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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Commonly quoted examples include:. In practice, this is all a lot easier than it looks when you first meet the definition of Raoult’s Law and the equations! If roault system is at equilibriumthen the chemical potential of the component i must be the same in the liquid solution and in the vapor above it. 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: Many pairs of liquids are present in which there is no uniformity of attractive forces, i.

For example, in the next diagram, if you boil a liquid mixture C 1it will boil at a temperature T 1 and the vapor over the top of the boiling liquid will have the composition C 2.

Hukum Raoult

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

If the molecules are escaping easily from the surface, it must mean that the intermolecular forces are relatively weak. For a solution to be ideal, the interactions between unlike molecules must be of the same magnitude as those between like molecules. Retrieved from ” https: Notice that the vapor over the top of the boiling liquid has a composition which is much richer in B – the more volatile component.


You can discover this composition by condensing the vapor and analyzing it. The diagram is used in exactly the same way as it was built up. The system hydrochloric acid – water has a large enough negative deviation to form a minimum in the vapor pressure curve known as a negative azeotropecorresponding to a mixture that evaporates without change of composition.

Thus the total pressure above the solution of A and B would roult. This is called its partial pressure and is independent of the other gases present. Suppose you had a mixture of 2 moles of methanol and 1 mole of ethanol at a particular temperature.

Some mixtures in which this happens are 1 benzene and methanol2 carbon disulfide and acetoneand 3 chloroform and ethanol. You get the total vapor pressure of the liquid mixture by adding these together.

Raoult’s law

The definition below is the one to use if you are talking about mixtures of two volatile liquids. 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. If that is not obvious to you, go back and read the last section again! The net effect of that is to give you a straight line as shown in the next diagram.

Hukum Raoult – Wikipedia

Even if you took all the other gases away, the remaining gas would still be exerting its own partial pressure. Boiling point and Composition Diagrams The relationship between boiling point and vapor pressure If a liquid has a high vapor pressure at huukum particular temperature, it means that its molecules are escaping easily from the surface.

That means that you won’t have to supply so much heat to break them completely and boil the liquid. 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. Suppose you double the mole fraction of A in the mixture keeping the temperature constant.


To get the total vapor pressure of the mixture, you need to add the values for A and B together at each composition. For mixtures of A and B, you might perhaps have expected that their boiling points would form a straight line joining the two points we’ve already got. Raoult’s Law may be adapted to non-ideal solutions by incorporating two factors that account for the interactions between molecules of different substances.

Liquids boil when their vapor pressure becomes equal to the external pressure. This file has been identified as being free of known restrictions under copyright law, including all related and neighboring rights.

It covers cases where the two liquids are entirely miscible in all proportions to give a single liquid – NOT those where one liquid floats on top of the other immiscible liquids.

These are mixtures of two very closely similar substances. That means that an ideal mixture of two liquids will have zero enthalpy change of mixing.

In other words, the partial vapor pressure of A at a particular temperature is proportional to its mole fraction. From Wikipedia, the free encyclopedia. The following other wikis use this file: For example, if the two components differ only in isotopic content, then Raoult’s law is essentially exact.

If you triple the mole taoult, its partial vapor pressure will triple – and so on. This is always negative, so mixing is spontaneous.