ABSTRACT
In Chapter 8, it was seen that the absence of interatomic forces between the atoms of ideal gases causes the enthalpy of mixing of ideal gases to be zero. This situation represents one extreme of a range of possible situations. Toward the other extreme of this range is the situation in which gases are mixed which exhibit marked chemical affinity for one another. For example, considerable heat is released when gaseous hydrogen and oxygen are mixed in the presence of a catalyst. The thermodynamics of such a system can be treated in either of two ways:
The mixture can be considered to be a highly nonideal mixture of H2 and O2, the thermodynamic equilibrium state of which, at a given temperature and pressure, can be defined in terms of the fugacities of the components H2 and O2.
It can be considered that the H2 and O2 have reacted with one another to some extent to produce the product species H2O.
