• Question: how is liquid nitrogen formed?

    Asked by Bassett to Frank on 12 Mar 2015.
    • Photo: Frank Longford

      Frank Longford answered on 12 Mar 2015:

      Basically you just need a freezer that goes down to around -215 degrees Celsius, a pressurised container and a load of air. Since air is 78% nitrogen, if you freeze a container of air (at -215 degrees C) then you’re already pretty close to what you want. The other gases in air can be separated off using “cryogenic distillation” by altering the pressure of your container.

      Actually we don’t make liquid nitrogen in the chemistry lab , but it is bought from a company and stored large containers on site to be used when needed.

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