Thermodynamics - system - surrounding - boundary - types of system - examples - state function - path function

1. Dr.P.GOVINDARAJ
Associate Professor & Head , Department of Chemistry
SAIVA BHANU KSHATRIYA COLLEGE
ARUPPUKOTTAI - 626101
Virudhunagar District, Tamil Nadu, India
THERMODYNAMICS

2. THERMODYNAMICS
• It is the branch of physical chemistry that deals about the change of heat energy
in chemical and physical process
Importance of thermodynamics :
• Equations relating to certain physical properties with the variation of temperature
and pressure have been developed with the help of thermodynamics law
• The laws of thermodynamics can be used to predict the direction in which a
process would proceed

3. THERMODYNAMICS
The three importance terms used in thermodynamics are
a) system
b) surrounding
c) boundary
Terminology of thermodynamics :

4. • A part of universe under our observation is called as system
System
THERMODYNAMICS
• The remaining part of the system in the universe is called as
surrounding
Surrounding
• The space separating the system from its surrounding is called
as boundary
Boundary

5. • System which can exchange both energy and matter with its surrounding is called
as open system
Types of System
THERMODYNAMICS
Open system
Example: Heating water and cooling hot water in a glass beaker

6. • System which can exchange energy but not matter with its surrounding is called
as closed system
Closed system
Example: Heating water and cooling hot water in a closed glass vessel
THERMODYNAMICS

7. • System which can neither exchange energy nor matter with its surroundings is called
as isolated system
Isolated system
Example: Thermally insulated scaled tube containing liquid and vapour
THERMODYNAMICS

8. • System which contains large number of particles (molecules, atoms, ions etc..) is
called as macroscopic system
Macroscopic system
THERMODYNAMICS
• System in which matter can exist in single phase is called as homogeneous system
Homogeneous system

9. THERMODYNAMICS
• System in which matter can exist more than one phase is called as heterogeneous system
Heterogeneous system
Macroscopic properties
• The properties associated with macroscopic system are called as macroscopic properties
Example : Pressure, Volume, Temperature etc.,,

10. THERMODYNAMICS
• State of a system is one which can be defined by telling the macroscopic properties
of the system
i.e., the state of a system is fixed by its macroscopic properties
State of a system
• When there is a change in macroscopic properties the system can change from
one state to another
P1, V1 & T1 P2, V2 & T2

11. THERMODYNAMICS
• The macroscopic properties which depends on the state of the system and varied
on changing the system from one state to another state are called state function
Example, Pressure, volume, temperature, internal energy (E), enthalpy (H),
free energy (G), etc., are some of the thermodynamic properties of the system
that are state functions
State function
P1, V1 , T1 & E1
P2, V2 , T2 & E2

12. THERMODYNAMICS
• The path function are the macroscopic properties which depends upon the path by
which the system can change from one state to another
For example, work (w) and heat (q) are some of the thermodynamic properties
of the system that are path functions
Path function
A B
V
W1
W2

13. THERMODYNAMICS
• The properties that depends on the amount of matter present in the system are
called extensive properties.
Example: Volume, number of moles, mass, energy, internal energy, entropy etc.
Extensive properties
• The properties that are independent of the amount of matter present in the system
are called intensive properties.
Example: boiling point, melting point, density, refractive index, surface tension etc.
Intensive properties

14. THERMODYNAMICS
Zeroth law of thermodynamics
• When two objects are in thermal equilibrium with the third object, then there is
thermal equilibrium between the two objects itself

15. THANK YOU