2006-10-21 22:23:35 · 6 answers · asked by amir_elmaani 1 in Science & Mathematics ➔ Chemistry
In a sealed container you minimize the escape of the vapor.
To really minimize losing the liquid you will need to use a thermus, which by the way is the way you get liquid nitrogen for you scientific use.
I have used it to preserve samples and I had opened and closed many times. Sealing is not the problem, you need a thermus or dewar to really keep it going.
2006-10-22 00:56:21 · answer #1 · answered by Dr. J. 6 · 0⤊ 0⤋
It doesn't. It stays liquid only as long as the TEMPERATURE remains below the critical point of nitrogen. At room temperature it will be a gas and at considerable pressure! From a Health and Safety point of view it wouldn't be a good idea to seal liquid nitrogen in any container.
2006-10-22 08:05:31 · answer #2 · answered by Anonymous · 0⤊ 0⤋
Because it is placed inside a dewar flask, or similar insulating container. Like a thermos bottle, it reduces the heat transfer and the associated heating of the liquid - although eventually it will evaporate, and would need to be replenished. This is why these tanks contain some kind of a vent to prevent over-pressurizing the container. Industrial plants sometimes use liquid N2 for freeze seals to isolate mechanical systems. When they do, they use a lot of it.
2006-10-22 05:31:40 · answer #3 · answered by loveourcountry 2 · 0⤊ 0⤋
Because those containers are well insulated, and not perfectly sealed. If they were sealed, they would explode. The nitrogen does evaporate, but the insulation helps maintain a lower temperature and reduce loss. They need to be topped up occasionally.
2006-10-22 05:34:27 · answer #4 · answered by Labsci 7 · 0⤊ 0⤋
When it is sealed, it is compressed and has no space to evaporate back into a gas.
2006-10-22 05:32:26 · answer #5 · answered by sverthfreyr 3 · 0⤊ 0⤋
Because it can't evaporate, or "boil" away.
2006-10-22 05:28:20 · answer #6 · answered by Scabius Fretful 5 · 0⤊ 0⤋