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Raoult's law (/ ˈ r ɑː uː l z / law) is a relation of physical chemistry, with implications in thermodynamics.Proposed by French chemist François-Marie Raoult in 1887, [1] [2] it states that the partial pressure of each component of an ideal mixture of liquids is equal to the vapor pressure of the pure component (liquid or solid) multiplied by its mole fraction in the mixture.
In thermodynamics, an activity coefficient is a factor used to account for deviation of a mixture of chemical substances from ideal behaviour. [1] In an ideal mixture, the microscopic interactions between each pair of chemical species are the same (or macroscopically equivalent, the enthalpy change of solution and volume variation in mixing is zero) and, as a result, properties of the mixtures ...
The simplest definition is that an ideal solution is a solution for which each component obeys Raoult's law = for all compositions. Here p i {\displaystyle p_{i}} is the vapor pressure of component i {\displaystyle i} above the solution, x i {\displaystyle x_{i}} is its mole fraction and p i ∗ {\displaystyle p_{i}^{*}} is the vapor pressure ...
The relative activity of a species i, denoted a i, is defined [4] [5] as: = where μ i is the (molar) chemical potential of the species i under the conditions of interest, μ o i is the (molar) chemical potential of that species under some defined set of standard conditions, R is the gas constant, T is the thermodynamic temperature and e is the exponential constant.
Raoult's law is applicable only to non-electrolytes (uncharged species); it is most appropriate for non-polar molecules with only weak intermolecular attractions (such as London forces). Systems that have vapor pressures higher than indicated by the above formula are said to have positive deviations.
where is the chemical potential of the pure solvent and is the chemical potential of the solvent in a solution, M A is its molar mass, x A its mole fraction, R the gas constant and T the temperature in Kelvin. [1] The latter osmotic coefficient is sometimes called the rational osmotic coefficient. The values for the two definitions are ...
François-Marie Raoult (/ r ɑː ˈ uː l /; 10 May 1830 – 1 April 1901) was a French chemist who conducted research into the behavior of solutions, especially their physical properties. Life and work
The Margules activity model is a simple thermodynamic model for the excess Gibbs free energy of a liquid mixture introduced in 1895 by Max Margules. [1] [2] After Lewis had introduced the concept of the activity coefficient, the model could be used to derive an expression for the activity coefficients of a compound i in a liquid, a measure for the deviation from ideal solubility, also known as ...