solution

solution

1. a homogeneous mixture of two or more substances in which the molecules or atoms of the substances are completely dispersed. The constituents can be solids, liquids, or gases

2. the act or process of forming a solution

3. the state of being dissolved (esp in the phrase in solution)

4. a mixture of two or more substances in which one or more components are present as small particles with colloidal dimension; colloid

5. Maths

a. the unique set of values that yield a true statement when substituted for the variables in an equation

b. a member of a set of assignments of values to variables under which a given statement is satisfied; a member of a solution set

6. the stage of a disease, following a crisis, resulting in its termination

7. Law the payment, discharge, or satisfaction of a claim, debt, etc.

Collins Discovery Encyclopedia, 1st edition © HarperCollins Publishers 2005

solution

[sə′lü·shən]

(chemistry)

A single, homogeneous liquid, solid, or gas phase that is a mixture in which the components (liquid, gas, solid, or combinations thereof) are uniformly distributed throughout the mixture.

McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.

solution

(jargon)

A marketroid term for something he wants to sell you without bothering you with the often dizzying distinctions between hardware, software, services, applications, file formats, companies, brand names and operating systems.

"Flash is a perfect image-streaming solution." "What is it?" "Um... about a thousand dollars."

See also: technology.

This article is provided by FOLDOC - Free Online Dictionary of Computing (foldoc.org)

solutions

Cataloging a vendor's hardware and software offerings by industry or application. "Solutions" has become such a marketing buzzword that many vendors tout only solutions on their websites, having eliminated reference to their products and services. In such cases, if the prospective customer's problem is not addressed by one of the vendor's solutions for an industry, it can be very unclear what the vendor's products actually do without further investigation. See solutions architect and solutions provider.

Copyright © 1981-2025 by The Computer Language Company Inc. All Rights reserved. THIS DEFINITION IS FOR PERSONAL USE ONLY. All other reproduction is strictly prohibited without permission from the publisher.

The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.

Solution

 

a macroscopically homogeneous mixture of two or more substances, or components, that form systems in thermodynamic equilibrium. All the components of a solution exist in a molecularly dispersed state and are uniformly distributed as separate atoms, molecules, or ions or as groups of a relatively small number of the above-mentioned particles. From a thermodynamic viewpoint, solutions are phases of variable composition in which the ratio of the components may vary continuously within certain limits under given external conditions. Solutions may be gaseous or solid, but term “solution” most frequently refers to a liquid solution.

Practically all liquids encountered in nature are solutions. For example, seawater is a solution of a large number of inorganic and organic substances in water, and petroleum is a solution of many components, which are usually organic. Solutions are found widely in industry and daily life.

The simplest components of solutions usually may be separated in pure form, and a solution of permissible composition can be formed by remixing such components. The quantitative ratio of components is determined by their concentrations. The major component is usually called the solvent, and the other components are called solutes. If one of the components is a liquid and the others are gases or solids, the liquid is considered to be the solvent.

The classification of solutions is based on various criteria. Thus, a distinction based on the concentration of the solute is made between concentrated and dilute solutions. The nature of the solvent determines whether a solution is aqueous or nonaqueous (alcoholic and ammonia solutions). Based on the concentration of hydrogen ions, a distinction is made between acid, neutral, and basic solutions.

In accordance with their thermodynamic properties, solutions are divided into certain classes, primarily into ideal and nonideal solutions. In ideal solutions the chemical potential μ_i, of each component i has a simple logarithmic dependence on its concentration (for example, on the mole fraction x_i):

(1) where is the chemical potential of the pure component, which is dependent only on the pressure P and the temperature T, and where R is the gas constant.

For ideal solutions, the enthalpy of mixing of the components is equal to zero, and the entropy of mixing is given by the same formula as for ideal gases. The change in volume upon mixing the components is equal to zero. These three properties of an ideal solution fully characterize it and may be considered as criteria for ideal solutions. Both Raoult’s laws and Henry’s law are satisfied for ideal solutions. It has been found that solutions are ideal only if their components are similar to each other, primarily in regard to geometric configuration and molecular size. Solutions most similar to ideal solutions are mixtures of identical compounds containing different isotopes of the same element.

As a rule, equation (1) holds for ideal solutions in areas of concentration change. The concentrations at which marked deviations from the ideal are first observed in a given solution depend very strongly on the nature of the solution components. Most sufficiently dilute solutions behave as ideal solutions.

Solutions not having the properties of ideal solutions are called nonideal. For these solutions, the relation that holds is analogous to equation (1), but the concentration is replaced by the activity a_i = γ_ix_i where a_i is the activity of component i and γ_i, is the activity coefficient, which depends both on the concentration of the given component and of the other components and on the pressure and temperature.

Regular solutions form a large class of nonideal solutions. They are characterized by the same entropy of mixing as ideal solutions, but their enthalpy of mixing is nonzero and proportional to the logarithms of the activity coefficients. Athermic solutions form a special class in which the heat of mixing is equal to zero; the activity coefficients are determined only by the entropy term and are independent of the temperature. The theory of such solutions frequently permits the prediction of the properties of nonideal solutions, for example, in the case of nonpolar components with very different molecular volumes. Many solutions of high molecular weight compounds in ordinary solvents are similar to athermic solutions.

At a given temperature and pressure, the dissolution of one component in another usually involves, within some limits, a change in concentration. Solutions in equilibrium with one of the pure components are called saturated solutions, and the concentrations of such solutions are the solubility of the component. The dependence of the solubility on temperature and pressure is represented graphically by a solubility diagram. At concentrations below the solubility of the solute, a solution is unsaturated. If a solution does not contain crystallization nuclei, it may be cooled so that the concentration of the solute becomes greater than the solubility and the solution becomes supersaturated. A series of solution properties of practical importance is related to the change in the pressure of the saturated vapor of the solvent above a solution upon changing the concentration of the solute. Such properties include a lowering of the freezing point and an increase in the boiling point.

The structure of a solution is primarily determined by its components. If the components are similar in chemical structure and molecular size, the structure of the solution, in principle, will not differ from the structure of the pure liquids. Compounds that markedly differ in molecular structure and properties usually interact strongly with each other, leading to the formation of complexes in the solution that cause deviation from the ideal. The energy of formation of these complexes may reach several kJ/mole, indicating the presence of weak chemical interactions in the solution and the formation of some chemical compounds as new components of the solution. The interaction with solvent molecules for many compounds (for example, electrolytes) is accompanied by the opposite phenomenon, namely, dissociation. Upon dissolution in water, salts, acids, and bases partially or completely dissociate into ions, resulting in an increase in the number of different particles in the solution. Dissociation also characterizes other polar solvents. In electrolytic dissociation, the overall electrical neutrality is retained, and a layer of closely related solvent molecules (the solvation shell) forms around each ion. The structure of the solvent is retained in solutions at very low concentrations of the solute. As the concentration of the solute increases, new structures arise. For example, various crystalline hydrate structures arise in aqueous solutions. Large ions destroy the structure of the solvent, resulting in experimentally observed structural nonuniformities. Solutions of macromolecular compounds are characterized by specific features.

The statistical molecular theory of solutions has been developed only for the simplest classes of solutions. Thus, in considering the solutions of nonassociated liquids, the concept of solutions as statistical sets of solids (“spheres,” “ellipsoids,” and “rods”) that interact with each other according to a defined model law is used. For highly dilute solutions of electrolytes, the consideration is limited to only the electrostatic interaction of the ions as point charges or as spheres of a given radius.

REFERENCES

Kirillin, V. A., and A. E. Sheindlin. Termodinamika rastvorov. Moscow, 1956.
Shakhparonov, M. I. Vvedenle v molekuliarnuiu teoriiu rastvorov. Moscow, 1956.
Prigogine, I. The Molecular Theory of Solutions. Amsterdam, 1957.
Robinson, R., and R. Stokes. Rastvory elektrolitov. Moscow, 1963. (Translated from English).
Tager, A. A. Fiziko-khimiiapolimerov, 2nd ed. Moscow, 1968.
Kurs fizicheskoi khimii, 2nd ed., vols. 1–2. Edited by Ia. I. Gerasimov. Moscow, 1969–73.

N. F. STEPANOV

The Great Soviet Encyclopedia, 3rd Edition (1970-1979). © 2010 The Gale Group, Inc. All rights reserved.