材料期刊网

The molar enthalpies of solution of VOSO(4)center dot 3.52H(2)O( s) at various molalities in water and in aqueous sulfuric acid (0.1 mol.kg(-1)), Delta(sol)H(m), were measured by a solution-reaction isoperibol calorimeter at 298.15 +/- 0.01 K. An improved Archer's method to estimate the standard molar enthalpy of solution, Delta(sol)H(m)(0), was put forward. In terms of the improved method, the values of Delta(sol)H(m)(0) =- 24.12 +/- 0.03 kJ . mol(-1) of VOSO(4) +/- 3.52H(2)O(s) in water and Delta(sol)H(m)(0) = - 15.38 +/- 0.06 kJ . mol(-1) in aqueous sulfuric acid were obtained, respectively. The data indicates that the energy state of VOSO(4) in aqueous H(2)SO(4) is higher than that in pure water.