Nitrogen Gives Life And Takes It Away

07/06/2019 Nitrogen. It’s a gas. (Addendum for pedants: it’s a gas at standard temperature and pressure when two atoms of this element bind together with a strong triple bond.) Nitrogen may not have the glamour of a shiny conductive metal, but it brings us life. None of us could exist without this group 15 element inside the proteins, DNA, RNA and energy-carrying adenosine triphosphate (ATP) that make up our cells; that’s why it gets my vote. No nitrogen, no physicists.

Physicists use nitrogen outside their bodies too. It’s a key constituent of caffeine, and in pure liquid form nitrogen brings cooling to 77 K, or 63 K in a vacuum. That’s essential for many applications in cryogenics, superconductivity, space-craft testing, astronomy, blood storage, wart removal, ice cream production and more, as well as science outreach demos involving clouds of Frankenstein-like smoky vapour.

Nitrogen gas isn’t only found in labs and demos – it makes up nearly four-fifths of our atmosphere. Our bodies can’t absorb it from the air, that triple bond is too strong for us. We get our nitrogen from plants, which take it from nitrogen-fixing bacteria in the soil.

We couldn’t fix nitrogen from air ourselves until Fritz Haber and Carl Bosch developed a chemical technique in the early 20th century, destroying the trade in guano – nitrogen-rich bird droppings – in one fell swoop.

The new chemistry was a key factor in the Green Revolution of the 1960s, with chemical fertilizers such as ammonia and nitrates enabling the growth of more food. Polymers containing nitrogen have also enabled modern materials such as Kevlar and superglue.

But nitrogen has a dark side too. If excess nitrates flow from our fertilized fields into rivers and the sea, blooms of toxic plankton flourish. Nitrogen oxides bring us acid rain, destroy the ozone layer, or act as greenhouse gases. And nitrogen is a key component of many explosives; when nitrogen atoms bonded into those compounds reform molecules of nitrogen gas, they free large amounts of energy. This element both brings life and takes it away. But without it there’s nothing.







Source: https://bit.ly/2YlNZev, via Physics World