Why does temperature fall in endothermic process in adiabatic system?

[zenterix]

TL;DR

I read in a thermodynamics book that "an endothermic process is a process in which energy is acquired from its surroundings as heat" and "when an endothermic process occurs in an adiabatic system, the temperature falls".

In addition, "not all boundaries permit the transfer of energy even though there is a temperature difference between the system and its surroundings. Boundaries that do permit the transfer of energy as heat are called diathermal; those that do not are called adiabatic."

If we have an endothermic process in an adiabatic system, the process is acquiring energy from its surroundings; yet, the adiabatic system has a boundary that does not permit transfer of energy. So how can the temperature fall?

I asked chatgpt and part of the answer was the following:

In an endothermic process, the system absorbs heat energy from its surroundings. However, since the adiabatic container does not allow heat exchange with the surroundings, the heat that is absorbed by the system stays within the system. As a result, the internal energy of the system increases because it has gained energy through the endothermic process.

Now this also doesn't make any sense to me.

The system absorbs heat energy from surroundings, but the adiabatic container does not allow this heat exchange, so the heat that is absorbed (from where???) by the system stays within the system.

 

[Borek]

Congratulations, you have just learned ChatGPT is not reliable. Simply don't ask it such questions and don't use it as a part of the learning process.

I feel like the problem boils down to lousy use of the word "surroundings".

During the endothermic adiabatic process energy is consumed by the system, but the only source of the energy is the system itself, not its "surroundings" (from which it is isolated). So if the energy is used, it is the internal energy of the system itself, and the temperature of the system goes down, in a way it "eats" itself.

However, assuming the system consist of many molecules, if you look at a single molecule within the system, it absorbs the heat for its own surroundings - that is, from other molecules within the system.

 

[chemisttree]

…or the endothermic process in an adiabatic system converts kinetic energy of the particles (molecules?) into some sort of potential or chemical energy, thus leaving less kinetic energy (motion of particles in system). That is manifested as a lowering of temperature.

 

[zenterix]

Congratulations, you have just learned ChatGPT is not reliable. Simply don't ask it such questions and don't use it as a part of the learning process.

I feel like the problem boils down to lousy use of the word "surroundings".

During the endothermic adiabatic process energy is consumed by the system, but the only source of the energy is the system itself, not its "surroundings" (from which it is isolated). So if the energy is used, it is the internal energy of the system itself, and the temperature of the system goes down, in a way it "eats" itself.

However, assuming the system consist of many molecules, if you look at a single molecule within the system, it absorbs the heat for its own surroundings - that is, from other molecules within the system.

Thanks for you answer but your opinion on chatgpt is just that, your opinion. It is unreliable, but this is not by any stretch equivalent to not being useful in various scenarios including the learning process.

 

[berkeman]

Thread is paused for a bit while the OP is reminded of the PF rules on AI chatbot use in the technical forums...