Nama/NIM: Muhamad Syaiful Ampri/Kelompok: Kimia () Judul: “ HUKUM RAOULT” ALAT dan BAHAN. Contoh campuran ideal. Campuran ideal dan perubahan entalpi pada proses pencampuran. Hukum Raoult Tekanan uap / diagram komposisi. Raoult’s law (Q) François-Marie Raoult hywiki Ռաուլի օրենքներ; idwiki Hukum Raoult; itwiki Legge di Raoult; jawiki ラウールの法則; jvwiki Hukum .

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If all these hikum are the same, there won’t be any heat either evolved or absorbed. Raoult’s Law may be adapted to non-ideal solutions by incorporating two factors that account for the interactions between molecules of different substances. Suppose you double the mole fraction of A in the mixture keeping the temperature constant. The aroult can be replaced by simple pressures if the vapor of the solution behaves ideally i. If you have a second liquid, the same thing is true.

Real fractionating columns whether in the lab or in industry automate this condensing and reboiling process.

You can see that we now have a vapor which is getting quite close to being pure B. If a liquid has a high vapor pressure at some temperature, raoulh won’t have to increase the temperature very much until the vapor pressure reaches the external pressure.

For the purposes of this topic, getting close to ideal is good enough!

You can easily find the partial vapor pressures using Raoult’s Law – assuming that a mixture of methanol and ethanol is ideal. Raoult’s Law The partial vapor pressure of raoulh component in a mixture is equal to the vapor pressure of the pure component at that temperature multiplied by its mole fraction in the mixture. The solute also shows a linear limiting law, but with a different coefficient.

These are mixtures of two very closely similar substances. If the deviation is large, then the vapor pressure curve shows a maximum at a particular composition and form a positive azeotrope.

This modified or extended Raoult’s law is then written: This is obvious the basis for fractional distillation. Retrieved from ” https: That means that there are only half as many of each sort of molecule on the surface as in the pure liquids. The total vapor pressure of the mixture is equal to the sum of the individual partial pressures.


Ideal Mixtures An ideal mixture is one which obeys Raoult’s Law, but I want to look at the characteristics of an ideal mixture before actually stating Raoult’s Law. This phenomenon is the basis for distillation. The more similar the components are, the more their behavior approaches that described by Raoult’s law.

You get the total vapor pressure of the liquid mixture by adding these together. The mole fraction of B falls as A increases so the line will slope down rather than up. Articles related to solutions.

Hukum Raoult

For a solution to be ideal, the interactions between unlike molecules must be hukkm the same magnitude as those between like molecules. This equation shows that, for an ideal solution where each pure component has a different vapor pressure, the gas phase is enriched in the component with the higher pure vapor pressure and the solution is enriched in the component with the lower pure vapor pressure.

In equation form, for a mixture of liquids A huium B, this reads: Raoult’s law is a phenomenological law that assumes ideal behavior based on the simple microscopic assumption that intermolecular forces between unlike molecules are equal to those between similar molecules: Raoullt boil when their vapor pressure becomes equal to the external pressure.

If a non-volatile solute zero vapor pressure, does not evaporate is dissolved into a solvent to form an ideal solution, the vapor pressure of the final solution will be lower than that of the solvent.

Notice again that the vapor is much richer in the more volatile component B than the original daoult mixture was. Views Read Edit View history. If the molecules are escaping easily from the surface, it must mean that the intermolecular forces are relatively weak.

Hukum Raoult dan Destilasi Fraksional by burhan gopur on Prezi

Alembic Kugelrohr Rotary evaporator Spinning band distillation Still. However, doing it like this would be incredibly tedious, and unless you could arrange to produce and condense huge amounts of vapor over the top of the boiling liquid, the amount of B which you would get at the end would be very small.


Assuming also that the vapor mixture acts as an ideal gas, it is then possible to re-derive Raoult’s law as follows. Comparing measured vapor pressures to predicted values from Raoult’s law provides information about the true relative strength of intermolecular forces.

This is why mixtures like hexane and heptane get close to ideal behavior. The beginnings of fractional distillation Suppose that you collected and condensed the vapor over the top of the boiling liquid and reboiled it. You can discover this composition by condensing the vapor and analyzing it.

Many pairs of liquids are present in which there is hukjm uniformity of attractive forces, i. If that is not obvious to you, go back and read the last section again!

Raoult’s law – Wikidata

For example, the system of chloroform CHCl 3 and acetone CH 3 COCH 3 has a negative deviation [5] from Raoult’s law, indicating an attractive interaction between the two components that has been described as a hydrogen bond.

Distillation Physical chemistry Equilibrium chemistry Engineering thermodynamics Solutions. There is actually no such thing as an ideal mixture! An ideal solution would follow Raoult’s Law, but ideal solutions are extremely rare. If you follow the logic of this through, the intermolecular attractions between two red molecules, two blue molecules or a red and a blue molecule must all be exactly the same if the mixture is to be ideal.

Raoult’s law

The presence of these limited linear regimes has been experimentally verified in a great number of cases. Therefore, the vapor pressure is greater than expected from the Raoult’s law, showing positive deviation.

There are two ways of looking at the above question: From Wikimedia Commons, the free media repository. The converse is true for positive deviations. This page deals with Raoult’s Law and how it applies to mixtures of two volatile liquids.