Sodium chloride heat capacity

Brunauer and co-workers [129, 130] found values of of 1310, 1180, and 386 ergs/cm for CaO, Ca(OH)2 and tobermorite (a calcium silicate hydrate). Jura and Garland [131] reported a value of 1040 ergs/cm for magnesium oxide. Patterson and coworkers [132] used fractionated sodium chloride particles prepared by a volatilization method to find that the surface contribution to the low-temperature heat capacity varied approximately in proportion to the area determined by gas adsorption. Questions of equilibrium arise in these and adsorption studies on finely divided surfaces as discussed in Section X-3. 

Figure 12.3 Density and specific heat capacity (a) Sodium chloride, (b) Calcium chloride...

Silvester, L. F. Pitzer, K. S. "Thermodynamics of Electrolytes. 8. High-Temperature Properties, Including Enthalpy and Heat Capacity with Application to Sodium Chloride" J. Phys. Chem., 1977, 81, 1822. 

Allred G. C. and Woolley E. M. (1981). Heat capacities of aqueous acetic acid, sodium acetate, ammonia, and ammonium chloride at 283.15 K, 298.15 K, and 313.15 K ACfp for ionization of acetic acid and for dissociation of ammonium ion. J. Soln. Chem., 14 549-560. 

L. F. Silvester and K. S. Pitzer, Thermodynamics of electrolytes. 8. High-temperature properties, including enthalpy and heat capacity, with application to sodium chloride , J. Phys. Chem., 81, 1822-1828 (1977). 

In an autoclave of 1-liter capacity, without stirrer, and heated by an oil bath, is placed 600 cc. dry methyl alcohol in which 23 grams of metallic sodium has previously been dissolved (reflux condenser), and to this is added 158 grams of pure o-nitrochlorobenzene (m.p. about 32°C. b.p. 243°). The autoclave is sealed and the heating is started. The temperature is raised to 120° over a period of 1 hour, held at this point for 3 hours, and finally held at 128° for 1 hour more. The pressure is 8 to 10 atmospheres. At the end of the reaction, the methyl alcohol is blown out through the valve into a good condenser. The recovered methyl alcohol can be used without purification in a subsequent run. The reaction product is removed from the autoclave, washing the latter out with hot water to remove the sodium chloride. The crude product is washed twice with five times its volume of hot water, separated, and distilled in vacuum. The yield is 136 grams, or 88 per cent of the theoretical amount. The product boils at 141° at 15 mm. 

Protein thermal stabilities were determined by monitoring the circular dichroism at 223 nm as a function of sample temperature (Eriksson et al., 1993 Zhang et al., 1995). The buffer was 0.1 M sodium chloride, 1.4 mM acetic acid, 8.6 mM sodium acetate, pH 5.42, with protein present at 15 to 30 /tg/ml. The melting temperature, T , of WT was 65.3°C. Free energy values were computed at 59°C assuming a constant change in heat capacity, ACp of 2.5 kcal/mol-deg. 

Essentially the characteristic temperature is a measure of the temperature at which the atomic heat capacity is changing from zero to 6 cal deg for silver (0 = 215 K) this occurs around 100 K, but for diamond (0 = 1860 K) with a much more rigid structure, the atomic heat capacity does not reach 5 cal deg i until 900 K. Those elements that resist compression and that have high melting points have high characteristic temperatures. Equations have been derived relating y/ u ) to the characteristic temperature 0. At room temperature diamond, with a characteristic temperature of 1860 K, has a root-mean-square amplitude of vibration, / u ) of 0.02 A, while copper and lead, with characteristic temperatures of 320 and 88 K, respectively, have values of 0.14 and 0.28 A for (u ). - Similar types of values are obtained for crystals with mixed atom (or ion) types. For example, average values of / u ) for Na+ and Cl in sodium chloride (0 = 281 K) are 0.14 A at 86 K and 0.23 A at 290 K. ° ... 

Diethyl sulfide 445 Sodium sulfide nonahydrate (120 g) in water (120 ml) is heated to the boiling point in a distillation flask (750-ml capacity) fitted to a very efficient descending condenser leading to a receiver that is cooled in ice. To this is added diethyl sulfate (155 g) at such a rate that the lively reaction proceeds without external heating. The distillate is saturated with sodium chloride, and the sulfide is separated in a separatory funnel, dried over calcium chloride, and distilled it has b.p. 90-92°, the yield being 78% (35 g). 

For example, Marshall and Slusher (1966) made a detailed evaluation of the solubility of ealeium sulphate in aqueous sodium chloride solution, and suggested that variations in the ion solubility product could be described, for ionic strengths up to around 2 M at temperatures from 0 to 100 °C, by adding another term in an extended Debye Hiickel expression. Above 2 M and below 25 °C, however, further correction factors had to be applied, the abnormal behaviour being attributed to an increase in the complexity of the structure of water under these circumstances. Enthalpies and entropies of solution and specific heat capacity were also reported as functions of ionic strength and temperature. 

The solubilities of the scale-forming salts barium and strontium sulphates in aqueous solutions of sodium chloride have been reviewed by Raju and Atkinson (1988, 1989). Equations were proposed for the prediction of specific heat capacity, enthalpy and entropy of dissolution, etc., for all the species in the solubility equilibrium, and the major thermodynamic quantities and equilibrium constraints expressed as a function of temperature. Activity coefficients were calculated for given temperatures and NaCl concentrations and a computer program was used to predict the solubility of BaS04 up to 300 °C and SrS04 up to 125 °C. 

Ciiss, C. M. and Cobble, J. W., 1961, The thermodynamic properties of high temperature aqueous solutions. I. Standard partial molar heat capacities of sodium chloride and barium chloride from 0 to 100 °C. Jr. Amer. Chem. Soc., 83 3223-8. 

This series of papers contains an extensive array of correlated data on aqueous electrolyte solutions, much of It having been calculated using the system of equations given In paper I In this series. The contents of these papers have been summarized by Pitzer In a chapter in the book edited by Pytkowicz (see Item [123]). The data Include activity and osmotic coefficients, relative apparent molar enthalpies and heat capacities, excess Gibbs energies, entropies, heat capacities, volumes, and some equilibrium constants and enthalpies. Systems of Interest Include both binary solutions and multi-component mixtures. While most of the data pertain to 25 °C, the papers on sodium chloride, calcium chloride, and sodium carbonate cover the data at the temperatures for which experiments have been performed. Also see Items [48], [104], and [124]. 

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