According to Thermodynamics First Law, ΔU=ΔQ−ΔW, where ΔU is Change in Internal Energy (kJ/kg), ΔQ is the amount of heat received (in kJ/kg), and ΔW is work done (in kJ/kg). The units will be kJ for all three thermodynamic property is specific values (independent of mass) are not being considered. Further, for Isobaric process (the thermodynamic process in which pressure remains constant), the relation for work done is ΔWisobaric=p×(V2−V1). Here, the change in internal energy is to be obtained in kJ. So, Q=10kg×5‌kJ∕kg=50 kJ ; and W=p×∆V=100‌kPa×0.2 m3=20 kJ Thus, U=ΔQ−∆W=50−20=30 kJ