複選題
52、 Which of the following statements are correct?
(A) The enthalpy of a compound is a state property and is therefore independent of the method by which the compound is prepared.
(B) The enthalpy of a compound is not a state property and is therefore dependent on the method by which the compound is prepared.
(C) For a reaction between chemical compounds the enthalpy change may be obtained as the difference between the enthalpies of formation of the products and the enthalpies of formation of the reactants, all not necessarily at the same temperature.
(D) For a reaction between chemical compounds the enthalpy change may be obtained as the difference between the enthalpies of formation of the products and the enthalpies of formation of the reactants, all at the same temperature.