Adsorção e propriedades de volume de misturas binárias água álcool: um experimento didático com base em medidas de tensão superficial

Abstract

Recebido em 28/9/09; aceito em 2/3/10; publicado na web em 20/7/10 AN UNDERGRADUATE EXPERIMENT IN PHYSICAL CHEMISTRY: ADSORPTION AND BULK PROPERTIES OF ALCOHOL-WATER MIXTURES BASED ON SURFACE TENSION MEASUREMENTS. An undergraduate physical chemistry experiment based on the drop counting method for surface tension measurements is proposed to demonstrate adsorption isotherms of binary aqueous solutions of ethanol, n-propanol, and n-butanol. Excess surface is obtained by the derivative of surface tension taken with respect to alcohol activity, after this activity calculation using van Laar equation. Laboratory class contents are surface tension, excess surface, percolation of hydrogen bonds, micelle, activity, and ideal solution.