Molecular weights of solutes

It follows from what has been said that a is negative. For a molecular weight of solute, we have... 

Calcium-sodium-chloride-type brines (which typically occur in deep-well-injection zones) require sophisticated electrolyte models to calculate their thermodynamic properties. Many parameters for characterizing the partial molal properties of the dissolved constituents in such brines have not been determined. (Molality is a measure of the relative number of solute and solvent particles in a solution and is expressed as the number of gram-molecular weights of solute in 1000 g of solvent.) Precise modeling is limited to relatively low salinities (where many parameters are unnecessary) or to chemically simple systems operating near 25°C. 

Figure 7 Permeation coefficient of solute in HEMA-AEMA copolymer membrane vs. molecular weight of solute. ( ) In the dark (O) under UV irradiation. (From Ref. 28.)...

As will be demonstrated later, LS can be quantified by an experimental quantity termed the excess Rayleigh ratio between solution and solvent, R, which is related to the concentration and molecular weight of solute by the following expression... 

Here, Cv is the heat capacity of solvent at constant volume a (deg-1) is its coefficient of thermal expansion dr (cm2 dyne-1) is the coefficient of isothermal compressibility. From Eq. (49) it is seen that the molecular weight of solute is simply ... 

In a homologous series of compounds, percentage removal increases with molecular weight of solute. 

We may go a step further, however, and introduce an equation of condition for solutions, that is, an equation by which we can calculate the variables of condition of solutions from their composition (specific volumes or concentrations of the components). It is convenient to choose the variable which is easiest to determine experimentally as independent variable. For solutions this is generally their composition or concentration, i.e. the number of mols of solvent or solute in unit volume or in unit mass of the solution. In most cases the concentration can be determined directly by analysis. If c is the number of mols of the solute, and Cq the number of mols of the solvent in unit volume (I litre) of the solution, these two concentrations are connected by the equation Me+Mcq= 1000s where M and are the molecular weights of solute and solvent respectively, and s is the density of the solution. Hence only one of the two quantities c and can be taken as independent variable. 

These two similar-sounding terms must not be confused. The molarity of a solution is the number of moles (gram molecular weights) of solute in 1 litre (1 dm ) of solution. The molality is the number of moles of solute in 1 kg of solvent Molality has the unit, mol kg which... 

Here, the notation MW refers to the molecular weight of solute i and the effective average molecular weights of the extract and raffinate phases, as indicated by the subscripts. For dilute systems, K" IQ (MW a(r ,ai/MWearaa)- Fot theoretical stage or transfer unit calculations, often it is useful to express the partition ratio in terms of mass ratio coordinates introduced by Bancroft [Phys. Rev., 3(1), pp. 21-33 3(2), pp. 114-136 and 3(3), pp. 193-209 (1895)] ... 

Molecular weight of solute probe Site of deposition of labeled solute Recirculation of labeled solute Stability of labeled solute in vivo Ventilation Posture... 

If the mass/volume concentration of solute is C2 and M2 is the molecular weight of solute, then... 

The determination of the molecular weight of solutes by the lowering of vapour pressure could scarcely be regarded as one of the most convenient methods until quite recently, A W C Menzies (Zeitsch fur Phys Chem,1Q, 231, 1911) has described a very convenient form of apparatus in which the lowering of pressure is measured by a column of the solution itself, and which allows accurate determinations of molecular weights being carried out rapidly The following table is an illustration of the accuracy obtainable —... 

These results give some idea ofthe enormous values actually reached in concentrated solutions The curve (Fig 27) shows the osmotic pressure plotted against concentration, so as to show the departure of the P values from the simple linear relation, which holds m dilute solutions The straight line is drawn on the usual assumption that 1 gram molecular weight of solute per liter (solution) should give an osmotic pressure of 22 4 atmospheres... 

By experimentally measuring the turbidity as a function of concentration, one can obtain the molecular weight of solute and the second virial coefficient, B2, which characterizes interactions between solute molecules (or particles). In systems containing charged particles, such as e.g. micelles of ionic surfactants, the second virial coefficient describes the effective charge of particles. The molecular weight and the second virial coefficient can be determined by plotting the quantity Hc/x as a function of concentration, c. 

A = Weight percent of solute B = Molecular weight of solvent E = Molecular weight of solute F = Grams of solute per liter of solution... 

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