Determining the Energy of Activation of a Salt, Water, and Alcohol Emulsion

• Michael Nydegger ^[1] ; Ashlee Bartlett ^[1] ; Hannah R. Leverentz-Culp ^[2]
  1. [1] Spring Arbor University

     Spring Arbor University

     Township of Spring Arbor, Estados Unidos

     
  2. [2] Winona State University

     Winona State University

     City of Winona, Estados Unidos

     
• Localización: Journal of chemical education, ISSN 0021-9584, Vol. 97, Nº 10, 2020, págs. 3746-3750
• Idioma: inglés
• Texto completo no disponible (Saber más ...)
• Resumen

  • A highly visual, inexpensive, straightforward laboratory experiment for the determination of the activation energy of a demulsification process is presented. The experiment uses low-density polyethylene (LDPE) beads to clearly mark the interface between an NaCl(aq) solution and isopropanol. The NaCl(aq)–isopropanol system is shaken to produce an emulsion, and the rate of demulsification is subsequently observed at different temperatures. The Arrhenius equation is then used to relate the rate and temperature data to an energy of activation for the demulsification process. A total of 36 undergraduate laboratory groups in first-year chemistry courses performed this experiment. The students’ data consistently yielded linear Arrhenius plots with an average R2 value of 0.928 ± 0.035. The activation energy of the demulsification process described in this work was found to be 34.3 ± 2.5 kJ/mol. The reproducibility of the results, the simplicity of the data collection, and the low cost of the materials make this laboratory exercise easily adaptable to a variety of grade levels, from middle school students to first-year college students.