Chemistry
posted by DC .
I would really appreciate some help with this thermochemistry problem! I'm really confused as to why I keep getting the wrong answers... I have gotten w=1.305kj and energy change = 78.13kj... both of which were marked wrong. Here's the question:
The oxidation of copper(I) oxide, Cu2O(s), to copper(II) oxide, CuO(s), is an exothermic process,
2 Cu2O + O2 > 4CuO
The change in enthalpy upon reaction of 75.30 g of Cu2O(s) is 76.83 kJ. Calculate the work, w, and energy change, ΔUrxn, when 75.30 g of Cu2O(s) is oxidized at a constant pressure of 1.00 bar and a constant temperature of 25°C.
Additional Details
Useful equations
Ideal Gas: PV = nRT
Work: w = –PΔV
Energy Change: ΔUrxn = ΔHrxn – PΔV
Thank you in advance! :)

If you had shown your work perhaps could have found the error. When you did pdV did you leave that in L*atm or did you convert that to kJ? Why not wshow your work and let us look at it?