Which thermodynamic process describes a system that does not exchange heat with its environment?

An adiabatic process is defined as one in which there is no heat exchange between the system and its surroundings. In this type of process, any change in internal energy of the system is solely due to work done on or by the system. This can occur, for instance, when a gas expands or compresses rapidly enough that there is not enough time for heat to flow into or out of the gas, thereby leading to changes in temperature without any heat transfer.

In contrast, an isothermal process involves a constant temperature throughout the process, which is achieved by allowing heat to flow in or out of the system to compensate for any work being done. An isochoric process maintains a constant volume, and any change in internal energy also tends to involve heat transfer. Lastly, an isobaric process occurs at a constant pressure, which means heat can be exchanged to maintain that pressure during work done on or by the system.

Thus, the definition of the adiabatic process directly relates to the absence of heat transfer, making it the correct choice.