A collection of an extremely large number of atoms or molecules confined with in certain boundaries such that it has a certain value of pressure, volume and temperature is called a thermodynamic system.Anything outside the thermodynamic system to which energy or matter is exchanged is called its surroundings.
Thermodynamic system may be of three types :
(i) Open system : It exchange both energy and matter with the surrounding.
(ii) Closed system : It exchange only energy (not matter) with the surroundings.
(iii) Isolated system : It exchange neither energy nor matter with the surrounding.
