Definitions

Macroscopic approach :-               macroscopic deals with certain quantity of matter  and its behaviour. 

Microscopic approach  :-                microscopic approach concerned with molecular and atomic behaviour of energy and matter.

Thermodynamic system :--Thethermodynamic system is a fixed quantity of matter, around which we can draw a boundary. The boundary may be moveable or fixed. 

There are 3 types of system -- 

1.  Closed system :-                                             In this system there is no interchange of matter between surrounding and system . In this system only energy can cross the boundaries and the boundary also can move or change its position .

2.Open system :-                                                     In this type of thermodynamic system matter and energy both can interchange from the system.

3. Isolated  system :- 

   In this type of thermodynamic system both matter and energy no one can cross the boundaries. Isolated system not influenced by the surrounding .