Nitrogen at 600 kPa, 127?C is in a 0.5-m3 insulated tank connected to a pipe with a valve to a second insulated initially empty tank of volume 0.25 m3, shown in Fig. P6.158. The valve is opened, and the nitrogen fills both tanks at a uniform state. Find the final pressure and temperature and the entropy generation this process causes. Why is the process irreversible?