100 kg of R-134a at 280 kPa are contained in a piston-cylinder device whose volume is 8.672 m3. The piston is now moved until the volume is one-half its original size. This is done such that the pressure of the R-134a does not change. Determine the final temperature and the change in the total internal energy of the R-134a. (Round the final answers to two decimal places.)