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Hello, Science Line,
Although Nitrogen can combine with chemicals to produce unpleasant byproducts as a result of fuel combustion (nitrogen oxides in smog, etc.), I was wondering if atmospheric nitrogen can actually be harnessed (somewhat like atmospheric oxygen) to produce power in any way? Although nitrogen has a strong tendency for inertness, since it makes up the bulk of air, it is a shame that it cannot be harnessed somehow -- are there any oxidizers/fuels which can be made to react energetically/explosively with nitrogen gas, especially under heat and/or pressure? Thank you very much.
Question Date: 2014-12-15
Answer 1:

Because Nitrogen is very stable, it takes a lot of energy to turn it into anything other than pure nitrogen (N2). Combustion in cars gives it enough energy to for NOx gases, but in general, there isn't much energy to harness in nitrogen gas. For chemical reactions to occur, it must result in something more stable than the reactants going into it. Because very few things are more stable than N2, it doesn't make much sense to try to use it this way. This is a really good thought though, and one that has actually been investigated thoroughly for about a hundred years! Many other products (such as explosives or fertilizer) require nitrogen, and there is so much in the air it makes a good source.

To get the nitrogen from the air, a fairly expensive method called the Haber process is used. It was developed only about 100 years ago and is responsible for the massive increase in world population due to the increase in fertilizer. It requires high temperatures and a good catalyst, but despite the cost is one of the most common chemical productions in the world. If you're interested in this kind of thing, you may want to look into Chemical Engineering.


Answer 2:

Although we don't use atmospheric nitrogen to produce power, atmospheric nitrogen is used to produce fertilizer that is needed to grow most of the food we consume. Some estimates are that a third of the world's population is sustained by fertilizer produced in this way. To produce ammonia that is eventually incorporated into fertilizer, H2 is mixed with N2 at high temperatures (300 - 500 Celcius) and pressures (~200 atmospheres) in the Haber process.


Answer 3:

I'm not aware of any ways in which nitrogen gas can be used directly to make fuel or electricity the way that, for example, hydrogen can be used. However, nitrogen is a very abundant and useful element that is in a variety of compounds and materials, some of which are relevant to the energy sector.

I can tell you one example that I work with: nitrogen and gallium can be chemically combined to produce a material called gallium nitride (GaN). GaN is a semiconductor that emits light when powered with electricity, and it is the material used in energy efficient LED lights. An LED bulb consumes just a 10th of the power of a traditional incandescent bulb with the same brightness.

This material and application have had such a great impact in reducing electricity consumption that the most recent Nobel Prize in Physics was awarded for the invention of the energy efficient LED.


Answer 4:

The answer is probably not, and it has a lot to do with bond energies. A really basic way to estimate if a chemical reaction will release energy is to compare the chemical bonds you make to the chemical bonds you must break as the result of the reaction. If you have to break stronger bonds then you end up making, the reaction is much less likely to happen, and will consume as opposed to release energy. Atmospheric nitrogen is found in the form of N2, and it forms a triple bond, which means that each atom contributes 3 electrons to the bond as opposed to 1 each for a single bond. This bond is extremely strong, and you can find some tables of bond energies to examine for yourself exactly how strong it is. A table I found with some quick googling says that the nitrogen tripple bond is around twice as strong as the bond that holds the oxygens together in O2. This means that if you were to break apart a N2 molecule, it would be hard to find a bond to place it in that would have a lower energy.



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