Thermodynamic Processes: Adiabatic/Isochoric/Isobaric/Isothermal

In summary, the adiabatic process is a hypothetical system that does not exist in reality. It is my understanding that this system is not possible to exist, as there is no insulator on Earth that can hold the temperature at the same level as the environment. If you add energy to the system, you must alleviate the pressure in order to maintain the adiabatic system. The isochoric process is a process where the volume does not change, while the isobaric process is a process where pressure remains constant. Finally, the isothermal process is a process where temperature does not change.
  • #1
avocadogirl
53
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Adiabatic process: a process where no heat is gained or lost. it is my understanding, however, that this is a hypothetical system. There is no insulator on Earth good enough to allow this system to exist, except to approximations.

So, what happens is you have a system where whatever is inside the system is held at the same temperature as the surrounding environment? Is that considered adiabatic?
Now, what if you add energy to the system, how do you maintain an adiabatic system? Do you alleviate the pressure?

Isochoric process: a process where the volume doesn't change. no work can be done on an isochoric system because the volume is not allowed to change.

Is this why the thermodynamic equation describing change in energy cannot be based solely upon work but, rather, it has to include a term for heat transfer?

Isobaric process: a process where pressure remains constant.

In reality, is this system only possible if you adjust temperature and volume in equal proportion, so as to avoid increases or decreases in pressure? Is there another scenario where an isobaric process is possible?

Isothermal process: a process where temperature does not change.

Does an isothermal system have to be adiabatic? Or does heat flux make the system not adiabatic? In what system do you add energy and keep temperature the same?

Thank you.
 
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  • #2


My you have swallowed the thermodynamic dictionary.

:smile:

For any system a state is a condition where the values of certain variables are known (definable).

We find that we only need a few variables to totally define the state of a system. These are connected by an equation of state such as PV/T = a constant.
Clearly we only need to know two of these to define the state of a system, as we can calculate the third from this equation.

Now other equations including other properties are also possible and the first law is about the energy transferred to a system or withdrawn from it.

So if we have a system at one state (P1 , V1, T1) and we move it to a second state, (P2 , V2, T2) we can achieve this by doing mechanical work on it and/or adding heat energy.

Adiabatic changes occur when the heat added is zero.
A good example of an adiabatic change in real life is a sound pressure wave. It is adiabatic because it is so quick thermal energy does not have a chance to transfer.
 
  • #3


Very interesting. Thank you, very much, for your reply.
 
  • #4


avocadogirl said:
Adiabatic process: a process where no heat is gained or lost. it is my understanding, however, that this is a hypothetical system. There is no insulator on Earth good enough to allow this system to exist, except to approximations.

So what! There is no such thing on Earth as an exact right triangle, or an exact equilateral triangle, or any other exact geometric shape. These are all idealizations. This does not prevent you from usefully employing Euclidean geometry to solve practical problems, does it?
 
  • #5


I would like to clarify and expand upon the information provided about these thermodynamic processes. Adiabatic, isochoric, isobaric, and isothermal processes are all fundamental concepts in thermodynamics that describe the behavior of a system as it undergoes changes in temperature, pressure, and volume. These processes can occur in both ideal and real systems, but the ideal conditions are often used as simplified models for understanding the behavior of real systems.

An adiabatic process is one in which no heat is gained or lost from the system. This means that the system is thermally isolated and does not exchange heat with its surroundings. In reality, it is difficult to achieve a truly adiabatic system, as there will always be some transfer of heat due to imperfect insulation. However, in certain cases, such as in a well-insulated container, the heat transfer may be negligible enough to approximate an adiabatic process.

An isochoric process is one in which the volume of the system remains constant. This means that no work can be done on the system, as work involves a change in volume. An example of an isochoric process is heating a sealed container of gas, where the volume of the container remains constant but the pressure and temperature of the gas increase.

An isobaric process is one in which the pressure of the system remains constant. This can occur in a variety of systems, such as a gas in a piston-cylinder apparatus where the piston is free to move and maintain a constant pressure. In reality, isobaric processes are often achieved by adjusting temperature and volume in equal proportion, as mentioned in the content. However, there are other scenarios where an isobaric process is possible, such as heating a liquid in a container that can expand without changing the pressure.

An isothermal process is one in which the temperature of the system remains constant. This can occur in a variety of systems, such as a gas in a piston-cylinder apparatus that is in thermal contact with a heat reservoir. In this case, the heat transfer from the reservoir maintains a constant temperature in the gas. An isothermal system does not necessarily have to be adiabatic, as heat flux can still occur in an isothermal process.

In summary, these thermodynamic processes are important concepts in understanding the behavior of systems undergoing changes in temperature, pressure, and volume. While ideal conditions may be used to simplify these processes, they can also
 

1. What is a thermodynamic process?

A thermodynamic process is a physical transformation of a thermodynamic system from one state to another. It involves changes in temperature, pressure, and volume of the system.

2. What is an adiabatic process?

An adiabatic process is a thermodynamic process in which no heat is exchanged between the system and its surroundings. This means that the system is thermally insulated and does not gain or lose heat during the process.

3. What is an isochoric process?

An isochoric process is a thermodynamic process that occurs at constant volume. This means that the system does not change in volume during the process, but can experience changes in temperature and pressure.

4. What is an isobaric process?

An isobaric process is a thermodynamic process that occurs at constant pressure. This means that the system maintains a constant pressure during the process, but can experience changes in temperature and volume.

5. What is an isothermal process?

An isothermal process is a thermodynamic process that occurs at constant temperature. This means that the system maintains a constant temperature during the process, but can experience changes in pressure and volume.

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