Calculate S_ total for a certain reaction if H=-150 ~kJ and S=32 JK ⁻¹ at 300 K .

Step-by-step solution

The total entropy change for a reaction combines system and surroundings contributions: S_ total = S_ system + S_ surroundings . The entropy change of the surroundings follows from the enthalpy change at constant temperature: S_ surroundings = - H T . Given H = -150 10^3 J and T = 300 K , substitution yields S_ surroundings = - -150 10^3 300 = 500 JK ⁻¹ . Adding the system entropy change S_ system = 32 JK ⁻¹ gives S_ total = 32 + 500 = 532 JK ⁻¹ . The value 532 JK ⁻¹ corresponds to option B .