Melts heat capacity

Figure 3.20 (top) Arrhenius plots of the viscosity data with temperature scaled by Tg. and (bottom) ratio of melt heat capacity to that of crystal plotted against reduced temperature. (After Angell, 1995). 

With a typical specific gravity (p) equal to unity, a melt heat capacity Cp of 0.5 cal/g °C, and 10% efficiency (E) ... 

The melt heat capacity has been discussed by Wunderlich (1962). Fig. III. 16 shows an extrapolation of the separate heat capacity contributions. The filled circles indicate the heat capacity extrapolated from... 

Thermal property refers to the response of a material to the apphcation of heat. As a solid absorbs energy in the form of heat, its temperatnre rises and its dimensions increase. The energy may be transported to cooler regions of the specimen if temperature gradients exist, and nltimately, the specimen may melt. Heat capacity, thermal expansion, and thermal condnctivity are properties that are often critical in the practical use of solids. 

The most direct effect of defects on tire properties of a material usually derive from altered ionic conductivity and diffusion properties. So-called superionic conductors materials which have an ionic conductivity comparable to that of molten salts. This h conductivity is due to the presence of defects, which can be introduced thermally or the presence of impurities. Diffusion affects important processes such as corrosion z catalysis. The specific heat capacity is also affected near the melting temperature the h capacity of a defective material is higher than for the equivalent ideal crystal. This refle the fact that the creation of defects is enthalpically unfavourable but is more than comp sated for by the increase in entropy, so leading to an overall decrease in the free energy... 

The heat capacity can be computed by examining the vibrational motion of the atoms and rotational degrees of freedom. There is a discontinuous change in heat capacity upon melting. Thus, different algorithms are used for solid-and liquid-phase heat capacities. These algorithms assume different amounts of freedom of motion. 

A number of properties can be computed from various chemical descriptors. These include physical properties, such as surface area, volume, molecular weight, ovality, and moments of inertia. Chemical properties available include boiling point, melting point, critical variables, Henry s law constant, heat capacity, log P, refractivity, and solubility. 

The heat capacity of thiazole was determined by adiabatic calorimetry from 5 to 340 K by Goursot and Westrum (295,296). A glass-type transition occurs between 145 and 175°K. Melting occurs at 239.53°K (-33-62°C) with an enthalpy increment of 2292 cal mole and an entropy increment of 9-57 cal mole °K . Table 1-44 summarizes the variations as a function of temperature of the most important thermodynamic properties of thiazole molar heat capacity Cp, standard entropy S°, and Gibbs function - G°-H" )IT. 

Oxidizer Available oxygen Melting point, °C Density, g/cm Heat of formation, kj / mof Heat capacity, J/(mol-K) Gas, moles per 100 g"... 

Thermodynamic and physical properties of water vapor, Hquid water, and ice I are given ia Tables 3—5. The extremely high heat of vaporization, relatively low heat of fusion, and the unusual values of the other thermodynamic properties, including melting poiat, boiling poiat, and heat capacity, can be explained by the presence of hydrogen bonding (2,7). 

The Group 4—6 carbides are thermodynamically very stable, exhibiting high heats of formation, great hardness, elevated melting points, and resistance to hydrolysis by weak acids. At the same time, these compounds have values of electrical conductivity. Hall coefficients, magnetic susceptibiUty, and heat capacity in the range of metals (7). 

Figure 10.1 Thermal conductivities and heat capacities of the low-melting elements Na, Zn, Sn and Pb...

The heat capacity is largely determined by the vibration of die metal ion cores, and tlris property is also close to tlrat of tire solid at the melting point. It therefore follows tlrat both the thermal conductivity and the heat capacity will decrease with increasing teirrperamre, due to the decreased electrical conductivity and the increased amplitude of vibration of the ion cores (Figure 10.1). 

The physical properties of a flaimnable solid, such as hardness, texture, waxiness, particle size, melting point, plastic flow, tiiennal conductivity, and heat capacity, impart a wide range of cliaracteristics to tiie flanmiability of solids. A solid ignites by first melting and tiien producing sufficient vapor, which in turn mixes witii air to fonn a flaiimiable composition. 

Magnetic heat capacity of nickel, 133 Magnetic susceptibility, 25 Maleic anhydride, 168 Many electron system, correlations in, 304, 305, 318, 319, 323 Melting temperature and critical temperature for disordering correlation, 129... 

Specific Heats of Solid Mixtures.—The specific heat of a homogeneous solid mixture of solid components is not usually additively composed of the specific heats of the latter. W. Spring (1886) found that the total heat capacity of alloys of lead and tin was always greater than the sum of those of the components, but above the melting-point the two were equal. A. Bogojawlensky and N. Winogradoff (1908) find, however, that the heat capacities of the isomorphous mixtures ... 

Figure 4.4 Heat capacity of N as a function of temperature. A solid phase transition occurs at 35.62 K, the melting temperature is 63.15 K, and the normal boiling temperature is 77.33 K.

Figure 4.8 Heat capacity of glycerol as a function of temperature. The solid line indicates Cp,m for the liquid and glassy phase. The dashed line represents Cp m for the solid. The dotted line at the melting temperature of 291.05 K. indicates the change in heat capacity upon melting. A glass transition occurs in the supercooled liquid at approximately 185 K. The heat capacities of the solid and the glass approach one another as the temperature is lowered they are almost identical below 140 K.

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