A welder using a tank of volume 7.30×10−2 m3 fills it with oxygen (with a molar mass of 32.0 g/mol) at a gauge pressure of 2.85×105 Pa and temperature of 37.6 ∘C. The tank has a small leak, and in time some of the oxygen leaks out. On a day when the temperature is 20.0 ∘C, the gauge pressure of the oxygen in the tank is 2.00×105 Pa. Part a -Find the initial mass of oxygen. Part b- Find the mass of oxygen that has leaked out.