A 3.00 L flаsk initiаlly cоntаins 0.325 mоles оf Cl2 and 0.436 moles of H2O. When the contents of the flask reach equilibrium, O2 is present in a concentration of 0.0350 M. What is the equilibrium concentration of H2O (g) ? 2 Cl2(g) + 2 H2O(g) ⇌ 4 HCl(g) + O2(g)