What is the enthalpy of mixing for perfect gases?

The enthalpy of mixing for perfect gases is zero, which is reflected in the correct answer. This outcome arises from the fundamental characteristics of ideal gases. When two ideal gases are mixed, there are no interactions or forces between the gas molecules as they behave independently. Therefore, the process of mixing does not require or release any heat energy.

The absence of intermolecular forces means that the enthalpy, which accounts for internal energy and pressure-volume work, does not change upon mixing. In thermodynamic terms, the specific enthalpy remains constant when the gases are mixed, leading to a net enthalpy change of zero. This is an essential concept when studying gas behavior under ideal conditions, reinforcing the behavior of perfect gases as independent entities that do not influence each other energetically.

Other options suggest various enthalpic changes, such as a positive or different value, which do not apply in the context of ideal gas mixing. The foundational principle lies in the independence of gas behavior, resulting in no enthalpic change during mixing.