Why does the bottle of compressed air that I use to clean my keyborad get cold after I use it?

Answer 1

The can gets cold for the same reason that any other refrigeration unit gets cold. (eg air conditioner, refrigerator, dehumidifier). Inside of the can, there is a chemical which can be used as a refrigerant. It's a chemical with a low vapor pressure. When you press the button on top of the can, you open a valve and release some of the pressure from the can. Because this chemical has a high vapor pressure, it evaporates when the pressure drops. The process of evaporation requires intermolecular bonds in the liquid to be broken. In order to break the bonds, energy must be expended. The energy that goes into breaking bonds comes from the ambient thermal energy. As the amount of available thermal energy decreases, the liquid refrigerant becomes cold (its temperature decreases). If you hold the trigger down long enough, the can will become very cold and the evaporation process will slow down and you will notice that the can doesn't work very well anymore as a duster because not much air is coming out. If you add thermal energy to the refrigerant by running hot water over the cold can, you will HEAR and feel the refrigerant boiling inside of the can....the pressure inside of the can increases again to a point where evaporation stops and then you are ready to use your compressed air can again.

http://en.wikipedia.org/wiki/Vapor_pressure
http://en.wikipedia.org/wiki/Aerosol_spray#Propellant

Answer 2

This Site Might Help You.

RE:
Why does the bottle of compressed air that I use to clean my keyborad get cold after I use it?

Answer 3

Why Is Compressed Air Cold

Answer 4

are u sure its just compressed air? if its CO2 or freon, they get very cold when they evaporate. as for air, im not sure, my air tanks and compressor dont seem to get cold as they discharge air, but when compressing any gas it gets hot b cuz its being squished, which scruches the molecules or some thing to that effect. im not a rocket scientist or neurosurgeon, just know a few things. and one thing is that plain old air is 70% nitrogen, 20 something % oxygen, and assorted inert gasses.
hope i helped, but prolly just confused you.
Alan

Answer 5

It's a freezing agent inside with combust air. It is a chemical reaction occuring inside, no need to worry. All natural =D

Answer 6

sorry kevin s- you are totally WRONG- the cause of the reduction in temperature is the expansion of the gas in the can- lower pressure equals a reduction in the molecular motion of the remaining molecules- or, cooling- see the ideal gas law for a further explanation.

Answer 7

It's all about joul Thomson effect... Do search on it
http://en.wikipedia.org/wiki/Joule%E2%80%93Thomson_effect

Answer 8

as you expel the gas, the pressure inside the can gets lower, which means the temperature also gets lower.

Answer 9

For the best answers, search on this site https://shorturl.im/avebJ

IT"S CALLED FROSTBITE !!!!!!!!!

Answer 10

i dont man u should just stick to keyboard dusters to cleanthere safer and funner and safer