Question

When a gas is compressed using external pressure (piston-cylinder assembly) we say work is done on the gas and it increases the internal energy of the gas.

Where does this work mainly go ? Does it increase the Kinetic energy of the molecules (work energy theorem), does it increase the potential energy of the molecules since we are doing work against internal conservative intermolecular forces of the gas, or it goes to something else ?

Also can temperature of a gas be increased by work only ?

Answer 1

The work done on a compressed gas increases its internal kinetic energy, which raises its temperature and pressure; the increase in potential energy is usually minimal. Yes, the temperature of a gas can be raised by work alone.

Step-by-step explanation:

When a gas is compressed using a piston-cylinder assembly, work is done on the gas, which increases the internal energy of the gas. This work primarily goes into increasing the kinetic energy of the gas molecules according to the work-energy theorem, leading to an increase in temperature and pressure. It may also increase potential energy minimally as molecules are forced closer together.

However, in an ideal gas, the potential energy from intermolecular forces is often considered negligible. The temperature of a gas can indeed be increased by work alone, as evidenced by the process of compressing air in a bike tire, where work done to compress the gas increases the internal energy and temperature of the air without heat transfer.