Raoult, Francois

Rankine William John Macquorn (1 820-1872) Scot, phys., researched thermodynamic theory of steam, engine performance, water waves Raoult Francois Marie (1830-1901) Fr. phys., developed (Raoult s) Law for vapor pressure of solvent in solution being proportional to the number ratio of solvent/solute molecules, demonstrated depression of freezing points proportionally to concentration of dissolved substances Rayleigh see Strutt... 

Raoult, Francois-Marie (1830-1901) A French chemist who studied the behaviour of solutions and their physical properties. He is best known for his work on solutions, in particular the depression of freezing points and the depression of a solvent s vapour pressure due to a solute that was shown to be proportional to the solute s molecular weight. Both became ways of determining molecular weights of organic substances. "Raoult s law is named after him. 

In this equation, Pt is the vapor pressure of solvent over the solution, P° is the vapor pressure of the pure solvent at the same temperature, and Xj is the mole fraction of solvent. Note that because Xj in a solution must be less than 1, P must be less than P°. This relationship is called Raoult s law Francois Raoult (1830-1901) carried out a large number of careful experiments on vapor pressures and freezing point lowering. 

More than 80 years later Francois Raoult demonstrated that at low concentrations of a solute, the vapour pressure of the solvent is simply... 

The French scientist Francois-Marie Raoult spent much of his life measuring vapor pressures and discovered that the vapor pressure of a solvent is proportional to its mole fraction in a solution. This statement, which is called Raoult s law, is normally written... 

Francois Marie Raoult studied colligative properties in the 1870s. He developed Raoult s Law relating solute and solvent mole fraction to vapor pressure lowering. 

One of the first to investigate the mathematical relationship between the vapor pressure reduction and the amount of solute was Francois Raoult. The mathematical relationship he determined is known as Raoult s law. What the law states is that the partial pressure of the solvent over a solution equals the vapor pressure of the pure solvent times the mole fraction of solvent in the solution. As Equation 10.4, this becomes... 

You have learned that adding a nonvolatile solute to a solvent lowers the vapor pressure of that solvent. The amount by which the vapor pressure is lowered can be calculated by means of a relationship discovered by the French chemist Francois Marie Raoult (1830-1901) in 1886. According to Raoult s law, the vapor pressure of a solvent (P) is equal to the product of its vapor pressure when pure (P°) and its mole fraction (X) in the solution, or... 

This equation expresses RaoulVs f law. According to Eq. (10.4), the left-ha t Francois Marie Raoult (1830-1901), French chemist. 

In 1886 the French chemist Francois Marie Raoult 1830-1907 reported extensive vapor-pressure results on solutions, and found them to agree very satisfactorily with this equation. Solutions that obey this law are said to be ideal For solutions that do not, the mole fraction is corrected by multiplying it by an activity coefficient. 

A Frenchman, Francois-Marie Raoult (1830-1901), established that partial pressure of components in diluted solutions is associated with their molar fraction. According to Raoult law. 

Arrhenius found his entry into the field through the work of the French chemist Francois Marie Raoult (1830-1901). Like Van t Hoff, Raoult studied solutions. His studies were climaxed in 1887 with his establishment of what is now called Raoulfs law ... 

Detailed studies of the vapor pressures of solutions containing nonvolatile solutes were carried out by Francois M. Raoult. His results are described by the equation known as Raoult s law ... 

In general the law holds only for dilute solutions, although some mixtures of liquids obey it over a whole range of concentrations. Such solutions are perfect solutions and occur when the intermolecular forces between molecules of the pure substances are similar to the forces between molecules of one and molecules of the other. Deviations in Raoult s law for mixtures of liquids cause the formation of azeotropes. The law was discovered by the French chemist Francois Raoult (1830-1901). 

The next major step was the enunciation of Raoult s law (Raoult 1887, 1888). In 1887, Francois Raoult published his investigations on the vapor pressure of the solvent in dilute solutions. He studied five solutes in water and 14 solutes in each of 11 organic solvents and found that the diminution of the vapor pressure of the solvent upon addition of a given (small) amount of solute was proportionally the same for all cases. The proportionality factor is the mole fraction of the solute. This may be expressed in the currently accepted notation as p° -pi p°X2 this is known as Raoult s law. Raoult had previously discovered the laws of freezing point depression and boiling point elevation (Raoult 1878, 1882), three of the so-called colligative properties of dilute solutions. 

In 1888, the French physical chemist Francois Raoult published his finding that when a dilute liquid solution of a volatile solvent and a nonelectrolyte solute is equilibrated with a gas phase, the partial pressure pA of the solvent in the gas phase is proportional to the mole fraction xa of the solvent in the solution ... 

M. Boirac, Ndcrologie Francois Raoult, Discours de M. Boirac, Recteur. Ann. 

Francois-Marie Raoult (1830-1901) A French chemist who discovered the depression of the freezing point of liquids by the presence of dissolved substances and found that the diminution of the vapor pressure of a solvent, caused by a substance dissolved In it, is proportional to the molecular weight of the substance dissolved. He also worked on phenomena of the voltaic cell. 

This relation was first pointed out by Francois Marie Raoult in 1886, and is called raoult s law. It is a good approximation for solutions in which the different molecules are very similar in size and polarity. Imagine a liquid (A) in equilibrium with its vapor (Fig. 10.6). For simplicity, we assume that there are only 15 A molecules in the container. In a unit time interval, each molecule in the liquid has a certain probability of escaping, and each gas molecule has a certain probability of returning to the liquid. In Fig. 10.6a (pure A), 100% of the molecules in the liquid are A molecules. In Fig. 10.6b (solution), only 44 = I = 83% of the molecules in the liquid are A molecules. When an A moleciJe escapes from the liquid, it must come out of the surface layer. But now, some of the A molecules in the surface have been replaced by B molecules. The probability that we will see, in unit time, an A molecule escaping from the solution has been decreased. We may suppose that the probability that some A molecule will escape from the liquid per unit time is cut down by the factor f. This reasoning is based on the assumption that each individual A molecule has the same chance of escaping whether it is surrounded by all A s or by some A s and some B s—true only if A and B are very much alike. However, the rate of re-... 

Figure 7.3 shows a plot of the partial pressures of two components of a solution that follows Raoults law. The straight lines between zero partial pressure and p are characteristic Raoult s-law behavior. (As required by the straight-line form of equation 7.13, the slope of each line is equal to the equilibrium vapor pressure of each component. The intercepts also equal p because the x-axis is mole fraction, which ranges from 0 to 1.) The following of Raoult s law is one requirement for defining an ideal solution other requirements of an ideal solution will be presented at the end of this section. The law is named after Francois-Marie Raoult, a nineteenth-century French chemist who spent twenty years studying the properties of solutions. 

Raoult s law is named for Francois Marie Raoult, 1830-1901, a French chemist who was one of the founders of physical chemistry. 

Equation 5.33 is Raoult s law (Francois Marie Raoult, France, 1830-1901), an approximate expression for the vapor pressure of the components of a mixture. 

M. Domard, Institut des Isotopes Radioactifs, 2, rue Francois Raoult, 38 - Grenoble J. Francois, C.R.M., 6, rue Boussingault, 67 - Strasbourg... 

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