Adiabatic Process: No Energy Change but Temperature Change?

[EIRE2003]

In an Adiabatic Process no heat energy is trasferred into or out of the system so there is no energy change, BUT, there is a change in pressure, volume and temperature.

But when atoms or molecules gain/loose heat energy they vibrate more/less respectively. And the measure of the vibration of the atoms/molecules is the temperature, am I right? So my question is Why is there no energy change but a temperature change?

Thanks

 

[Andrew Mason]

In an Adiabatic Process no heat energy is trasferred into or out of the system so there is no energy change, BUT, there is a change in pressure, volume and temperature.

But when atoms or molecules gain/loose heat energy they vibrate more/less respectively. And the measure of the vibration of the atoms/molecules is the temperature, am I right? So my question is Why is there no energy change but a temperature change?

Thanks

There is an energy change. It is a change to the internal energy of the gas. The energy change is equal to the amount of work done by or to the gas.

This is an area that causes confusion. Prof. Zemansky would say that you should not talk about heat as distinct from internal energy. This is probably a good idea, but that is not yet the way thermodynamics is taught.

AM

 

[charng]

for your question. You are correct that in an adiabatic process, there is no transfer of heat energy into or out of the system. However, there can still be a change in temperature due to the work being done on or by the system. This work can cause the molecules to vibrate more or less, leading to a change in temperature.

The key concept here is that temperature is not the only measure of energy. In an adiabatic process, the energy in the system is conserved, but it can be converted into different forms such as work or changes in pressure and volume. So while there may not be a direct transfer of heat energy, there can still be a change in the overall energy of the system.

Additionally, it's important to note that temperature is not solely determined by the vibration of atoms or molecules. Other factors such as the number and type of particles in the system, as well as the specific heat capacity, can also play a role in determining the temperature.

Overall, an adiabatic process may not involve a direct transfer of heat energy, but there can still be a change in temperature due to the conservation and conversion of energy within the system.