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These properties are colligative in systems where the solute is essentially confined to the liquid phase. Boiling point elevation (like vapor pressure lowering) is colligative for non-volatile solutes where the solute presence in the gas phase is negligible.
If the solute is volatile, one of the key assumptions used in deriving the formula is not true because the equation derived is for solutions of non-volatile solutes in a volatile solvent. In the case of volatile solutes, the equation can represent a mixture of volatile compounds more accurately, and the effect of the solute on the boiling point ...
Freezing-point depression is a drop in the maximum temperature at which a substance freezes, caused when a smaller amount of another, non-volatile substance is added. Examples include adding salt into water (used in ice cream makers and for de-icing roads), alcohol in water, ethylene or propylene glycol in water (used in antifreeze in cars ...
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.
Henry's law has been shown to apply to a wide range of solutes in the limit of infinite dilution (x → 0), including non-volatile substances such as sucrose. In these cases, it is necessary to state the law in terms of chemical potentials. For a solute in an ideal dilute solution, the chemical potential depends only on the concentration.
For example, carboxylic acids such as acetic acid (ethanoic acid) or benzoic acid form dimers in benzene, so that the number of solute particles is half the number of acid molecules. When solute particles dissociate in solution, i is greater than 1 (e.g. sodium chloride in water, potassium chloride in water, magnesium chloride in water).
Total dissolved solids include both volatile and non-volatile solids. Volatile solids are ones that can easily go from a solid to a gaseous state. Non-volatile solids must be heated to a high temperature, typically 550 °C, in order to achieve this state change. Examples of non-volatile substances include salts and sugars. [3]
Evaporation removes volatile liquids from non-volatile solutes, which cannot be done through filtration due to the small size of the substances. Liquid–liquid extraction removes an impurity or recovers a desired product by dissolving the crude material in a solvent in which other components of the feed material are soluble.