In a closed container of volume 10-3 m3, O2 gas is filled at temperature 400 K and pressure 1.5 atm. A small hole is made in the container from which gas leaks out to open atmosphere. After sometime the temperature and pressure of container become equal to that of surrounding. The mass of gas (in grams) that leaks out from the container is ___________. (Atmospheric temperature = 300 K)