The standard enthalpy of formation of `FeO` and `Fe_(2)O_(3)` is `-65kcal mol^(-1)` and `-197kcal mol^(-1)` respectively. A mixture of two oxides contains `FeO` and `Fe_(2)O_(3)` in the mole ratio `2:1`. If by oxidation, it is changed into a `1:2` mole ratio mixture, how much of thermal energy will be released per mole of initial mixture ?

Answer

`-13.4kcal mol^(-1)`