Cold Liquids

[adsl1981]

Hello

 

Everyone i am interested to know if any of you know of such a liquid that by any chance is very cold stay cold: D

 

 

Thanks a lot

[aj47]

Liquid nitrogen is pretty damn cold as is most liquid gases e.g. hydrogen, not sure if thats what you mean though.

[RyanJ]

Hello

 

Everyone i am interested to know if any of you know of such a liquid that by any chance is very cold stay cold: D

 

 

Thanks a lot

 

What you said there makes no sence at all, can you restate the question by any chance?

 

As aj47 said any liquid gas is really, really cold.

On an interesting note, Helium is the only known substance that does not form a solid at standard preassure.

 

Cheers.

 

Ryan Jones

[woelen]

Hello

 

Everyone i am interested to know if any of you know of such a liquid that by any chance is very cold stay cold: D

 

 

Thanks a lot

You mean that you want to know a cold liquid, that remains cold? If that is what you mean, then I have to disappoint you. Such a liquid does not exist. Any cold object, exposed to room temperature, will finally reach that temperature. With good isolation you can make that process slow, but you cannot stop that. E.g. liquid nitrogen either becomes warmer (and then pressure builds up), or it evaporates and when all has evaporated, no liquid is left anymore.

[adsl1981]

Yes that was what i meant thank a lot for the help i was pretty sure i would never find anything.

 

 

Thanks guys

[shigmeister]

You know you said there was no such liquid. Well I was looking at a deodorant can and when you spray it it's cold !. Does this mean the liquid they use is always cold ! ?

 

 

Thanks.

[RyanJ]

You know you said there was no such liquid. Well I was looking at a deodorant can and when you spray it it's cold !. Does this mean the liquid they use is always cold ! ?

 

 

Thanks.

 

No, its because of the preassure differences. If you have a bottle of somehting like compressed butane from the portable burners then shake at back and forth it will get VERY cold but as soon as you stop it returns to normal temperature

 

Like I said its to do with preassure differences though i am not 100% shure as to why

 

Cheers,

 

Ryan Jones

[jdurg]

It has to do with PV=nRT. The Volume goes up pretty much infinitely when you let the gas escape from the can and the pressure only drops to normal atmospheric pressure. Since R is constant and the number of moles (n) is constant, the temperature has to decrease.

[RyanJ]

It has to do with PV=nRT. The Volume goes up pretty much infinitely when you let the gas escape from the can and the pressure only drops to normal atmospheric pressure. Since R is constant and the number of moles (n) is constant, the temperature has to decrease.

 

Ah, I see - thanks for the explination (Makes more sence now )

 

Cheers,

 

Ryan Jones

[akcapr]

temperature and pressure are directly related

[raivo]

You know you said there was no such liquid. Well I was looking at a deodorant can and when you spray it it's cold !. Does this mean the liquid they use is always cold ! ?

 

No it does not mean exactly that. Liquid in deodorant bottle is at great pressure. If it gets out it starts to evaporate. Any part that evaporates takes a lot of heat with it, so liquid that remains ( for example on your body ) goes colder and colder as long as it is not yet completely evaporated. Fridges use this to make cold but there all the process goes in the copper tubes.

 

In the same reason acetone or gasoline go rather cold if vessel is left open and even water that stands in open beaker at your desk is always some degrees colder than air around it. In respect of this "colder" liquids are those that evaporate fastest but only if they can freely evaporate.

[akcapr]

does liquifying a gas via pressure, not cold, cause it to go cold just because it turns liquid? not counting evaporation

[Cap'n Refsmmat]

No. Adding pressure makes it warmer. You have to add pressure and dissapate heat at the same time.

[RyanJ]

No. Adding pressure makes it warmer. You have to add pressure and dissapate heat at the same time.

 

If that is the case, how do you explain the gas in gas canisters being cold? They are stored under pressure and they do get very cold by your reasoning that is impossible... Unless they conduct the heat away very effectlvley to get cold so fast.

 

Cheers,

 

Ryan Jones

[woelen]

The cold you feel only occurs when some gas is allowed to escape from the canister. Evaporation of a gas (liquid --> gas) costs quite a lot of energy and that causes the cold feeling.

 

When the gas is not liquid, but merely under high pressure, then the expansion, due to the release of the gas, also costs energy. That also makes the canister feel cold.

 

If you have canister with a liquid gas or a high-pressure gas and you do not do anything with it, then it does not feel cold.

 

A nice observation is when you take a bottle of beer and you remove the cap. Then at once the pressurized carbon dioxide expands and it cools down considerably. You see a little cloud, due to expansion (and consequent cooling down) and condensation of water droplets in the cold gas.

[jdurg]

Liquified air, and gases in general, are typically made by compressing and decomporessing the gas/air in succession until it liquifies. I believe this works because the increase in temperature experienced when compressing the gas is a bit less than the decrease in temperature you get when you decompress a gas, so if enough cycles are done the gas liquifies.

[akcapr]

The cold you feel only occurs when some gas is allowed to escape from the canister. Evaporation of a gas (liquid --> gas) costs quite a lot of energy and that causes the cold feeling.

 

When the gas is not liquid' date=' but merely under high pressure, then the expansion, due to the release of the gas, also costs energy. That also makes the canister feel cold.

 

[/quote']

 

ya thats what i was thinking.

[chemfreak]

You mean that you want to know a cold liquid, that remains cold? If that is what you mean, then I have to disappoint you. Such a liquid does not exist. Any cold object, exposed to room temperature, will finally reach that temperature. With good isolation you can make that process slow, but you cannot stop that. E.g. liquid nitrogen either becomes warmer (and then pressure builds up), or it evaporates and when all has evaporated, no liquid is left anymore.

ya its called, get ready for a fancy word now, equilibrium, i think:D

[chemfreak]

Ah' date=' I see - thanks for the explination (Makes more sence now )

 

Cheers,

 

Ryan Jones[/quote']

what the heck i thought i had brains until now, but hay im 11. I dont even take pre algebra

[chemfreak]

No it does not mean exactly that. Liquid in deodorant bottle is at great pressure. If it gets out it starts to evaporate. Any part that evaporates takes a lot of heat with it' date=' so liquid that remains ( for example on your body ) goes colder and colder as long as it is not yet completely evaporated. Fridges use this to make cold but there all the process goes in the copper tubes.

 

In the same reason acetone or gasoline go rather cold if vessel is left open and even water that stands in open beaker at your desk is always some degrees colder than air around it. In respect of this "colder" liquids are those that evaporate fastest but only if they can freely evaporate.[/quote']

 

 

(in stupid voice)cold is only the absence of heat:D

[Daecon]

What about Water or CO₂ in a fire extinguisher?

 

I'm pretty sure that's very cold when you first start spraying it, even though the cannister is most likely at room temperature.

[jdurg]

Water is not used in a fire extingusiher, and when CO2 is used it is used under a great deal of pressure. Read through the thread and you'll see that the decompression of a compressed gas results in a significant drop in temperature.