chemistry
posted by Dana on .
Calculate the expansion work done when 50 g of water is electrolysed under constant pressure at 25C

10KJ

10KJ

how did u get 10 kj

Please show procedures

I don't no the answer

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.

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