Internal and thermal energy vs Temp?

AI Thread Summary
Internal energy and thermal energy are distinct concepts in thermodynamics, with temperature being a measure of the average kinetic energy of particles. In an adiabatic free expansion of an ideal gas, the temperature remains constant, and therefore, the internal energy does not change since no work is done and no heat is exchanged. The states of the gas before and after expansion are not equivalent in terms of their physical arrangement, although their internal energy remains the same. Regarding the phase change from ice to water at 0°C, the latent heat energy indicates that ice has a lower thermal energy compared to liquid water, reflecting the energy required for the phase transition. Understanding these principles is crucial for grasping the behavior of gases and phase changes in thermodynamics.
Austin0
Messages
1,160
Reaction score
1
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
 
Science news on Phys.org


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.
 
I need to calculate the amount of water condensed from a DX cooling coil per hour given the size of the expansion coil (the total condensing surface area), the incoming air temperature, the amount of air flow from the fan, the BTU capacity of the compressor and the incoming air humidity. There are lots of condenser calculators around but they all need the air flow and incoming and outgoing humidity and then give a total volume of condensed water but I need more than that. The size of the...
Thread 'Why work is PdV and not (P+dP)dV in an isothermal process?'
Let's say we have a cylinder of volume V1 with a frictionless movable piston and some gas trapped inside with pressure P1 and temperature T1. On top of the piston lay some small pebbles that add weight and essentially create the pressure P1. Also the system is inside a reservoir of water that keeps its temperature constant at T1. The system is in equilibrium at V1, P1, T1. Now let's say i put another very small pebble on top of the piston (0,00001kg) and after some seconds the system...
Back
Top