Entropy associated with phase transformations

ENTROPY CHANGES ASSOCIATED WITH PHASE TRANSFORMATIONS... 

However, the difference A /z -A /z represents the enthalpy A /z° accompanying the phase change of the component in question between P and P . Similarly, the difference A 5°-A 5 represents the opposite of entropy associated with the same transformation. The slope of the straight line PP is therefore given by the opposite of the ratio of the enthalpy of phase change of the compound involved to the corresponding entropy ... 

In other cases, an unfavorable enthalpy term was found to be compensated by a favorable entropy term, thus rendering negative the free energy change associated with a particular phase transformation. Lamivudine can be obtained in two forms, one of which is a 0.2-hydrate obtained from water or from methanol that contains water and the other of which is non-solvated... 

Many of the changes which occur in solids are not profound enough to impose a new space lattice and thereby to reveal themselves as polymorphic phase transformations. They may depend upon alterations of configuration of the statistical kind exemplified by the copper-zinc alloy and the abnormality m the specific heat with which they are associated is connected with the increased potential energy imposed by the more random arrangement. The heat absorption is due primarily, not to the excitation of new degrees of freedom, but to the increase in configurational entropy. 

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