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MHT CET202519 Apr 2025Morning ShiftChemistryThermodynamics (C)Actual

Calculate S total for a certain reaction at 298 K if H ^ =-208.6 ~kJ and S^ =-36 J⁻¹

Options

  1. A664 JK ⁻¹
  2. B834 JK ⁻¹
  3. C926 JK ⁻¹
  4. D736 JK ⁻¹

Correct answer

A. 664 JK ⁻¹

Step-by-step solution

The total entropy change is determined by summing the system and surroundings contributions: S_ total = S_ system + S_ surroundings . The entropy change of the surroundings is calculated from the enthalpy change: S_ surroundings = - H_ system T . Given H^ = -208.6 10^3 J and T = 298 K , S_ surroundings = - -208.6 10^3 298 = 700 JK ⁻¹ . The total entropy change becomes: S_ total = -36 + 700 = 664 JK ⁻¹ . This value corresponds to option A . The correct choice is A .

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