Question

66. Perfect crystals of carbon monoxide (CO) are difficult to prepare because the very small dipole momet allows a few molecules to align in a pattern such as CO OC CO instead of CO CO CO. If such disordered crystals were cooled to 0 K, what would be the value of their absolute entropy? a. > 0 b. = 0 c. < 0 d. > 0, = 0, or < 0, depending on how carefully it was cooled e. > 0 or = 0, depending on how carefully it was cooled AVA

Answer 1

The question is based on 3rd law of thermodynamics. At absotute zero temp. (Ok), all motions stop, So, compound must be in perfectly ordered state. The absolute entropy should be o. But in case of co, since it can occupy or possess more than 1 structure re Со со соос осос cococo oc oc oc So, absolute entropy is not Z ero. It has Some value of entropy - which is called Residual entropy. Conclusion: a ✓ absolute entropy > 0 cococo OC oc oc