copper atoms: Cu->Cu2+ + 2e-
    O2(g) + 4H+(aq) + 2Cu <~> 2H2O + 2Cu2+
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    (Original post by Tobeadoc)
    The equation for the oxidation of copper atoms: Cu->Cu2+ + 2e-
    O2(g) + 4H+(aq) + 2Cu <~> 2H2O + 2Cu2+
    Good


    my turn
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    (Original post by otrivine)
    Good


    my turn
    Plan an experiment that a student could carry out to measure the enthalpy change of neutralisation? (6)
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    (Original post by Tobeadoc)
    Plan an experiment that a student could carry out to measure the enthalpy change of neutralisation? (6)
    Okay,

    Firstly, in order to carry out the experiment, you would need to use a polystrene cup or a bombcalorimeter. Polystrene cup is quick but can lead to unreliable data.
    Using a polysterene cup for example you pour the solution into the cup and add any solid to the solution for a reaction to take place, you put a thermometer in the cup in order to detect the temperature. Also, use known concentration of the solution for example could be water, such as add 100cm3 of water. Record the temperature, if temperature is rising the reaction would be exothermic or if reaction is decreasing it would be endothermic. Then calculate the energy in joules that was released during the experiment

    formula is energy= 4.18 (specific heat capacity) x volume x temperature change


    then you get the answer in joules, always convert into Kj in order to get accurate results.

    Then you calculate the number of moles , it could be the solid that you added into the solution, and formula is moles =mass/Molar mass of that substance/compound

    then you work out the enthalpy change of neutralisation= energy in Kj divided by the number of moles and this gives the enthalpy change of neutralisation value. Most cases the value is exothermic for neutralsiation.
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    The questions in this paper are so nasty. One of my classmates told me she saw a 20-marker! The max you would get previously was like 12 marks but even that was a juicy NMR question that was satisfying.

    Edit: reason for negs?
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    (Original post by uttamo)
    The questions in this paper are so nasty. One of my classmates told me she saw a 20-marker! The max you would get previously was like 12 marks but even that was a juicy NMR question that was satisfying.
    Hi want to revise F325
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    (Original post by otrivine)
    Hi want to revise F325
    Your sentence doesn't make sense, I don't know what you're saying lol
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    (Original post by uttamo)
    Your sentence doesn't make sense, I don't know what you're saying lol
    Asking each other questions?
 
 
 
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