• Question: As we need Oxygen to breathe and survive, but the air is only 20.94% Oxygen, yet it is 78.08% nitrogen. What happens to the nitrogen we inhale? Does it just get exhale instant ly or dies anyhting special happen?

    Asked by IntellTanito to Sebastian, Lee, Jennifer, Fiona on 14 Mar 2019.
    • Photo: Fiona Scott

      Fiona Scott answered on 14 Mar 2019:


      Great question. You’re right. Our bodies don’t absorb the nitrogen gas, only the oxygen gas, so we just breathe it out again. Nitrogen is instead “fixed” by bacteria and plants i.e. they convert nitrogen gas (N2) into more useful things like ammonia (NH3) and amino acids etc.

    • Photo: Sebastian Cosgrove

      Sebastian Cosgrove answered on 14 Mar 2019:


      Couldn’t have said it better than Fiona! Nitrogen is so unreactive that we actually use it in chemistry to generate unreactive atmospheres! This allows us to do reactions that might react with oxygen or with the really small amount of water vapour in the air. If we exclude the rest of the gases in the atmosphere and just use nitrogen then we can do what we call ‘inert’ reactions, where unstable chemicals don’t do any reactions with the nitrogen because it is so unreactive!

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