Regular solution

Regular solution

A regular solution is a solution that diverges from the behavior of an ideal solution only moderately [Simon & McQuarrie Physical Chemistry: A molecular approach] .

More precisely it can be described by Raoult's law modified with a Margules function with only one parameter α:

: P1= x1P*1f1,M: P2= x2P*2f2,M

Where the Margules function is

:f1,M = exp(αx22):f2,M = exp(αx12)

Notice that the Margules function always contains the opposite mole fraction. It can also be shown that if the first Margules expression hold that the other one must have the same shape using the Gibbs-Duhem relation.

The value of α can be interpreted as W/RT, where W = 2U12-U11-U22

represents the difference interaction between like and unlike neighbors.

In contrast to the case of ideal solutions, regular solutions do possess an enthalpy of mixing, due to the W term. If the unlike interactions are more infavorable than the like ones, we get competition between an entropy of mixing term that produces a minimum in the Gibbs free energy at x=0.5 and the enthalpy term that has a maximum there. At high temperatures the entropy wins and the system is fully miscible, at lower temperatures the G curve will have two minima and a maximum in between. This results in phase separation. In general there will be a temperature where the three extremes coalesce and the system becomes fully miscible. This point is known as the critical point of solubility or the consolute point.

In contrast to ideal solutions, the volumes in the case of regular solutions are no longer strictly additive but must be calculated from the partial molar volumes that are a function of x.


Wikimedia Foundation. 2010.

Игры ⚽ Поможем написать реферат

Look at other dictionaries:

  • regular solution — reguliarusis tirpalas statusas T sritis chemija apibrėžtis Tirpalas, kurio tirpinio ir tirpiklio molekulės išsidėsčiusios chaotiškai ir nesudaro asociatų. atitikmenys: angl. regular solution rus. регулярный раствор …   Chemijos terminų aiškinamasis žodynas

  • Regular singular point — In mathematics, in the theory of ordinary differential equations in the complex plane , the points of are classified into ordinary points, at which the equation s coefficients are analytic functions, and singular points, at which some coefficient …   Wikipedia

  • Regular Show — title card …   Wikipedia

  • regular conjugation — Weak Weak (w[=e]k), a. [Compar. {Weaker} (w[=e]k [ e]r); superl. {Weakest}.] [OE. weik, Icel. veikr; akin to Sw. vek, Dan. veg soft, flexible, pliant, AS. w[=a]c weak, soft, pliant, D. week, G. weich, OHG. weih; all from the verb seen in Icel. v[ …   The Collaborative International Dictionary of English

  • Ideal solution — In chemistry, an ideal solution or ideal mixture is a solution in which the enthalpy of solution is zero; [ A to Z of Thermodynamics Pierre Perrot ISBN 0198565569] the closer to zero the enthalpy of solution, the more ideal the behavior of the… …   Wikipedia

  • Frobenius solution to the hypergeometric equation — In the following we solve the second order differential equation called the hypergeometric differential equation using Frobenius method, named after Ferdinand Georg Frobenius. This is a method that uses the series solution for a differential… …   Wikipedia

  • Metal ions in aqueous solution — A metal ion in aqueous solution is a cation, dissolved in water, of chemical formula [M(H2O)n]z+. The solvation number, n, determined by a variety of experimental methods is 4 for Li+ and Be2+ and 6 for elements in rows 3 and 4 of the periodic… …   Wikipedia

  • MUSE QoS solution — MUSE advocates the introduction of QoS into IP networks as this allows better resource utilization while at the same time it allows to serve multiple and different applications with the transport quality they actually need.The solution needs to… …   Wikipedia

  • 3V (payment solution) — For the courier company formerly known as 3V, visit TNT N.V. 3V is a payment solution marketed by Permanent TSB and Alphyra and is running in Ireland, Germany, Spain and in the United Kingdom. The system allows anybody over 16 years of age to… …   Wikipedia

  • Gowdy solution — Gowdy universes or, alternatively, Gowdy solutions of Einstein s equations are simple model spacetimes in general relativity which represent an expanding universe filled with a regular pattern of gravitational waves.External links*Citation first1 …   Wikipedia

Share the article and excerpts

Direct link
Do a right-click on the link above
and select “Copy Link”