Air contains approximately 21 mol % oxygen and 79 mol % nitrogen. An engineer claims to have developed a continuous process in which air is first compressed to 2 bar and 25°C, and then isothermally expanded to atmospheric pressure through a secret device that has no moving parts and results in two gas streams. The first stream is said to contain 99 mol % oxygen, and the second stream contains only 5 mol % oxygen. Prove whether such a device is thermodynamically possible.