compressed gas....and heat transfer...

[ProtoBob]

If you were to take a cylinder of air, at room temp, and lets say it is 100ml in volume.
If you were to take this cylinder of air, compress its volume to half its size, how much heat
would that create (btu's) and if the heat were to dissipate, would the air inside the cylinder then be back at atmospheric pressure?

If not back at atmospheric pressure, and (assuming there is still some pressure) the air were
then released, would it reabsorb the energy that was dissipated after it was compressed? i.e. would it then cool the surrounding room back to the original temperature?

Thanks!

[stewartcs]

If you were to take a cylinder of air, at room temp, and lets say it is 100ml in volume.
If you were to take this cylinder of air, compress its volume to half its size, how much heat
would that create (btu's) and if the heat were to dissipate, would the air inside the cylinder then be back at atmospheric pressure?

If not back at atmospheric pressure, and (assuming there is still some pressure) the air were
then released, would it reabsorb the energy that was dissipated after it was compressed? i.e. would it then cool the surrounding room back to the original temperature?

Thanks!

Heat is not created (heat is a transfer mechanism for energy across a boundary), although there would be an increase in the temperature of the gas due to the compression along with the pressure increase. If the cylinder is non-adiabatic then energy would be lost due to heat transfer to the surroundings. This would result in a slight pressure loss but not back to atmospheric pressure.

Irreversibilities are never recoverd from a system once incurred. The air would be heated once released from the cylinder so it would "re-absorb" some of the heat energy.

CS