question_answer 1)

  Standard molar enthalpy of formation, \[{{\Delta }_{f}}{{H}^{O-}}\] is just a special case of enthalpy of reaction\[{{\Delta }_{r}}{{H}^{O-}}\]. Is the\[{{\Delta }_{r}}{{H}^{O-}}\]for the following reaction same as\[{{\Delta }_{f}}{{H}^{O-}}\]? Give reason for your answer. \[CaO(s)+C{{O}_{2}}(g)\to CaC{{O}_{3}}(s);\]      \[{{\Delta }_{f}}{{H}^{O-}}=-178.3\,kJ\,mo{{l}^{-1}}\]

Answer:

  The reaction: \[CaO(s)+C{{O}_{2}}(g)\to CaC{{O}_{3}}(s)\] It is not the equation of formation of \[CaC{{O}_{3}}(s)\]. Formation is the process in which a compound is formed from its constituent elements in their standard state.