LPG Cylinder

[AnthreX]

The change in pressure, caused by the release of gas from an Lpg cylinder, will cool the contents.

i am pretty sure that it does cool the contents.

would the water vapour condense on the surface of the bottle and freeze?
if the gas continues to be released.

[HallsofIvy]

Ideal Gas Law: PV= NRT. If Pressure is decreased while Volume remains the same (as in a rigid metal "bottle") Temperature decreases.

"would the water vapour condense on the surface of the bottle and freeze?"

Yes, water vapour in the air outside bottle will form a frost on the bottle. It melts fairly rapidly once you have stopped releasing the gas. When I was young and foolish (I'm not young any more), I worked at a place that dispensed LPG. You had to be very careful not freeze your own hand!

[Adrian Baker]

It is the same with CO2 fire extinguishers - if you hold the cone shaped nozzle when using it, you'll freeze your hand to it!

[AnthreX]

alright thanx for your time and great replies