A pure calcium borate mineral,4CaO·5B 2 O 3 ·7H 2 O,was synthesized by phase transformation of double salt under hydrothermal condition and characterized by XRD,IR and chemical analysis.The molar enthalpy of...A pure calcium borate mineral,4CaO·5B 2 O 3 ·7H 2 O,was synthesized by phase transformation of double salt under hydrothermal condition and characterized by XRD,IR and chemical analysis.The molar enthalpy of solu - tion for4CaO·5B 2 O 3 ·7H 2 O in approximately1mol·L -1 HCl was determined.The standard molar enthalpy of for - mation-(11658.74 ± 8.93)kJ·mol -1 for4CaO·5B 2 O 3 ·7H 2 O was obtained from this result,measured enthalpies of solution of H 3 BO 3 in1mol·L -1 HCl(aq.),of CaO in(HCl+H 3 BO 3 )aqueous solution,and the standard molar en- thalpies of formation of CaO(s),H 3 BO 3 (s)and H 2 O(l).展开更多
文摘A pure calcium borate mineral,4CaO·5B 2 O 3 ·7H 2 O,was synthesized by phase transformation of double salt under hydrothermal condition and characterized by XRD,IR and chemical analysis.The molar enthalpy of solu - tion for4CaO·5B 2 O 3 ·7H 2 O in approximately1mol·L -1 HCl was determined.The standard molar enthalpy of for - mation-(11658.74 ± 8.93)kJ·mol -1 for4CaO·5B 2 O 3 ·7H 2 O was obtained from this result,measured enthalpies of solution of H 3 BO 3 in1mol·L -1 HCl(aq.),of CaO in(HCl+H 3 BO 3 )aqueous solution,and the standard molar en- thalpies of formation of CaO(s),H 3 BO 3 (s)and H 2 O(l).
