0.5 kg of saturated vapor (H2O) at 1.5 bars is contained in a piston-cylinder device. Heat transfer in the amount of 150 kJ to the steam occurs and some work is done on the steam by a impellor. At the end of this process the steam is at 1.5 bars and 400 C. Assuming the pressure of the steam was constant throughout the process determine the work transfer by the impellor.