Internal and thermal energy vs Temp?

[Austin0]

Internal and thermal energy vs Temp?

Hello I am a layman who is seriously trying to grasp the concepts and principles of physics to understand the workings of the world.
I have seen the equations for deriving Internal Energy and Thermal Energy but lack the math to apply them or be sure if I have got the concepts.
A couple of examples would be very helpful as reading hasnt brought certainty

SO if there is a volume of intermolecularly positive gas say, Oxygen ,that has been allowed to reach environmental temp [under the inversion temp] and it is then adiabatically expanded into a vacuum :
1 the temp would drop. COrrect??

2 What would be the Internal energy evaluation of the two states , compressed vs expanded? Would the internal energy level also drop or would the two states be equivalent?

3 Same question regarding the Thermal energy evaluation.

As there would be no work done and no system loss to the environment , logically I would assume the two states would be equivalent but am unsure of this.

Also regarding Ice and H2O at 0 C. Would the difference in latent heat energy show up as a lower internal/thermal energy level for the ice?

I know these questions may be elementary but they have plagued me for some time and any help would be very appreciated. Thanks

 

[FranzDiCoccio]

If the gas is ideal, there is no change in the temperature after an adiabatic free expansion. The internal energy stays the same as well (no work done, no heat exchanged...).
But I would not say that the states are equivalent, although I'm not sure what you mean by "equivalent".

I do not know what you mean by "intermolecularly positive gas" either, but sounds like you're
thinking of the "Joule free expansion experiment". Plenty of information on the web, and in textbooks of course.

 

[astrokreng]

Hello,

Thank you for your interest in physics and your questions about internal and thermal energy.

Internal energy refers to the total energy of a system, including the kinetic and potential energy of its particles. It is a state function, meaning it only depends on the current state of the system and not on how it got there.

Thermal energy, on the other hand, is the energy associated with the temperature of a system. It is a measure of the average kinetic energy of the particles in the system.

To answer your first question, when a gas is adiabatically expanded, the temperature will decrease. This is because the gas is doing work on its surroundings, causing its internal energy to decrease. This decrease in internal energy results in a decrease in temperature.

For your second question, the internal energy of the compressed gas will be higher than the expanded gas, as it has more kinetic and potential energy due to its higher temperature and pressure. The two states are not equivalent.

Similarly, the thermal energy of the compressed gas will also be higher than the expanded gas, as it is a measure of the average kinetic energy of the particles. However, the difference in thermal energy between the two states may not be significant, depending on the specific conditions.

Regarding your question about ice and water at 0°C, the difference in latent heat energy will indeed result in a lower internal and thermal energy for the ice. This is because the latent heat energy is used to break the bonds between water molecules, resulting in a decrease in the average kinetic energy of the particles.

I hope this helps clarify the concepts of internal and thermal energy for you. Keep exploring and asking questions, and you will continue to deepen your understanding of physics.