Answer
The process is detailed below.
Work Step by Step
To obtain elemental nitrogen, air is cooled below $-196^{\circ}C$, which causes it to liquefy. When the liquid air is warmed slightly, the nitrogen boils off, leaving liquid oxygen (which boils at the higher temperature of $-183^{\circ}C$ ). Passing the vaporized gas over hot copper metal purifies the nitrogen by removing residual oxygen (which reacts with the copper to form CuO). Nitrogen gas can also be separated from the other atmospheric gases by passing air through certain silicate materials called zeolites, which have channels of just the right diameter to separate gas molecules of different size.
