Question

The reaction between aluminum and iron (III) oxide is tremendously exothermic and produces enough heat to weld railway tracks together. The products of the reaction are iron (III) and aluminum oxide (Al2O3 ). b. How much heat is liberated when 3.21 g of iron (III) oxide are reduced by aluminum at constant pressure (at 298.15 K)?

Answer 1

The heat liberated will be 49.5 J

Explanation :

The reaction when iron (III) oxide is reduced by aluminum is given by :

2Al + Fe₂O₃ = Al₂O₃ + 2Fe

molecular weight of Fe₂O₃ is 160 gms

=> number of moles in 3.21 gms = 3.21/160 = 0.02

we know that heat liberated is given by,

ΔH = nRT

=> ΔH = 0.02 x 8.314 x 298.15

=> ΔH = 49.5 Joules

Hence the heat liberated when 3.21g of iron (III) oxide are reduced by aluminum will be 49.5 J