An ideal gas is compressed isothermally from 30 L to 20 L. During this process, 6.0 J of energy is expended by the external mechanism that compressed the gas. What is the change of internal energy for this gas?

A gas is expanded to twice its original volume with no change in its temperature. This process is:

A refrigerator removes heat from the freezing compartment at the rate of 20 kJ and ejects 24 kJ into a room per cycle. How much work is required in each cycle?

The efficiency of a heat engine is defined as the ratio of:

During an isothermal process, 5.0 J of heat is removed from an ideal gas. What is the change in internal energy?