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    I am usually ok at answering these questions, but this one is different as it is asking me to find the enthalpy change per mole of the element/compound in the solution rather than the one being added, and it is really confusing me.

    The question: Addition of 1.6g of Magnesium to 100cm3 of 2M copper sulphate solution raised the temperature by 45'C. Find the enthalpy change per mole of copper sulphate in the reaction.

    I would really appreciate some help on this. Kind regards 👍🏻
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    (Original post by Sam00)
    I am usually ok at answering these questions, but this one is different as it is asking me to find the enthalpy change per mole of the element/compound in the solution rather than the one being added, and it is really confusing me.

    The question: Addition of 1.6g of Magnesium to 100cm3 of 2M copper sulphate solution raised the temperature by 45'C. Find the enthalpy change per mole of copper sulphate in the reaction.

    I would really appreciate some help on this. Kind regards 👍🏻
    moles of Mg = mass/Ar
    moles of copper sulfate = molarity x volume

    which ever is the smaller is the limiting reagent

    E = mcΔT

    energy per mol = energy/moles of limiting reagent
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    (Original post by charco)
    moles of Mg = mass/Ar
    moles of copper sulfate = molarity x volume

    which ever is the smaller is the limiting reagent

    E = mcΔT

    energy per mol = energy/moles of limiting reagent
    Thank you, I was dividing the mass 100 by the Ar 95.6, then divided the energy 18810 by the former figure, getting the wrong answer.

    Could I just ask you to explain why it's different working for finding the moles of Mg and CuS?
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    (Original post by Sam00)
    Thank you, I was dividing the mass 100 by the Ar 95.6, then divided the energy 18810 by the former figure, getting the wrong answer.

    Could I just ask you to explain why it's different working for finding the moles of Mg and CuS?
    It isn't different. You just have to focus only on what is actually reacting.

    copper sulfate = CuSO4
 
 
 
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