  We derive the gas dynamics equations considering changes of velocity
distribution function on the scale of a molecule free path. We define the
molecule velocity distribution function in a specific form so that only
molecule velocities after intermolecular collisions in a chosen fixed volume
are taken into account. The obtained equations differ from the well-known
Navier-Stoks equations and contain the new terms. The continuity equation
includes the second derivatives of dynamical viscosity. The equation of
momentum conservation does not include the volume viscosity and the equation of
energy conservation describes the transformation of gas mass velocity into the
gas thermal energy. One can expect that these new equations of motion allow to
construct a description of macroscopic physical phenomena in more complicated
situations than the standard gas dynamics equations do.
