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COMEDK202510 May 2025Morning ShiftChemistryThermodynamics (C)Actual

For a reaction X ₂( l )+ Y ₂( ~g ) 2 XY ( g ) , the H ^0 and S ^0 are +29.3 ~kJ / mol and 104.1 ~J ~K ⁻¹ ~mol ⁻¹ respectively at 298 K . Find the free energy change in kJ / mol .

Options

  1. A2.04
  2. B5.2
  3. C0.6
  4. D1.72

Correct answer

D. 1.72

Step-by-step solution

The Gibbs free energy change G^0 is given by the relation G^0 = H^0 - T S^0 . Given values are H^0 = 29.3 kJ/mol and S^0 = 104.1 J K ⁻¹ mol ⁻¹ = 0.1041 kJ K ⁻¹ mol ⁻¹ at T = 298 K . Substituting these values into the equation: G^0 = 29.3 kJ/mol - (298 K 0.1041 kJ K ⁻¹ mol ⁻¹) G^0 = 29.3 - 31.0218 G^0 = -1.7218 kJ/mol . The magnitude of the free energy change is approximately 1.72 kJ/mol . Answer: 1.72

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