  The classical mass action law in chemical kinetics is put into the context of
multiscale thermodynamics.Despite the purely dissipative character of the
classical mass action law, inertial effects also play a role in chemical
kinetics. Therefore, the kinetics is extended to an enlarged state space with
reaction rates as new state variables and bringing inertial effects. The
dynamics is then lifted to the Liouville description within kinetic theory on
the enlarged state space in order to include fluctuations. Subsequently, the
kinetic theory is reduced to its first and second moments, leading to a new
Grad-like hierarchy in chemical kinetics, expressing the multiscale nature of
the chemical kinetic with inertia. Dissipation within the extended state space
is proposed and it is shown to lead to the classical mass action law when the
moments relax to their respective quasi-equilibria. In particular, we
demonstrate the possibility of oscillating homogeneous chemical reactions and
how the correlations of fluctuations correspond with the chemical kinetics.
