6.03 Calorimetry

In order to describe the molar volume of pure water the equation V_3=M_3⁄ρ_(3 ) is used, whereas those of sodium nitrate and the polyether compound poly(ethylene glycol) (PEG) are shown by V_1=V_(∅_1)^∞and V_1=V_(∅_2)^∞. In these two equations, V_(∅_1)^∞ and V_(∅_2)^∞ which are the apparent molar volumes at infinite dilution of sodium nitrate and poly(ethylene glycol), must be computed on the basis of data on apparent molal volume (V_∅). The following equation shows the relation of the V_∅ of a binary solution with density,
Equation 1
The notations which are used in Equation 1 are as follows: mi: Molality of solute i,
F: Density of the binary solution, ρ_w: Density of water.

In general,
In order to yield apparent molal volumes at infinite dilutionV_∅^∞, the apparent molar volumes V_∅ of aqueous electrolyte solutions are extrapolated to zero concentration employing the Conway et al. [11, 16] equation:
Equation 2
To obtain the values for V_∅^∞ given in Table 6, they were fitted to equation 7. Note that prior measurements of density on poly(ethylene glycol) + water should perform to calculate the values of V_∅^∞ for the polymer. Table 3 has shown these empirical values for different molalities of poly(ethylene glycol). Some of the researchers 11, 18, 20 have proposed that the dependency of〖 V〗_∅ on the molality of the polymer is a linear function specified