  We investigate the difference between hadron resonance gas (HRG) calculations
for chemical freeze-out parameters at fully and partly chemical equilibria. To
this end, the results are compared with the particle ratios measured in central
Au-Au collisions at a wide range of nucleon-nucleon center-of-mass energies,
\hbox{$\sqrt{s_{NN}}=7.7-200 $GeV} as offered by the STAR experiment. We
restrict the discussion to STAR, because of large statistics and overall
homogeneity of STAR measurements (one detector) against previous experiments.
We find that the matter produced at these energies is likely in fully chemical
equilibrium, which is consistent with recent lattice QCD results. The possible
improvements by partial chemical equilibrium ($\gamma_S\neq 1$) are very
limited. We also discuss these results with the ones deduced from $\phi/\pi^-$
and $\Omega^-/\pi^-$ ratios. These hadron ratios are sensitive to the degree of
chemical equilibrium. Accordingly, the conclusion that the matter produced
reaches fully chemical equilibrium in central Au-Au at RHIC energies is
confirmed.
