Nitrogen

both cycles transfer either carbon or nitrogen from the ocean to the atmosphere or from the atmosphere to the ocean.

The conversion of ammonia to nitrate (nitrification) is performed primarily by soil-living bacteria and other nitrifying bacteria. It is important for the ammonia to be converted to nitrates because accumulated nitrites are toxic to plant life. Denitrification is the reduction of nitrates back into the largely inert nitrogen gas (N2), completing the nitrogen cycle.

From the air around us, since air is composed of 78.08% nitrogen. Nitrogen gas is an industrial gas produced by the fractional distillation of liquid air, or by mechanical means using gaseous air (i.e. pressurised reverse osmosis membrane or Pressure swing adsorption). Commercial nitrogen is often a byproduct of air-processing for industrial concentration of oxygen for steelmaking and other purposes.

No. Plants cannot use elemental nitrogen. The nitrogen must first be fixed, either by lightning or by nitrogen-fixing bacteria. Some plants have such bacteria in their roots.

water

What factors might lead to a positive nitrogen balance?

Firstly, N2 is treated sometimes as an inert gas as it is used to create an inert atmosphere so that no reactions take place. But nitrogen has many compounds as it is more chemically reactive than helium or any other inert gases. Its compounds: e.g. Ammonia, Nitric Acid etc. More on: http://en.wikipedia.org/wiki/Nitrogen

Lithium is altogether a bigger element than hydrogen. Hydrogen is the smallest element, and lithium is listed later on the periodic table, so lithium's radius is just plain bigger than hydrogen.

Antoine Coefficients for Nitric acid are

A=6.6368

B=1.406

C= -52.15

range 274/376 (K)

reference :- Vapour Pressure and Antoine Constants for Nitrogen Containing compounds

It gains three, loses five, or shares pairs of electrons

This temperature is - 210 0C.

It goes back into the soil.

Because the nitrogen in the air is in a form not usable to animals and plants. The only way animals get nitrogen to build protein and nucleic acid is by eating it. This is usually through plants, which get there nitrogen from the soil. They get it from the soil because bacteria in the soil turn the atmospheric nitrogen into a usable form.

In a water ecosystem cyanobacteria (a.k.a. blue-green algae) transform the nitrogen from the atmosphere into usable forms of nitrate

When the animals breathe in nitrogen it goes into their bodies so when they die and decompose the nitrogen they breathed in is now in the soil and also when they fertilize on the land.

Nitrogen compounds known as Nitrates found in the soil

N2

plants take in nitrogen compounds through their roots.

Nitrogen is the most abundant element in the Earth's atmosphere. Bacteria in the soil 'fix' the nitrogen gas into compounds which can be taken in by plants; the plants get eaten by animals & they use the nitrogen to make proteins.

wcovalency means the max number of electron an atom can share with others.

nitrogen can share 5 but due to the absence of d orbital it can only share 4.

therefore the actual covalency in 4.

Hydrogen and Oxygen are essential for life because of the tasks they preform. Hydrogen, which is taken in through H2O as well as H2, is used for the transfer of energy for many vital systems. Oxygen is used for much of the same thing; transferring sugars to muscle fibers and vital organs.

Yes

dry ice −56.4 °C and liquid nitrogen is −196 °C

N=3

I=2.6

You do the math.

3<2.6x3