A cylinder 1.00 m tall with inside diameter 0.120 m is used to hold propane gas (molar mass 44.1 g/mol) for use in a barbecue. It is initially filled with gas until the gauge pressure is 1.30 X 106 Pa and the temperature is 22.0oC. The temperature of the gas remains constant as it is partially emptied out of the tank, until the gauge pressure is 2.50 X l05 Pa. Calculate the mass of propane that has been used.