  Using the trace anomaly relation, low-energy theorem and Witten-Veneziano
formula, we have developed an analytical formalism which allows one to
calculate the gluon condensate, the topological susceptibility and the mass of
the $\eta'$ meson in the chiral limit as functions of the non-perturbative
vacuum energy density. It is used for numerical evaluation of the chiral QCD
topology within the QCD vacuum model consisting mainly of the quantum component
given by the recently proposed zero modes enhancement (ZME) model and the
classical component given by the the random instanton liquid model (RILM). We
sum up both contributions into the total, nonperturbative vacuum energy
density. A very good agreement with the phenomenological values of the
topological susceptibility, the mass of the $\eta'$ meson in the chiral limit
and the gluon condensate has been obtained. This puts the above mentioned QCD
vacuum model on a firm phenomenological ground.
