Hexadecane molar volume

Figure 2. Solubility vs. (molar volume of solventY1 for Cu-(RC02)2 salts in hexadecane and octane at 90°C. R groups indicated on curve.

In i vs. 1/V2 should be linear for a fixed solute, and if one assumes that a polyethylene chain is infinite, viz., V = oo, then the value of the intercept at 1/V2 = 0 represents the solubility in polyethylene. Since the concentration of solute is approximately proprotional to < , we have plotted log [solubility (mol/kg)] vs. reciprocal molar volume of octane and hexadecane in Figure 2. The molar volumes of the solvents at 90°C were determined in separate experiments by standard volumetric techniques. 

Since the gel permeation method does not allow a direct determination of the molecular weights or molar volumes of the samples under investigation, calibrations are made by using standard compoimds in the form of a graphic dependence of their molar volume on the elution volume. Normal hydrocarbons (pentane, hexane, heptane, dodecane, hexadecane, octadecane) and aliphatic esters (octyl adipate and octyl sebacate) are used as standards. The molar volumes (ml/mole) were plotted against elution volumes, V (ml) in the calibration curves, as shown in Table 7.19. The molar volumes were calculated from the atomic volumes and structural coefScients. ... 

For many practical purposes, as well as for some theoretical purposes involving statistical thermodynamics, it is expedient to deal with the volume concentration, denoted by c or number density, denoted by p, that is, the number of moles, or molecules of the solute per unit volume of the solution. In dilute solutions the density is usually linear with the concentration, tending to the limiting value of that of the solvent at infinite dilution. There are different numbers of moles of solvent per unit volume in different solvents and at given molarities c or number densities p also per mole of solute. For typical solvents, there are from 55.5 mol for water down to 3.3 mol for hexadecane in 1 dml This constitutes nominally a solvent effect that ought not to be neglected. 

Where SP is a solvation p>arameter related with the free energy change such as gas-liquid partition coefficient, specific retention volume or adjusted retention time at a given temperature. The capital letters represent the solutes properties and the lower case letters the complementary properties of the ionic liquids. The solute descriptors are the excess molar refraction E, dipolarity/ polarizability S, hydrogen bond acidity basicity, A and B, respectively, and the gas-liquid partition coefficient on n-hexadecane at 298 K, L. The solute... 

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