Thermodynamic Properties of A System

Thermodynamic Properties of A System 

 Any characteristic of a system is called a property. Every system has certain characteristics by which its physical condition may be described, e.g., volume, temperature, pressure, etc. The list can be extended to include velocity, viscosity, thermal conductivity, modulus of elasticity, coefficient of thermal expansion, resistivity and elevation, etc. The salient features of a thermodynamic property are the following: 

 (a) A property is a measurable characteristic, describing the state of a system. 

 (b) It has a definite value when the system is in a particular state.

(c) It also helps to distinguish one system from another. 

(d) The magnitude of a property depends on the state of the system, and it is independent of the path or route followed by a system during a process. (e) A property is an exact differential.

 Properties may be classified as 

 1. Intrinsic and extrinsic properties according to their origin, and

A} INTRINSIC PROPERTIES :-

These are the basic properties, and cannot be defined in terms of other properties. Their values can be assigned independently for example, length, mass, time, area volume, pressure, temperature, electric current, etc. 

B} EXTRINSIC PROPERTIES :-

These are those properties whose values cannot be assigned independently. These are characteristic of the motion or position of a system and are measured in reference to certain datum such as velocity, acceleration, potential energy, kinetic energy, enthalpy, entropy, etc. 

2. Intensive and extensive properties according to their dependability. 

A} INTENSIVE PROPERTIES :-

These the properties that do not depend on the extent of the system. These properties are independent of the mass also. Properties such as pressure, temperature, density, velocity, etc., are examples of intensive properties. These are properties that vary directly with the extent of the system.

B} EXTENSIVE PROPERTIES :- 

These are properties that vary directly with the extent of the system. These properties depend on the mass of the system. The properties such as mass, area, volume, total energy, etc., are examples of extensive properties.