Question

Consider the reaction

2H2O(g) → 2H2(g) + O2(g) ΔH = +483.60 kJ/mol

at a certain temperature. If the increase in volume is 42.7 L against an external pressure of 1.00 atm, calculate ΔU for this reaction. (The conversion factor is 1 L · atm = 101.3 J.)

Answer 1

du = dq + dw

du = +483.6 KJ/Mol + 42.7 L * 1*10^5

Answer 2

The above by Cameron is correct EXCEPT the dw portion.
In L*atm that is 42.7 L x 1 atm. Convert that to J by 42.7 x 1 x 101.3 = dW.