From the data at `25^(@)C`:
`Fe_(2)O_(3)(s) +3C_(("graphite")) rarr 2Fe(s) + 3CO(g), DeltaH^(Theta) = 492.0 kJ mol^(-1)`
`FeO(s) +C_(("graphite")) rarr Fe(s) CO(g), DeltaH^(Theta) = 155.0 kJ mol^(-1)`
`C_(("graphite")) +O_(2)(g) rarr CO_(2)(g), DeltaH^(Theta) =- 393.0 kJ mol^(-1)`
`CO(g)+(1)/(2)O_(2)(g) rarr CO_(2)(g), DeltaH^(Theta) =- 282.0 kJ mol^(-1)`
Calculate the standard heat of formation of `FeSO(s)` and `Fe_(2)O_(3)(s)`.

Explanation

a. `Fe(s) +CO(g) rarr FeO(s) +C ("graphite"), DeltaH^(Theta) =- 155.0 kJ mol^(-1)`
b. `C_(("graphite"))+O_(2)(g) rarr CO_(2)(g), DeltaH^(Theta) =- 393.0 kJ mol^(-1)`
c. `CO_(2)(g)rarr CO(g) +(1)/(2)O_(2)(g), DeltaH^(Theta) = 282.0kJ mol^(-1)`
`ulbar( {:(,"On adding equation(a),(b),and (c),",,),(,"Fe(s)"+(1)/(2)(O_(2))(g)rarrFeO(s),,),(,,DeltaH^(Theta)=-266.0 kJmol^(-1),):})`
Similarly, way may calculate heat of formation of `Fe_(2)O_(3)`.