| Popis: |
The heat capacity of CuFeS2 (chalcopyrite) was measured between 6.3 and 303.5 K. At 298.15 K, Cp,mo and Smo(T) are (95.67±0.14) J·K−1·mol−1 and (124.9±0.2) J·K−1·mol−1, respectively. From a consideration of the results of two sets of equilibrium measurements we conclude that ΔfHmo(CuFeS2, cr, 298.15 K) = −(193.6±1.6) kJ·mol−1 and that the recent bomb-calorimetric determination by Johnson and Steele (J. Chem. Thermodynamics 1981, 13, 991) is in error. The standard molar Gibbs free energy of formation of bornite (Cu5FeS4) is −(444.9±2.1) kJ·mol−1 at 748 K. |
