Nonelectrolyte, definition

For concentrated solutions, the activity coefficient of an electrolyte is conveniently defined as though it were a nonelectrolyte. This is a practical definition for the description of phase equilibria involving electrolytes. This new activity coefficient f. can be related to the mean ionic activity coefficient by equating expressions for the liquid-phase fugacity written in terms of each of the activity coefficients. For any 1-1 electrolyte, the relation is ... 

Van der Waals forces represent important intermolecular interactions between nonelectrolyte substances, and can be categorized into dipole-dipole, dipole-induced-dipole, and induced-dipole-induced-dipole forces. Polar molecules, by definition, will have a permanent dipole moment, and will interact with the oppositely charged portions or other molecules having permanent dipole moments. The dipole-dipole interaction is known as the orientation effect, or as the Keesom force. 

The phrase concentration of solute particles in the definition of colligative property needs clarification. There are two kinds of solutes, those that exist in solution as neutral molecules and those that ionize when dissolved and exist in solution as ions. Compounds that ionize in water are called electrolytes. Those that do not ionize are nonelectrolytes. Glucose is a nonelectrolyte and exists as neutral molecules in solution. A 1.0 M solution of glucose is 1.0 M in solute particles. Sodium chloride, NaCl, is an electrolyte and exists in solution as separated sodium and chloride ions, NaClfo) — Na+(aq) + CV(aq). A 1.0 M solution of NaCl is 2.0 M in solute particles, 1.0 M Na+(aq) plus 1.0M CV(aq). The concentration of solute particles for compounds that ionize in solution will be some whole number multiple of the concentration of the compound itself. For those solutes that do not ionize when dissolved in water, the concentration of the compound and the concentration of the solute particles (molecules) will be the same. A listing of common nonelectrolytes and electrolytes in water appears in the following table. 

Usually the terms salting in and salting put are used to describe the increase or decrease in solubility that results from the addition of a salt or electrolyte to a solute-solvent system. Their use here to describe the effects of the addition of a nonelectrolyte is. a slight generalization of the definition of these terms. 

In principle, the conventions used for nonelectrolyte solutions developed in Chap. 11 could be employed for electrolyte solutions which are subject to the condition of electroneutrality. Agreement with experimental data could be obtained by choosing the molecular weight to be some fraction of the formula weight. However, these conventions generally lead to activity coefficients which are rapidly varying functions of composition. In order to avoid this, we formally define chemical potentials and activity coefficients for ionic components. The definition of chemical potentials for ionic components does not have operational significance since their concentrations cannot be varied independently. 

Hermida-Ramon JM, Ohrn A, Karlstrdm G (2007) Planar or nonplanar what is the structure of urea in aqueous solutions J Phys Chem B 111 11511-11515 Hildebrand JH, Scott RL (1950) The solubility of nonelectrolytes, 3rd ed. Dover, New York Huyskens PL, Siegel GG (1988) Fundamental questions about entropy. I. Definitions Clausius or Boltzmann Bull Soc Chim Belg 97 809-814... 

In order to calculate the equOibrium composition of a system consisting of one or more phases in equilibrium with an aqueous solution of electrolytes, a review of the basic thermodynamic functions and the conditions of equilibrium is important, This is particularly true inasmuch as the study of aqueous solutions requires consideration of chemical and/or ionic reactions in the aqueous phase as well as a thermodynamic framework which is, for the most part, quite different from those definitions associated with nonelectrolytes. Therefore, in this section we will review the definition of the basic thermodynamic functions, the partial molar quantities, chemical potentials, conditions of equilibrium, activities, activity coefficients, standard states, and composition scales encountered in describing aqueous solutions. 

In principle, everybody knows that an activity coefficient has no significance unless there is a clear definition of the standard state to which it refers. In practice, however, there is all too often a tendency to neglect precise specification of the standard state and in some cases failure to give this exact specification can lead to serious difficulties. This problem is especially important when we consider supercritical components or electrolytes in liquid mixtures and, a little later, I shall have a few comments on that situation. But for now, let us consider mixtures of typical nonelectrolyte liquids at a temperature where every component can exist as a pure liquid. In that event, the standard-state fugacity is the fugacity of the pure liquid at system temperature and pressure and that fugacity is determined primarily by the pure liquid s vapor pressure. 

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