Understanding Entropy in Thermodynamic Processes
Entropy is a measure of disorder or randomness in a system, and its behavior varies across different thermodynamic processes. Let's explore why entropy does not remain constant in the following processes:
Isothermal Process
- In an isothermal process, the temperature remains constant while heat is transferred into or out of the system.
- As heat is absorbed or released, the entropy of the system changes because entropy is directly related to heat transfer at a given temperature.
- Therefore, in an isothermal process, the entropy does not remain constant.
Isobaric Process
- An isobaric process occurs at a constant pressure. During this process, heat is added or removed, leading to changes in the volume of the system.
- Similar to the isothermal process, the heat transfer affects the entropy, resulting in an increase or decrease in disorder.
- Thus, in an isobaric process, entropy does not remain constant.
Cyclic Process
- A cyclic process involves the system returning to its initial state after a series of changes. Although the overall change in internal energy and enthalpy is zero, the individual steps can involve heat exchange.
- Since entropy can change during each step of the cycle, it does not remain constant throughout the process, even if the net change over one complete cycle is zero.
Adiabatic Process
- In an adiabatic process, there is no heat exchange with the surroundings (Q = 0).
- If the process is reversible, the entropy of the system remains constant, as no energy is added or removed in the form of heat.
- Therefore, in a reversible adiabatic process, entropy does remain constant.
Conclusion
In summary, the processes where entropy does not remain constant are:
- Isothermal Process
- Isobaric Process
- Cyclic Process
In contrast, in an adiabatic process, entropy can remain constant if the process is reversible.