1. The problem statement, all variables and given/known data So we know Enthalpy under constant Pressure and Internal Energy under Constant Volume. By H = U + dPdV U= I + W W= -PdV under Isobaric conditions H = I -PdV + dPdV = U Enthalpy = Internal Energy _________________________________________ Under Isochoric Conditions W= O because change in V =o so U = q + 0 Internal Energy = q But wouldnt Enthalpy also = q under constant volume since dPdV = 0 as well if volume isnt changing? 2. Relevant equations H = U + dPdV U= I + W W= -PdV 3. The attempt at a solution ( Outlined above) Am i confusing the dPdV specific to enthalpy and PdV in work?