Partition Coefficients and Solvent Extraction
This page covers partition coefficients and their application in solvent extraction, an important purification technique in chemistry.
The partition coefficient describes how a solute distributes between two immiscible liquids. It is temperature-dependent but unaffected by adding more solvent or solute.
Example: The partition coefficient formula for sodium chloride between water and hexane is:
K = [salt(hexane)] / [salt(aq)]
Solvent extraction, a common application of partition coefficients, is used for purifying chemicals.
Highlight: It is more efficient to use small volumes of organic solvent in repeated extractions rather than one large volume in a single extraction.
The section also introduces acids and bases, explaining that hydrogen ions (H+) form hydronium ions (H3O+) in water. Water's amphoteric nature and its ionic product (Kw) are discussed.
Vocabulary: Amphoteric substances can behave as both acids and bases.