What is Ideal Mixtures

Ideal mixing properties can be recognized in the formation of an ideal gas mixture from ideal gases.

Consider the formation of a mixture of gases i.e. a gaseous solution, from two mixtures of pure gases. A useful characterization of an ideal mixture, or solution, can be obtained by beginning with Dalton's law of partial pressures. That law, as seen in the pressure needed to confine a mixture of gases to a container is equal to the sum of the pressures that would be needed to confine the gas components separately to the same container.

The formation of Dalton's law binary mixture can be pictured by the process suggested in the fig. we begin with the gas sample containing of the separate components, each at pressure P. the mixing process consists of the expansion of each component to fill the entire container.

Suppose there are two containers nA mol of A and nB mol of B. the gas sample, both before and after mixing, has a volume V, and pressure to confine the gas to this volume is P. before mixing, the components are both occupy the total volume, and the pressures, or partial pressures, needed to confine them are also proportion to the number of moles. The relations that are implied are shown in fig.

The exponent of each component in this ideal gas mixture process occurs without regard to the presence of the other component. The change that occurs in the mixing is the sum of the changes experienced by each component.

From the relation between free energy and pressure for an ideal gas so that we have:

GA (in mixture) - GA (pure) = nRT in xB

G(in mixture) - GB (pure) = nRT in xB  

Ideal solutions: the free energy result of the above equation was developed by piecing together features of ideal behavior. In a more elegant procedure, adherence to the equation and to the consequences of this equation is used as the definition of ideal solution behavior. The entropy and free energy changes for the formation of 1 mol of an ideal gas solution are shown in the fig. and along with enthalpy it is accurate. Gas mixtures, except a high pressures or low temperatures, confirm to these ideal mixture characteristics. In what follows we treat gas mixtures as ideal.

Liquid mixtures, i.e. solutions, generally do not; behave according to these ideal mixing expressions. The volume of the solution is not always equal to the sum of the volume of the separate components. In the formation of a solution energy must often be exchanged with the thermal surroundings to maintain a constant temperature. Only for a few solutions are the free energy and entropy changes given by the ideal solution expressions. 

Entropy and free energy change at 25°C for formation of 1 mol of an ideal binary solution:

Mole fraction (xA) Mole fraction (xB) xA R In xA, Jk-1mol-1 xB R In xB, Jk-1mol-1 ΔSmix, JK-1mol-1 T ΔSmix, J mol-1 ΔGmix, J mol-1
1 0 0 0 0 0 -0
0.9 0.1 -0.79 -1.91 2.70 805 -805
0.8 0.2 -1.48 -2.68 4.16 1240 -1240
0.7 0.3 -2.08 -3.00 5.08 1510 -1510
0.6 0.4 -2.55 -3.05 5.60 1670 -1670
0.5 0.5 -2.88 -2.88 5.76 1720 -1720
0.4 0.6 -3.05 -2.55 5.60 1670 -1670
0.3 0.7 -3.00 -2.08 5.08 1510 -1510
0.2 0.8 -2.68 -1.48 4.16 1240 -1240
0.1 0.9 -1.91 -0.79 2.70 805 -805
0 0 0 0 0 0 -0

   Related Questions in Chemistry

  • Q : What is synthetic rubber and how it

    To meet human needs, scientists have started preparing synthetic rubbers. Besides having similar properties as natural rubbers they are tougher, more flexible and more durable than natural rubber. They are capable of getting stretched to twice its length. Though, it reverts to its original shape

  • Q : Vapour pressure of water Give me answer

    Give me answer of this question. 5cm3 of acetone is added to 100cm3 of water, the vapour pressure of water over the solution: (a) It will be equal to the vapour pressure of pure water (b) It will be less than the vapour pressure of pure water

  • Q : Calculating total number of moles

    Choose the right answer from following. While 90 gm of water is mixed with 300 gm of acetic acid. The total number of moles will be: (a)5 (b)10 (c)15 (d)20

  • Q : Problem on equilibrium constant Ethanol

    Ethanol is manufactured from carbon monoxide and hydrogen at 600 K and 20 bars according to the reaction2 C0(g) + 4 H2(g) ↔ C2H5OH(g) + H2O (g)The feed stream contains 60 mol% H2, 20 m

  • Q : What are different mechanisms for

    Nucleophilic substitution reactions in halides containing  - X bond may take place through either of the two different mechanisms,S<

  • Q : What is Flash Photolysis Reactions.

    An example illustrates the type of mechanism that can be written to explain the development of flash photolysis reactions. Often, as the reactions in the ozone layer of the earth's atmosphere, we are interested in the kinetic behavior of species that are not a

  • Q : Define alum Illustrate alum?

    Illustrate alum?

  • Q : Analytical chemistry 37% weight of HCl

    37% weight of HCl and density is 1.1g/ml. find molarity of HCl

  • Q : What is schrodinger wave equation? The

    The Schrodinger wave equation generalizes the fitting-in-of-waves procedure.The waves that "fit" into the region to which the particle is contained can be recognized "by inspection" only for a few simple systems. For other problem a mathematical procedure

  • Q : What is protein in Chemistry Illustrate

    Illustrate what is protein in Chemistry?

©TutorsGlobe All rights reserved 2022-2023.