container
Well, since a gas spreads to encompass its container, it should have the same volume as its container.
It's container
No. A gas always has the volume of the container it's in.
If you are talking about ideal conditions then you can use the ideal gas law: (Pressure)(Volume)=(Number of particles in moles)(R=8.314472 J·K−1·mol−1)(Temperature) or PV=nRT