Free Expansion

[Maria George 3K]

What is free expansion? what conditions does it have?
Could it be reversible or irreversible, or is it just one of these?

[Upaush Sharma]

Free expansion is an irreversible process where a gas expands into a vacuum or larger volume without there being any external force being applied to it. This means that the gas does not do work so the internal energy of the system remains the same.

[005925345]

Free expansion is always an irreversible process where there is no heat transfer or work done. In free expansion, there is no change in the internal energy of the system, which naturally follows from there being no heat or work.

I'm not entirely sure about the specifics of this happening, but a quick search helped me find that one possible condition would be that a piston containing a system of gas would have to be moving away (decompressing) faster than how fast the molecules of gas are moving.