Density of solutions

Density of solution and solvent were measurement with Anton Paar densimeter DMA5N. For determining the hydration value is used the following concentrations of gelatin in aqueous solution 0.2, 0.4, 0.5 and 0.6%. 

Notice that if we assign number densities of solute molecules, pa( n), in conformation n, according to... 

The interconversion between molal and molar expressions can be done if the density of solution at 25°C is known. The density should be that of the solution at the freezing point. The grams of solute per milliliter should also be measured at 25°C. The relation can be expressed as ... 

Surface tension and interfacial tension (n-heptane/H O) were determined by the drop-volume method (11). The density of solutions for calculating surface and interfacial tension were measured with a U-tube pycnometer. 

A chart giving a detailed relation between relative vapor pressures, %H2SC>4 and density of solutions is given on p 328 of Ref 1... 

TABLE OP TnE DENSITY OF SOLUTIONS OF SIIOAB, AOOOSDIYO TO EEAUMi. 

The densities of solutions of various concentrations at 17° C. have been determined as follows 8... 

Here M is molecular weight, R is the gas constant, T is the absolute temperature in degrees Kelvin, V is the partial specific volume of the solute, p is the density of solution, w is the angular velocity, r is the distance from the center of rotation, and c is the concentration measured at r. Under... 

As before, the density of solute in any streamline rapidly becomes uniform across the tube, the relaxation time being of the order of Af1, where A, is the smallest of the eigenvalues. 

The densities of sea water, normal, diluted, and concentrated, and of aqueous solutions of ammonium bicarbonate are given as a function of concentration in Figure 5. Figure 6 gives the densities of solutions of ammonium bicarbonate made up in sea water of varying salinity. All of these density measurements were made at 20° C. by means of a pycnometer. 

The table used for the calculation of the extract is based on the density of aqueous saccharose solutions, so that the extract thus calculated has only a conventional value. Other tables exist which are based on the densities of solutions of grape must, but in view of the varying proportions in which the components of the must occur in the extracts of wines of different types, such tables also have mo more than a conventional value. 

The most common protein precipitation technique involves the use of ammonium sulphate, which has been the subject of a recent review (3). The widespread use of ammonium sulfate can be ascribed to the fact that it is very soluble (saturated solutions have a concentration in the region of AM), the density of solutions do not compromise collection of precipitates by centrifugation and its use does not promote denaturation of proteins. The addition of ammonium sulfate will cause a neutralization of the surface charge of the protein and a decrease in the effective concentration of water leading to a decrease in protein solvent interactions. 

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