In the physical definition of any matter, most of the physical properties are subdivided into intensive and extensive properties. The identity and function of any substance or system are defined by these properties. Let us have a look at these two sub-categories in detail.
Intensive properties of any matter are those physical properties that are independent of the mass of the substance or the system. Intensive properties are also known as bulk properties. Most intensive properties are used to define the identity of that substance or system.
Pressure (P), temperature (T), color are all intensive properties. Other examples include density, melting point, boiling point, etc. All these parameters do not change with the mass of the body. For example, the melting point of 1 kg ice and 1 gm of ice is the same= 0ᴼC.
Chemical potential, refractive index, specific heat capacity, thermal conductivity, viscosity are all examples of intensive properties.
Extensive properties of any matter are those physical properties that depend on the mass of that matter. These properties are proportional to the size or mass of the system.
The weight of the system increases with the mass. Similarly, the volume also increases with the mass of the substances. The heat capacity is directly proportional to the mass of a system. The energy stored in a system is dependent on the mass of the system. For example, two boxes of the same material but the different weights will also differ in their properties.
Some other examples of extensive properties are enthalpy, entropy, Gibb’s energy, internal energy, etc.
It is easy to distinguish between intensive and extensive properties. One needs to double the mass of the system. The physical properties that change with an increase in mass are extensive properties. However, those physical properties that do not change with an increase in mass are intensive properties.
Both the intensive and extensive properties are useful in understanding the thermodynamics of a system. Thermodynamics is the study of the flow and transformation of heat forms of any matter. It depends on the matter and the factors determining its state. Parameters that define the thermodynamic properties are:
Path function- the parameter defined by the path taken by the matter or the system to reach the current state. Work done due to frictional force is an example of path function.
State functions, also known as state variables, are defined by the current state, and not the path that is taken to reach that state. Temperature is an example of state function.
The state function of the system depends on the initial and final position of the system. However, the path functions of the system depend on the path taken by the system to reach from the initial to the final state. Both the state and path functions are important parameters to study the thermodynamic properties of a system.
1. What are Intensive Properties?
Properties that do not depend on the mass are intensive properties.
2. Give Examples of Intensive Properties.
Temperature, pressure, density, conductance, refractive index, etc. are all examples of intensive properties.
3. What are Extensive Properties?
Properties that depend on the mass are extensive properties.
4. Give Examples of Extensive Properties.
Mass, volume, heat capacity, internal energy, etc. are examples of physical properties.
5. How can One Distinguish Between Intensive and Extensive Properties?
To distinguish between the intensive and extensive properties of a system, one needs to increase the amount of that system. If the property changes with the mass of the system, it is an extensive property. If the property does not change with the mass of the system, it is an intensive property.