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    Please can someone explain to me how question 2.) C.) ii.) works.

    Much appreciated!
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    (Original post by thelion0)
    Please can someone explain to me how question 2.) C.) ii.) works.

    Much appreciated!
    It's just the difference between the electrode potentials of the two half cells
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    (Original post by charco)
    It's just the difference between the electrode potentials of the two half cells
    you answered the wrong question.
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    (Original post by thelion0)
    you answered the wrong question.
    ahhh yes, so I did

    2Cii) Work out the moles of thiosulphate: 0.0205 * 0.2

    Using the equations:

    mol thiosulphate/2 = moles of iodine
    moles of iodine * 2 = moles of copper

    Hence moles of thiosulphate = moles of copper ions.

    To find the total moles of copper ions multiply by 10 to scale up to the 250ml solution.

    Then moles of copper ==> mass of copper

    Then percentage = 100 * mass of copper/mass of sample
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    (Original post by charco)
    ahhh yes, so I did

    2Cii) Work out the moles of thiosulphate: 0.0205 * 0.2

    Using the equations:

    mol thiosulphate/2 = moles of iodine
    moles of iodine * 2 = moles of copper

    Hence moles of thiosulphate = moles of copper ions.

    To find the total moles of copper ions multiply by 10 to scale up to the 250ml solution.

    Then moles of copper ==> mass of copper

    Then percentage = 100 * mass of copper/mass of sample
    haha! thank you very much I understand it now. its the calculations that get me each time..

 
 
 
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