Question

The heat evolved in a reaction of 7.5 g of Fe₂O₃ with enough CO is 1.164 kJ.

Calculate ΔH for the reaction,

Fe₂O_3(s) + 3CO_(g) → 2Fe_(s) + 3CO_2(g)

Answer 1

Fe₂O_3(s) + 3CO_(g) → 2Fe_(s) + 3CO_2(g)

ΔH = -1.164 kJ

Atomic mass of Fe = 56 g mol^-1

Atomic mass of O = 16 g mol^-1

Mass of Fe₂O₃ = 7.5 g

ΔH = -1.164 kJ

ΔH⁰ for reaction = ?

Molar mass of Fe₂O₃ = 2 × 56 + 3 × 16

= 160 g mol^-1

∵ For 7.5 g Fe₂O₃ ΔH= – 1.164 kJ

∴ For 160 g Fe₂O₃

ΔH⁰ = \(\frac{-1.164\times 160}{7.5}\)

= -24.86 kJ mol^-1

∴ ΔH⁰ for the reaction = -24.83 kJ mol^-1