Density of Solvents as a Function

Density of Solvents as a Function of Temperature, 15-25 Density of Sulfuric Acid, 15-40 Density of Various Solids, 15-39 Density, Pressure, and Gravity as a Function of Depth within the Earth,... 

In order to calculate [a , the density of the solutions must be known at each temperature. The density of the solution is close enough to that of the solvent that they can be assumed to be identical. The density of the solvent should be determined with a pycnometer for at least three different temperatures in the range 10 to 50°C. The volume of the pycnometer should first be determined by weighing it empty and also filled with distilled water at a known temperature. Since the density of water as a function of temperature is well known, the volume of the pycnometer can be determined. This procedure (see Exp. 9) is then repeated using the solvent, and since the volume of the pycnometer is now known, the density can be calculated. The solvent density should be plotted against temperature and the best straight line drawn through the points obtained. 

When a solute is added to a solvent, e.g. an electrolyte to water, it might be expected that the final volume of the solution would be greater then the volume of the solvent used. However, this is not always the case, and large negative changes in volume are often found experimentally. These are found by measuring the density of solutions as a function of concentration of the electrolyte. 

Densities of pure solvents are available in handbooks like the Handbook of Chemistry and Physics (Lide 1999). The densities of a number of common solvents appear in Table 1.11. The densities of solutions as a function of concentration are difficult to find except for some common solutes in aqueous solution. The density of NaCl and sucrose as a function of concentration are given in Figure 1.21. 

Figure 19. Density of states as a function of electron energy, (a) Solvent fluctuation model (b) vibronic model.106,107...

The radial distribution of intensity as a function of scattering angle shows features that can be correlated with what is seen at each resolution level of a protein. The first minimum of this function corresponds to intensity data with dhki spacings greater than 6 A. At this resolution the overall shape of the molecule can be assessed, and the boundary between protein and solvent may possibly be seen. At this low resolution, however, the electron density is averaged over a volume greater than that of an individual atom, so that detailed information cannot be obtained. One low-resolution feature is the a helix (see Chapter 12) which appears as a... 

Nitrogen splittings, like 0-splittings, are dependent upon the spin densities at the adjacent atoms, and interpretation of their magnitude is therefore difficult. Nevertheless, the variation of in a series of radicals, as a function of solvent and substituents, can provide information about both intra- and inter-molecular effects. 

Calculate the density profile in an /-arm star polymer in an athermal solvent as a function of the distance from the branch point. How does the size of the polymer depend on the number of arms /, the degree of polymerization N, and monomer size b. 

Figure 1.1-3 The density and the solvent power (as expressed by the Hildebrand parameter) of SCCO2 as a function of temperature and pressure [IS, 16].

---