Question

Given the following data:

2Fe(s) + 3CO2(g) → Fe2O3(s) + 3CO(g)	ΔH° = 23.0 kJ
3FeO(s) + CO2(g) → Fe3O4(s) + CO(g)	ΔH° = -18.0 kJ
3Fe2O3(s) + CO(g) → 2Fe3O4(s) + CO2(g)	ΔH° = -39.0 kJ

Calculate ΔH° for the reaction:
Fe(s) + CO₂(g) → FeO(s) + CO(g)

Answer 1

Lets number the reaction as 1, 2, 3, 4 from top to bottom

required reaction should be written in terms of other reaction

This is Hess Law

required reaction can be written as:

reaction 4 = (1/2) * (reaction 1) - (1/3) * (reaction 2) + (1/6) * (reaction 3)

So, deltaHo rxn for required reaction will be:

deltaHo rxn = (1/2) * deltaHo rxn(reaction 1) -(1/3) * deltaHo rxn(reaction 2) + (1/6) * deltaHo rxn(reaction 3)

= (1/2) * (23.0) - (1/3) * (-18.0) +(1/6) * (-39.0)

= 11.0 KJ

Answer: 11.0 KJ