Concept in thermodynamics

System:
        The system may be defined as any specific portion of universe which is chosen to study the thermodynamics’ properties.
Example:
  1) Open vessel containing boiling water
  2) Wooden box which is used in physical experiment

Surroundings:
        All other part of universe other than system where observation is made known as surrounding.

Boundary:
        The real and imaginary out line which separates the system from surrounding is known as boundary.

Types of system:-
1) Open system
2) Closed system
3) Isolated system 

1)Open system :-
                     The system in which exchange both matter as well as energy with its surrounding is known as open system.
   
Example:-
1)    Open vessel’s containing water.
2)    Cup of tea 

2) Closed system:-                       

               The system which can exchange only energy but not matter with its surrounding is known as closed system.  Here the energy is either gained or loss by the system with surrounding but does not exchange matter.

            Example: - closed vessel containing boiling water 

3) Isolated system:-

                        The system cannot exchange either matter or energy (heat) with its surrounding is called isolated system. 

Example: - Hot water in thermos

Property of system:-    

 Property of system are generally classified into two type

1)     Extensive property

2)     Intensive property 

Extensive property:-

                   The property of system whose magnitude depends upon the quantity of matter present in the system is known as extensive property.

Example: -

1)       Mass   2) Volume 3) Energy. 4) Heat capacities 5) Number of moles

Intensive property:-

             The property of system whose magnitude is independent of the quantity of matter present in the system is known as Intensive property.

Example:-

1)     Temperature.    2) Density   3) Melting point 4) Viscosity 5) Refractive index 

6) Melting point

 State variable;

                         Every system has a certain measurable thermodynamics properties such as temp. Pressure and volume this property are state variable.

State of system: -

           State of system is defined by specifying the values of state variable like temp. Pressure, volume etc

                   If any one of these property changed then there will be change in a state of system.