The QCD+QED axial anomaly low-energy theorems are applied to estimate the accuracy of an instanton vacuum - based chiral quark model. The low-energy theorems give an exact relation between the matrix elements of the gluon and photon parts of the QCD+QED axial anomaly operator equation. The matrix elements between vacuum and two photon states and between vacuum and two gluon states are calculated for arbitrary N-f. It is shown that this model does satisfy the low-energy theorems with an accuracy of similar to 17%. We estimate also the contribution of the nonperturbative conversion of gluons into photons to the decay eta --> 2 gamma and compare with experimental data. (C) 1997 Published by Elsevier Science B.V.
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