Consider the reaction: 2al(s) + fe2o3(s) → al2o3(s) + 2fe(s) the δhf for fe2o3(s) = -824.3 kj/mole. the δhf for al2o3(s) = -1675.7 kj/mole. finish the equation. δhrxn = [(1)( kj/mole) + (2)( kj/mole)] - [(1)( kj/mole) + (2) ( kj/mole)]

ΔHrxn = [(1) x (-1675.7 kJ/mole) + (2) x (0 kJ/mole)] - [(1) x (-824.3 kJ/mole) + (2) x (0 kJ/mole)] = -1675.7 kJ/mole + 824.3 kJ/mole = -851.4 kJ/mole.

Explanation:

To calculate ΔH of the reaction, we use the mathematical relation:ΔHrxn = ∑ΔHproducts - ∑ΔHreactants.So, ΔHrxn = [(n x ΔHf for Al₂O₃) + (n x ΔHf for Fe)] - [(n x ΔHf for Fe₂O₃) + (n x ΔHf for Al)]where n is the number of moles of each reactant.ΔHrxn = [(1) x (-1675.7 kJ/mole) + (2) x (0 kJ/mole)] - [(1) x (-824.3 kJ/mole) + (2) x (0 kJ/mole)] = -1675.7 kJ/mole + 824.3 kJ/mole = -851.4 kJ/mole.ΔHf for Al and Fe = 0.0 kJ/mole; since the heat for formation of elements that found in nature is equal 0.0 kJ/mole