Gases have 4 major characteristic properties :
-Compressibility : it can be easily compressed so its volume will be reduced
-Expansibility : when there is pressure on gas , it collapses . and when pressure goes away , it regains its original volume again
-Diffusibility : the gas atoms fly in the intermolecular spaces of the opposite gas component when mixed together
- Exertion of pressure : when it undergoes pressure , its particles move in all directions