When 1.3584 g of sodium acetate trihydrate was mixed into 100.0 cm3 of 0.2000 M HCl(aq) at 25oC in a solution calorimeter, its temperature fell by 0.397oC on account of the reaction:
H3O+(aq) + NaCH3CO2·3 H2O(s) ? Na+(aq) + CH3COOH(aq) + 4 H2O(l)
The heat capacity of the calorimeter is 91.0 J K-1 and the heat capacity of the liquid solutions is 4.144 J K-1 cm-3. The heat of formation of the aqueous hydronium ion (H3O+(aq)) is the same as the aqueous hydrogen ion (H+(aq)). Determine the standard enthalpy of formation of the aqueous sodium ion. The standard enthalpy of formation of solid sodium acetate trihydrate is -1604 kJ mol-1