Specific volume of solvents

In chemistry, solutions are prepared so that a specific concentration of particles, the solute, is added to a specific volume of solvent. When a uniform mixture of solute and solvent results, a solution is formed. The concentration of a solution is expressed as the ratio of solute to solution, solution being solute plus solvent. In the next demonstration, we examine a change in value through dilution using mass percent as a means of expressing concentration of the solution. In mass percent, the ratio of grams of solute to grams of solution, multiplied by 100, is used to calculate the mass percent of the solution. 

M2 are molar mass of solvent and solute a g are the second and third vlrial coefficients and V] (t V2 are the partial specific volume of solvent and solute... 

Pi, K volume and mass fraction of the volatile component P°vO>PvO vapor pressure above pure solvent and polymeric solution Vi,Vj specific volumes of solvent and polymer... 

Using the relationship between solvent chemical potential and the specific volume of solvent (i.e., of a lattice site), Hv = -A U yields... 

V[, v specific volumes of solvent and polymer X parameter of thermodynamic interaction... 

The specifications set the maximum vol % of solvent that may be added to the cylinder shell (measured by its water capacity). The volume of solvent also varies with the capacity of the cylinder. Cylinders in the 90—92% porosity range with a capacity above 9.1 kg of water may contain a maximum acetone charge of 43.4%, whereas those with 9.1 kg or less water capacity may contain up to 41.8 vol %. The first category of cylinders are normally referred to as welding cylinders and the latter as small tanks (those with 0.28 and 1.12 m acetylene capacity). 

The viscosity increment was determined as v = B v = 172.7 ( 2 5 for spheres) where B is the viscosity coefficient characteristic of a given solue-solvent pair, and amounts to (9.91 0.24)xl0" ff/ A g" for PGA in aqueous solution. is the partial specific volume of the macromolecular component equal to [Pg.612]

Systems have been developed by some of the major spectrometer manufacturers to deal specifically with this type of application. These systems are designed with automation very much a priority. Typically, an integrated robot adds a predetermined volume of solvent to each of the wells and then injects the resultant solution into a flow line that transfers it into the spectrometer s probe, which is of course fitted with a flow cell. Spectroscopy can then be performed without the time constraints of the HPLC-NMR system and the sample returned to the well on the plate where it came from, or into a fresh one if required. 

A plot of column effluent composihon as a function of time or volume of solvent and feed reveals the adsorption and desorphon behaviors of the components in the feed mixture and illustrates whether the adsorphon system is suitable for separating the components. Particularly important is the sequence and hme when each of the feed components exit the packed adsorbent column because these characteristics describe the specific adsorbate and adsorbent interactions. From... 

Percent recovery is the percent of the chemical collected under actual sampling conditions which is recovered for analysis. The major contributing factor to low recovery is often the desorption efficiency, i.e., the partitioning of a chemical, at equilibrium, between a specific kind and volume of solvent and a specific batch and amount of solid sorbent. Recovery and desorption efficiency are not always... 

Volume Displacement. This parameter is not a factor in dissolution testing but can prove to be a very important factor in automated assay, content uniformity, or degradation and impurities testing. It specifically addresses the volume displaced by the tablets in solution. Since manual sample preparations are often prepared utilizing volumetric flasks where the solution is diluted to the mark, the actual volume of solvent added to the flask is irrelevant. However, this actual volume... 

Here Vi and v are the partial specific volumes of the polymer (/ = 2,4) and the solvent, respectively M is the molar weight of the solvent and Xu and 724 are the Flory-Huggins interaction parameters, quantifying the energy of interaction between unlike lattice-based polymer segments (%24) or between polymer segments and solvent molecules (%u). 

In equation (5.37), v/ is the partial specific volume of the biopolymer and ps is the solvent density. Making use of the relationship between the thermodynamic activity of the biopolymer in solution and its osmotic second virial coefficient (see chapter 3 for more details), one can get the following relationship (Deszczynski et al., 2006) ... 

---