why cant you keep nitrogen as liquid that much time?

Question

it evaporates less than a week

Answer 1

Hello,

My name is Arya Bhatta.Here is the explantion for ur question.This will be critical to understand.If U understand ,this concept help U to explain many thermodynamical properties like expansion of matters,anolomous behaviour of water and some special properties of Uranium Fission.
I hope that this explanaiton will satisfies U 100 %.

Explanaiton : Basically the nitrogen atom is large in the aspects of the compressing the gas into liquid.As the nitrogen compressed into liquid ,the nitrogen atoms gets closer.Because of large number of electrons in the outer most shell there will be tremendous feild of repulsions from each other.Put this concept in ur mind.


The next thing happens is, consider three atoms are arranged side by side.The middle atom of the three atoms will repels with the first atom, and then moves towards the third atom and again moves toward the first atom.This procees occurs throught the liquid and then at some point of time the entire liquid system will attain the near SHM(Simple Harmonic motion).Now conside this equations ,from the laws of SHM.

U = U0{[R0/r]12 - 2 [R0/r]6}

Here U is the inter-energy of the system.

'r' is amplitude of the SHM
R0 exceeds froms +r to -r
U0 is positive constant which will be in the units of the Joules.

From this energy equation,the equation of internal forces of nitrogen is obtained by differtiating with respect to distance between the two atoms.

dU/dr = Fr = 12U0/R0{[R0/r]13
-[R0/r13]

If the force is positive r < R0
if the force is negitive vice-versa.So in the case of Ntrogen the force will be extremely positive.The loose its SHM state.Hence the internal energy does not remain constant.There the nitrogen in liquid state is always unstable.In the case of gaseous state of nitrogen,the atoms are at a distance such that r ~R 0.

Then the the motion will be under nearly SHM.So energy is nearly constant.Therefore the gas will be in the stable state
urs respectfully,

-Arya Bhatta.

Answer 2

Where will you store it? At some time or the other, the outside heat will get to it causing it to evaporate. If it can be kept at a high enough pressure and low enough temperature, the nitrogen would remain a liquid. Temperatures of -196 degrees are obtained by the 'Joule-Thomson' effect and not by keeping it at that temperature. In that, nitrogen in its gaseous state at very high pressure is passed through a hole, causing its temperature to fall. Otherwise, such temperatures are impossible to attain continuously till now.

Answer 3

Nitrogen is not actually a liquid. In it's natural form it is a gas.

It is also not actually evaporating. At above -200C it begins to boil. As it boils (vaporizes) it expands several hundred times and turns to gas.

If it is kept under insulated pressure and not allowed to expand, it does not require cooling and it will remain in it's liquid state.

LN2 tanks are pressure tanks with a vacuum seal fully encapsulating this pressure tank with the liquid inside of it, with an external insulated vessel insulating this vacuum wall. This allows for a superior insulation which allows the nitrogen to remain in it's liquid form without an external cooling method.

Answer 4

You can use refrigeration machinery to cool it, but that takes energy, and a regular home freezer would not work because it isn't nearly cold enough. There is no "free" way to keep it. Even the best insulated container allows some heat to leak through, and when it does, the liquid nitrogen will slowly boil away.

Answer 5

Because it has a boiling point of -196C and it's hard to keep it below this temperature. The vessels it is typically stored in are not perfect and do leak heat to the LN2 thus causing it to boil into a gas.

Answer 6

its has to be constantly cooled to about -80*C and kept under pressure to be liquid.

on uranus and saturn its actually uite easy to keep liquid nitrogin.