AP Chemistryhardmcq1 pt
Why do elements have nonzero standard molar entropies while ΔH°_f = 0?
A.The third law gives absolute entropies, not reference zeros
B.Elements store heat energy
C.Entropy is a state function
D.Tables are approximate
Explanation
Core Concept
The third law anchors S = 0 only at 0 K for a perfect crystal; every substance at 298 K has positive S°. Enthalpy formation is defined relative to elements, but entropy has an absolute scale.
Correct Answer
AThe third law gives absolute entropies, not reference zeros
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