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The Enthalpy of combustion of C ₆ H ₅ COOH ( s ) at 25^ c and 1.0 atm pressure is -2546 ~kJ / mol . What is the Internal energy change for this reaction?

Options

  1. A-2552.2 ~kJ
  2. B-2544.8 ~kJ
  3. C-2560.3 ~kJ
  4. D-2539.8 ~kJ

Correct answer

B. -2544.8 ~kJ

Step-by-step solution

C₆H₅COOH(s) + 15 2 O₂(g) 7CO₂(g) + 3H₂O(l) n_g = 7 - 15 2 = -0.5 mol U = H - n_g RT = -2546 - (-0.5 8.314 10⁻³ 298) U = -2546 + 1.2388 = -2544.8 kJ

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