Heat capacity apparent molar

Example 5.1 The apparent molar heat capacities at 298.15 K of HNO3 in aqueous nitric acid solutions are given by the expression5... 

E5.4 The apparent molar heat capacity of sucrose (2) in water (1) is given as a function of the molality, m by the expression... 

The relative apparent molar heat capacity [Pg.365]

Figure 18.6 Thermal properties of aqueous NaCl solutions as a function of temperature, pressure and concentration, (a) activity coefficient (b) osmotic coefficient (c) relative apparent molar enthalpy and (d) apparent molar heat capacity. The effect of pressure is shown as alternating grey and white isobaric surfaces of 7 , , L, and Cp at p = 0.1 or saturation, 20, 30, 40, 50, 70, and 100 MPa, that increase with increasing p in (a), (b), and (d), and decrease with increasing P in (c).

Mixtures of these surfactants with water result in solutions with unique properties that we want to consider. We will use the alkylpyridinium chlorides as examples. Figure 18.11 compares the osmotic coefficient 0, apparent relative molar enthalpy 4>L, apparent molar heat capacity Cp, and apparent molar volumes V as a function of molality for two alkylpyridinium chlorides in water.w19... 

Figure 18.11 (a) Osmotic coefficient (b) apparent relative molar enthalpy (c) apparent molar volume and (d) apparent molar heat capacity, at T = 298.15 K and p = 0.1 MPa, for (1) n-decylpyridinium chloride and (2) n-dodecylpyridinium chloride. 

Figure 18.13 Effect of temperature on (a) apparent relative molar enthalpies (b) apparent molar volumes and (c) apparent molar heat capacities, for n-dodecylpyridinium chloride. The temperatures are (1) 298.15 K (2) 313.15 K and (3) 328.15 K.

The apparent molar heat capacity Cp is obtained from a temperature derivative of equation (18.77) applied to [Pg.347]

Figure 18.15 Surfactant pseudo-phase model prediction for (a) the apparent molar volume and (b) the apparent molar heat capacity. Drawing courtesy of K. Ballerat-Busserolles from the Institut de Chemie des Surfaces et Interfaces, Mulhouse, France.

Figure 18.16 (a) Apparent molar volume and (b) apparent molar heat capacities for aqueous sodium dodecylsulfate at T = 298.15 K and /> = 0.1 MPa, graphed as a function of 1 /m. The insets give the values at low m where a second transition occurs in the micelle. 

Pabalan, R., and Pitzer, K. S. (1988) Apparent Molar Heat Capacity and Other Thermodynamic Properties of Aqueous Potassium Chloride Solutions to High Temperatures and Pressures, J. Chem. Eng. Data 33, 354-362. 

By plotting the observed values of the apparent molar heat capacity against the molality, it is possible to determine d4>c/dm at any molality, and hence Cp2 at that molality can be obtained from equation (44.49). This procedure is satisfactory for nonelectrolytes, but for electrolytes it is preferable to plot 0c as a function of as in 44f thus, equation (44.49) may be writt ... 

Since the value of the apparent molar heat capacity at infinite dilution may be obtained by the extrapolation of experimental data, it is thus possible, as indicated earlier, to determine Cp2 the partial molar heat capacity of the solute at infinite dilution. 

From this result, it is possible to obtain, by means of an equation of the form of (42.7), an expression for the apparent molar heat capacity thus. 

A. Blume, Biochemistry, 22, 5436 (1983). Apparent Molar Heat Capacities of Phospholipids... 

After this review was completed, results from an extensive experimental study (from 278.15 to 393.15 K at 0.35 MPa) were reported [2004BRO/MER] for aqueous Ni(N03)2 solutions. The new apparent molar heat capacity values are markedly more negative than those reported by Spitzer et at. [79SPI/OLO]. 

Drakin, Madanat and Karlina [85DRA/MAD] reported measurements of the apparent molar heat capacities for nickel sulphate solutions at 50°C, 70°C and 90°C. The data are too sparse to be used to estimate the partial molar heat capacity of the ion pair. 

Apparent molar heat capacities were determined for nickel sulphate solutions at 50, 70 and 90°C. The lowest molalities used were 0.3 mol kg, and the extrapolation to / = 0 is problematic, especially if a model that invokes association between nickel and sulphate ions is to be used. The values from this study are not used in the present assessment. 

This is probably the most comprehensive set of heat capacity results available for any nickel salt in aqueous solution. Apparent molar heat capacities of aqueous Ni(C104)2 were measured calorimetrically from 25 to 85°C over a molality range of 0.02 to 0.80 moFkg. Standard molar heat capacities of Ni for the same temperature range were obtained by using the additivity rule and data for HC104(aq), given in literature. The results for C° (Ni " ) can be fitted with a conventional heat capacity model valid from... 

PAT/WOO] Patterson, B. A., Woolley, E. M., Thermodynamics of ionization of water at temperatures 278.15 K < T/K < 393.15 K and at the pressure p = 0.35 MPa apparent molar volumes and apparent molar heat capacities of aqueous of potassium and sodium nitrates and nitric acid, J. Chem. Thermodyn., 34, (2002), 535-556. Cited on pages 87, 88. 

Tremaine, P.R., Sway, K., and Barbero, J.A., 1986, The apparent molar heat capacity of aqueous hydrochloric acid from 10 to 40°C Jour. Solution Chem., v. 15, pp. 1-22. 

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