Solid sodium peroxide (Na2O2) reacts with liquid water yielding aqueous sodium hydroxide and oxygen gas. How much heat is released when 250.0 L of oxygen gas is produced from the reaction of sodium peroxide and water if the reaction is carried out in an open container at 1.000 atm pressure and 25C?
(Given: Hf[Na2O2(s)] = 510.9 kJ/mol; Hf[NaOH(aq)] = 469.2 kJ/mol; Hf[H2O(l)] = 285.8 kJ/mol)