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chemistry

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Calculate the expansion work done when 50 g of water is electrolysed under constant pressure at 25C

  • chemistry - ,

    -10KJ

  • chemistry - ,

    -10KJ

  • chemistry - ,

    how did u get -10 kj

  • chemistry - ,

    Please show procedures

  • chemistry - ,

    I don't no the answer

  • chemistry - ,

    -10kJ because you have to consider the work due the H2 (-6,7kJ) and the work due the O2 produced (-3.3kJ) in the reaction.

  • chemistry - ,

    Here is the answer
    2H2O -------> O2 + 2H2
    2.7 mol 1,38 mol 2,7 mol

    mol H2O = 50g/18 g/mol = 2.7 mol

    for general eq -> w = - Pex.delta V
    Pex= external pressure
    delta V = Vfinal (V2) - V initial(V1)
    neglect the intial volume because the final volume (after the production of gas) is so much larger and delta V = Vf- Vi=Vf=nRT/Pex, then : W = -(n.R.T)
    wO2 = -(nxRxT)
    wO2 = 1,38 mol x 8,3145 J.K^-1.mol^-1 x 298 =-3,4 Kj
    same for calcualting O2 then wH2 = -6,8 kJ
    Wtotal = WO2 + WH2 = -3,4 Kj + (-6,8 Kj) = 10,2 Kj or 10 Kj

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