Tamil Nadu Board of Secondary EducationHSC Science Class 11

Calculate the enthalpy change for the reaction FeX2OX3+3CO⟶2Fe+3COX2 from the following data. 2Fe+32OX2⟶FeX2OX3; ΔH = −741 kJ C+12OX2⟶CO; ΔH = −137 kJ C+OX2⟶COX2; ΔH = − 394.5 kJ - Chemistry

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Numerical

Calculate the enthalpy change for the reaction \[\ce{Fe2O3 + 3CO -> 2Fe + 3CO2}\] from the following data.

\[\ce{2Fe + 3/2O2 -> Fe2O3}\]; ΔH = −741 kJ

\[\ce{C + 1/2O2 -> CO}\]; ΔH = −137 kJ

\[\ce{C + O2-> CO2}\]; ΔH = −394.5 kJ

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Solution

∆Hf (Fe2O3) = −741 kJ mol−1

∆Hf (CO) = −137 kJ mol−1

∆Hf (CO2) = −394.5 kJ mol−1

\[\ce{Fe2O3 + 3CO -> 2Fe + 3CO2}\]

ΔHr = ?

ΔHr = `Σ (Δ"H"_"f")_"products" − Σ (Δ"H"_"f")_"reactants"`

ΔHr = [2 ∆Hf (Fe) + 3 ∆Hf (CO2)] – [∆Hf (Fe2O3) + 3∆Hf (CO)]

ΔHr = [0 + 3 (−394.5)] − [−741 + 3 (−137)]

ΔHr = [−1183.5] − [−1152]

ΔHr = −1183.5 + 1152

ΔHr = −31.5 kJ mol−1

Concept: Enthalpy (H)
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Chapter 7: Thermodynamics - Evaluation [Page 226]

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Tamil Nadu Board Samacheer Kalvi Class 11th Chemistry Volume 1 and 2 Answers Guide
Chapter 7 Thermodynamics
Evaluation | Q II. 40. | Page 226

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