thermodynamics of gases

[denian]

need some explaination of these.

a gas feels cold when it escapes through a small hole of a closed cylinder at high pressure. Explain this phenomenon based on the first law of thermodynamics.
will the escaping gas above be cold if allowed o excape into a vacuum??

[turin]

Probably you will use the ideal gas law as well. Please tell us what you think the first law of thermo is (with definitions/interpretations).