Why Statistical Thermodynamics?

In thermodynamics and kinetics, the thermal properties, the chemical reactivity, and the phase behaviors are described without reference to the molecular structure by a few macroscopic observables like \(p, V\) , and T. Material properties such as heat capacity \(c_V\) , thermal expansion coefficients \(\alpha \) , or reaction constants k are treated as empirical parameters, which cannot be analyzed further in this framework. Why the materials differ in these properties cannot be questioned, since the molecular structure – on which these differences are based – is not the subject of the description.