Can Oxygen and nitrogen gas be separated physically?

Answer 1

1. Process of Turning Air Into Liquid Oxygen & NitrogenTwo Different Elements with Different Boiling Points
2. Air is made up of 80 percent nitrogen and 20 percent oxygen. The boiling points of these elements are different: oxygen's boiling point is minus 297 degrees Fahrenheit and nitrogen's is minus 320 degrees Fahrenheit. This physical property, the different boiling points, is used to separate them. Basically, air is cooled to the point that oxygen becomes liquid. The liquefied oxygen is easily separated from the remaining gas and the remaining air is further cooled down to produce liquid nitrogen. The Linde Process
3. The Linde Process uses the Joule-Thomson effect to liquefy nitrogen and oxygen from air. You can experience this effect in your household when the contents of a pressurized spray can are quickly released. You will notice that as you let the compressed gas leave the can, the can feels cold. The Linde Process uses the Joule-Thomson effect iteratively (compressing and expanding the gas repeatedly), which eventually causes the gas to reach its boiling point, become a liquid and be separated from the other gases.
   The thermodynamic explanation is this: as gas expands, the molecules gain energy as potential energy and they lose energy as kinetic energy. A decrease in kinetic energy means that the molecules will move slower and the collisions between molecules are less frequent, hence the temperature is lower. After this decrease, it is important for the system to be isolated so it cannot exchange heat with its surroundings. Not Only nitrogen and Oxygen
4. Air also contains argon and other noble gases in minor traces such as neon, helium, krypton and xenon. You will notice that companies that sell nitrogen and oxygen sell argon as well. Air, of course, also contains carbon dioxide and hydrogen, but these are obtained by other industrial processes.