alleryStart learning →How much heat must transfer energy into a system at 400 K to produce an entropy change of 35 J/K?
A1.4 x 10^1 J
B1.4 x 10^2 J
C1.4 x 10^3 J
D1.4 x 10^4 J
Answer & Solution
Correct answer: D. 1.4 x 10^4 J
1. Rearranging ΔS = Q divided by T for heat gives Q = ΔS multiplied by T.
2. Substitute ΔS = 35 J/K and T = 400 K.
3. Multiplying gives Q = 35 x 400 = 14,000 J, which is 1.4 x 10^4 J.
4. 1.4 x 10^3 J is ten times too small, and 1.4 x 10^1 J and 1.4 x 10^2 J are a thousand and a hundred times too small.
5. So 1.4 x 10^4 J is correct.
_Source: OpenStax Physics (CC BY 4.0), Ch 12 "Thermodynamics", section 12.3 Second Law of Thermodynamics: Entropy_
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