A cylinder has a capacity of 300 cubic feet and contains oxygen at a pressure of 3.1 mpa and temperature of 18 deg c. the stop valve is opened and some of the gas is used. if the pressure and temperature of the gas left in the cylinder falls to 1.7mpa and 15 deg c determine, oxygen has molecular weight of 32 (kg/kmol). what is the specific gas constant for this gas in (j/kg-k), initial mass of the O2, final mass of O2, chang in total internal energy contained in the cylinder.