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Solutions
Published in W. John Rankin, Chemical Thermodynamics, 2019
The solution illustrated in Figure 9.6(a) is an ideal solution. In an ideal solution, the partial pressure of each component is directly proportional to its concentration. This is known as Raoult’s law which can be stated more precisely as follows: The partial pressure of each component of an ideal solution is equal to the product of the vapour pressure of the pure component and its mole fraction in the solution, that is,
Preformulation
Published in Sandeep Nema, John D. Ludwig, Parenteral Medications, 2019
N. Murti Vemuri, Abira Pyne Ramakrishnan
Osmolality is a colligative property. Colligative properties of solutions are properties that depend upon the concentration of undissociated solute molecules and/or ions but not upon the identity of the solute. This ideal solution behavior assumes no specific interactions (e.g., hydrogen bonding) between solute and solvent molecules. Since many solutions are nonideal, or “real solutions,” (resulting from solute–solute and solute–solvent interactions such as dimerization or hydrogen bonding), a direct measurement of properties can give us this measure. Measurable colligative properties include vapor pressure lowering, boiling point elevation, freezing point depression, and osmotic pressure.
Paraffin wax
Published in Jon Steinar Gudmundsson, Flow Assurance Solids in Oil and Gas Production, 2017
The fugacity of the vapour phase is referenced to an ideal gas and the fugacity of the liquid phase is referenced to an ideal solution. In an ideal gas, the molecules themselves occupy no volume and have no intermolecular interactions. Gases at low pressure, approximate this behaviour. In an ideal solution, the molecules exhibit the same intermolecular interaction between all the components/constituents. Components having similar molecular structure, approximate this behaviour.
Polyethylene glycol and membrane processes applied to suction control in geotechnical osmotic testing
Published in International Journal of Geotechnical Engineering, 2022
Rick Vandoorne, Petrus J. Gräbe, Gerhard Heymann
An ideal solution is one in which the volume change of mixing and change in enthalpy during mixing are zero (Rudin 1999). In an ideal solution solute–solute, solvent–solvent and solute–solvent interactions are indistinguishable from one another, obeying Raoult’s law. Thus, ideality is generally approached for very dilute solutions and for solutions where the solvent and solute molecules are of a similar size and nature (Brown et al. 2018). For solutions of PEG as are relevant to this paper, Equation 2 deviates rapidly from reality as the concentration increases (Flory 1953; Manohar 1966; Money 1989). PEG molecules are much larger than water molecules and form strong hydrogen bonds in aqueous solution (Eliassi, Modarress, and Mansoori 1998). This compromises the assumptions of Raoult’s law. The presence of hydrogen bonds lowers the water activity more than would be calculated by Equation 2. Therefore, application of Van’t Hoff’s (1887) equation to determine the osmotic pressure of aqueous PEG will result in gross errors.