The given reaction is:
Fe2O3(s)+3CO(g)→2Fe(s)+3CO2(g)
The value of ΔH∘f,Fe2O3(s)=−825.50 kJ/mol
The value of ΔH∘f,CO(g)=−110.53 kJ/mol
The value of ΔH∘f,CO2(g)=−393.52 kJ/mol
The enthalpy of a reaction is given by
ΔH∘=∑vpΔH∘f,p−∑vrΔH∘f,p
where, vp is the stoichiometric coefficient of the product an the reactant;
ΔH∘f is the standard enthalpy of formation of a substance.
Putting the values of ΔH∘f for each compound in the given reaction, we can calculate the enthalpy of formation for the reaction as follows :
ΔH∘=[2×0+3×(−393.52)]−[1×(−825.50)+3×(−110.53)]
⇒ΔH∘=(0−1180.56+825.50+331.59) kJ/mol
⇒ΔH∘=−23.47 kJ/mol
Therefore, the value of ΔH∘ for the given reaction is −23.47 kJ/mol.