Colligative property

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In physical chemistry of dilute solutions, the colligative property (from Latin colligere "collect") is a substance property (e.g. vapor pressure) that only depends on the number of particles (i.e. the amount of substance ) of the dissolved component, but not on the type of the particles or their chemical composition.

examples are

The colligative properties are only strictly independent of the type of particle if they do not participate in the phase transition. This applies to vapor pressure depression and boiling point elevation, so for dissolved substances compared to solvent negligible vapor pressure have so z. B. for salts that are dissolved in water, but not for a solution of ethanol in water.

Physically, the colligative properties can be derived from the fact that the dissolved substances reduce the chemical potential of the solvent due to their entropy of mixing .

See also

Web links

Individual evidence

  1. Bruno P. Kremer, Horst Bannwarth: Introduction to Laboratory Practice . Springer, Berlin Heidelberg 2014, ISBN 978-3-642-54333-3 , p. 135 , doi : 10.1007 / 978-3-642-54334-0 .
  2. a b c d Brockhaus ABC Chemie , VEB FA Brockhaus Verlag Leipzig 1965, p. 705.