Salting Effects as an Illustration of the Relative Strength of Intermolecular Forces
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[1] University High School
University High School
Estados Unidos
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[2] California State University
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- Localización: Journal of chemical education, ISSN 0021-9584, Vol. 87, Nº 12 (December), 2010, págs. 1332-1335
- Idioma: inglés
- Texto completo no disponible (Saber más ...)
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Resumen
This quick and inexpensive demonstration of the salting of an alcohol out of an aqueous solution illustrates the impact of intermolecular forces on solubility using materials familiar to many students. Ammonium sulfate (fertilizer) is added to an aqueous 35% solution of isopropyl alcohol (rubbing alcohol and water) containing food coloring as a visualizing agent. A colored alcohol layer will form above the colorless aqueous layer in 10−20 s showing that the ion−dipole interactions between the ammonium sulfate and water are stronger than the hydrogen bonds between isopropyl alcohol and water. Adding water to this two-layer mixture will restore the solution to a single layer, as there is sufficient solvent to dissolve both the ammonium sulfate and isopropyl alcohol. This demonstration is an illustration of intermolecular forces and solubility appropriate for high school and general chemistry courses.
