Thermodynamic Properties at Absolute Zero

To calculate for this transition, it is necessary to have heat capacity data for both glassy and crystaUine glycerol from near 0 K to the melting point and the heat of fusion of both glass and crystal. Such data [7] lead to a ASm for Equation (11.7) of 19.2 J K mol. Thus, glassy glycerol cannot be assigned zero entropy at OK rather, it possesses a residual entropy of 19.2 J moP.  

Many substances can exist in two or more crystalline forms at low temperatures. Of course, one form is more stable than the others. Nevertheless, if each is a perfect crystalline substance, the entropy of each will be zero at 0 K. For example, for the transition 

OK can be computed from heat capacity measurements [8] for each crystalline form from near 0 K to the transition temperature (368.6 K) and the heat of transition. The result is zero within experimental error. Hence, both rhombic and monoclinic sulfur ate assigned zero entropy at 0 K. 

From the third law of thermodynamics, it is possible to derive several limiting relationships for the values of thermodynamic quantities at absolute zero for perfect crystalline substances. 

It follows from the definition of the Gibbs function. Equation (7.17), that 

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