Hello there in this post we study Thermodynamic properties, Thermodynamic process, and Thermodynamic cycles.
Thermodynamics properties
Every Thermodynamic system has some certain characteristics by which its physical condition may be described. Hence Thermodynamic property is the characteristics of a system that can be used to describe its state and predict how it will respond to changes in its environment.
Also these thermodynamic properties are macroscopic in nature.
If all the properties of the system have definite values then this system is called definite system.
In other words properties are the coordinates to describe the state of the system.
An operation in which one or more properties of the system changes is called change of state.
Thermodynamic properties are divided into two main categories:
- intensive properties and
- extensive properties.
Extensive Properties:
Extensive properties depend on mass.In simple terms,These properties depend on the size or amount of the substance in the system. Doubling the size or amount will double the extensive property.
If the mass is doubled, then extensive property is also doubled.
Example : mass, Volume,Internal energy,entropy enthalpy.
Intensive Property:
These are independent of the size or amount of the substance in the system.Hence they do not depend on the mass of the system.
Examples: Temperature, pressure, density and specific heat capacity.
Intensive Property vs Extensive Property: Key Difference between them
Why density is an intensive property?
Density is considered an intensive property because it does not depend on the size or the amount of substance in the system. Density is defined as the ratio of mass to volume:
Density= mass / Volume.
Both mass and volume are extensive properties, meaning they scale with the amount of material. However, when you divide mass by volume, the scaling cancels out, and the result—density—remains constant regardless of the system’s size.For example, if you take a sample of a material and divide it into two equal parts, each part will have half the mass and half the volume, but the ratio of mass to volume (i.e., the density) remains the same. Therefore, density is independent of the total amount of substance, making it an intensive property.
Thermodynamic Process
A thermodynamic process refers to the series of steps or changes that a system undergoes, often involving heat (thermal energy), work, and internal energy. These processes are described using the laws of thermodynamics.
There are four key types of thermodynamic processes:
- Isothermal process.
- Adiabatic process.
- Isobaric process.
- Isochoric process.
Read more about thermodynamic process.
Thermodynamic cycle:
A thermodynamic cycle is a series of thermodynamic process in which final state is identical with the initial state.
During this thermodynamic cycle the system undergoes different processes (like isothermal, adiabatic, isobaric, or isochoric) and, after completing the sequence of processes, returns to its original initial conditions.
The key feature of a thermodynamic cycle is that it can be repeated indefinitely, making it the basis for engines, refrigerators, and other energy conversion devices.
In a thermodynamic cycle:
- Work is done on or by the system during each process.
- Heat is either absorbed or released.
- The system returns to its original state, meaning that the internal energy change over a complete cycle is zero (ΔU = 0, according to the first law of thermodynamics).
Types of Thermodynamic cycles:
- Carnot cycle.
- Otto Cycle.
- Diesel cycle.
- Rankine cycle.
- Brayton cycle.
- Refrigeration and heat pump cycle(Reversed carnot cycle).