Iron oxide reacts with aluminum in an exothermic reaction. Fe₂O₃(s) + 2Al(s) → 2Fe(s) + Al₂O₃(s)
The reaction of 5.00 g Fe₂O₃ with excess Al evolves 26.6 kJ of energy in the form of heat.Calculate the enthalpy change per mole of Fe₂O₃ reacted.

Question

Quizplus · Accepted Answer

First, identify the molar mass of Fe2O3: (55.85*2) + (16*3) = 159.7 g/mol. Given that 5.00 g of Fe2O3 reacts to release 26.6 kJ, we find the moles of Fe2O3: 5.00 g / 159.7 g/mol = 0.0313 mol. The enthalpy change per mole is then 26.6 kJ / 0.0313 mol = 850 kJ/mol, or -8.50 × 10^2 kJ, since the reaction is exothermic.

Iron Oxide Reacts with Aluminum in an Exothermic Reaction