Question
Account for the following:
(i) Why does real crystal have more entropy than an ideal crystal?
(ii) Why the entropy of a pure substance is taken as zero at absolute zero?
(iii) Why the entropy of the universe is continuously increasing?
Solution
(i) An ideal crystal has a perfect order of its constituent particles while a real crystal has less order because of some defects. Therefore, a real crystal has more entropy than an ideal crystal.
(ii) Because at 0K, there is a complete order in all the crystals and no randomness, therefore, entropy is taken as zero.
(iii) Because, in the universe, almost all processes are spontaneous and for all spontaneous processes, there is an increase in entropy.
