Give reasons
(a) A gas fills completely the vessel in which it is kept.
Answer
The particles of gas have negligible force of attraction between them , hence the particles are very loosely bound.
Hence, a gas fills completely the vessel in which it is kept.
The particles of gas are loosely bound so fill the entire vessel.
First and second vessel have the same number of particles, but depending on the space available, the particles space out due to negligible force of attraction