Calculate the standard enthalpy change for the following reaction.

Question

Using standard heats of formation, calculate the standard enthalpy change for the following reaction.

Fe₂O₃(s) + 3H₂(g)2Fe(s) + 3H₂O(g)

Answer 1

delta-H(rxn) = Sum of the heats of formation of the products - Sum of heats of formation of the reactants.

Products:

Fe(s) heat of formation = 0 (for an element in its natural state at STP)

H2O(g): -242 kJ/mol

Reactants:

Fe2O3(s) -824 kJ/mol

H2(g) zero

[2(0) + 3(-242)] - [(-824) + 0] = +98 kJ/mol