Free energy of fusion

In section 3.6.3 we mentioned that in growth on a curved face the strain surface free energy os takes the role the lateral surface free energy tr played in the flat surface case, namely that of a barrier to the formation of the first stem. This analogy cannot be made since, in contrast to surface free energy is associated with the deposition of any stem. Therefore and because of its physical origin (the volume strain) it is closely linked with the free energy of fusion. This is... 

Free energy of fusion per mole of polymer units. 

The chemical potential of the polymer is affected by "impurities" such as solvents or copolymerized units. For an equilibrium condition in the presence of water as the diluent, the melting temperature of starch (Tm) would be lower because p in the presence of diluent is less than pi). For the starch-water system at equilibrium, the difference between the chemical potentials of the crystalline phase and the phase in the standard state (pure polymer at the same temperature and pressure) must be equal to the decrease in chemical potential of the polymer unit in solution relative to the same standard state (Flory, 1953). By considering the free energy of fusion per repeating unit and volume fraction of water (diluent), the... 

Why is the excess free energy of a solid, G,f, negative How is G, related to the free energy of fusion, A G, How does Gf% change with temperature At which temperature is Gf% equal to zero ... 

When considering the solubility of a solid organic compound in water, conceptually we can imagine first converting it to the liquid state and then proceeding as above for a liquid compound. The free energy cost involved in the solid-to-liquid conversion is referred to as the free energy of fusion, (Chapter 4). This entity can be derived... 

If the temperature is not much lower than the true melting point (Tm), the free energy of fusion can be estimated by the following equation ... 

Find activity of copper in the alloy of the solidus composition, relative to the pure solid copper standard state. The standard free energy of fusion of copper is given by... 

If the assumption that the heat capacities of the pure liquid and solid A are equal is unwarranted, the expression for the standard free energy of fusion of A at T must be corrected ... 

Figure 12 The apparent 1 bar free energy of fusion of hypothetical REEMgAlSi06 clinopyroxene plotted as a function of temperature. Experimental data for all REE and Y were used and D values were corrected to. Results were fitted to Equation (24). Key Gallahan and Nielsen (1992), Watson et al. (1987), Blundy (unpublished data), X Hart and Dunn (1993), O Hack et al (1994), Grutzeck et al (1974), Gaetani and Grove (1995), O Hauri et al (1994), A Dunn (1986), Jones and Burnett (1987), McKay et al (1986), + McKay et al (1994), A Nicholls...

Change in the molar heat capacity of a polymer upon undergoing the glass transition. Gibbs free energy of fusion (melting). 

The solubility of solids, for example, an antioxidant, in a polymer are affected by the additional contribution of their free energy of fusion. This effect may be combined with Equation 1 to obtain the following prediction of solubility, 4>j, at unit activity of the solid (11) ... 

FIGURE 9.1 The chemical potential of paracetamol in CCl at varying concentrations (in mole fractions x) at 298 K. The intersection with the solid-state chanical potential defines the solid-liquid equilibrium (SLE) and corresponds to the solnbiUty of the dmg in this particnlar solvent. The difference between the pure liquid and the solid-state chemical potential is the free energy of fusion Also shown is the liquid-liquid equilibrium (LLE) where the virtually supercooled liquid is at equilibrium with the dissolved drug. 

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