The explicit relations between the thermodynamic functions of the lattice gas model and the fluid within the framework of an approach proposed earlier [Kulinskii, V. L. J. Phys. Chem. B 2010, 114, 2852] are derived. It is shown that the Widom line serves as the natural border between the gas-like and the liquid-like states of the fluid. The explanation of the global cubic form of the binodal for the molecular liquids is proposed, and the estimate for the amplitude of the binodal opening is obtained.