What is the entropy change of the surroundings (ΔSsurr) when an exothermic reaction releases 600 J of heat to the surroundings at a constant temperature of 300 K?
Answer and explanation
Correct answer: B. +2.0 J/K
- Step 1: For a process occurring at constant temperature and pressure, the heat absorbed by the surroundings () is equal in magnitude and opposite in sign to the heat of reaction (): .
- Step 2: The system releases , so , which means the surroundings absorb heat: .
- Step 3: The entropy change of the surroundings is defined as: .
Answer
+2.0 J/K
Why not the others: '-2.0 J/K' inverts the sign, representing heat loss from the surroundings; '+1.8 * 10^5 J/K' erroneously multiplies heat by temperature () instead of dividing; 'Zero' is false because the surroundings absorb thermal energy.
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