THERMODYNAMIC PROPERTIES

THERMODYNAMIC PROPERTIES, PROCESS, CYCLE, POINT & PATH FUNCTION

Definition: - Thermodynamic properties are certain characteristics (e.g. vol., pr.) by which its physical condition may be described. 

• It is a point function.

Intensive Properties:

• Independent of mass.
• Value for entire system = Value for individual parts.
• Example: Pressure, Temperature, Density, Viscosity.

Extensive Properties: -

• Dependent of the mass.
• Value for entire system = Sum of the value of individual.
• Example: Volume (Liq.), Energy, Entropy, Enthalpy.

Specific Extensive Properties: -

• Extensive properties per unit mass.
• It is an intensive property (i.e. independent of mass)
• Sp. volume, Sp. Energy.

• PROCESS: - Change of state is known as process.

• TYPES: -

1. Reversible Process: - A process when reversed in direction follows the same path as that of the forward path without leaving any effect on the system and surroundings.

• Reversible Process can be shown on diagram.

Examples: - P-V, T-S, P-T etc. process.

    2. Irreversible Process: - A process when reversed in direction can’t follow the same path as that of the forward path.

• Irreversible Process cannot be shown on diagram.

• All actual processes are irreversible process.

Examples: - Free Expansion process

• PATH OF A PROCESS: - It is the series of state through which a system passes during a process.

• CYCLE: - A system is said to undergone a cycle when the system passes through a series of process and the initial and final points are same.

For a cycle change in property is zero.

If a cycle consists of all the reversible process, then it is a Reversible cycle.

• PATH FUNCTION: -

Exact value of integration can’t obtain.

These functions depend on the path history.

Examples: - Heat, Work.

• POINT FUNCTION: -

Exact value of integration obtains.

These functions do not depend on the path history.

Examples: - Heat, Work.