Which of the following is expected to have zero entropy
I. N₂(g) at 273 K
II. SiO₂(s, amorphous) at 0 K
III. NaCl(s) perfectly ordered crystal at 25 K
IV. Na(s) perfectly ordered crystal at 0 K

Question

Quizplus · Accepted Answer

Entropy measures the disorder or randomness in a system. According to the third law of thermodynamics, the entropy of a perfect crystal at absolute zero (0 K) is exactly zero because the system is in a state of perfect order. Among the options, only IV (Na(s) perfectly ordered crystal at 0 K) meets this criterion. All other options involve conditions or substances that do not meet the criteria for having zero entropy.

Which of the Following Is Expected to Have Zero Entropy