World Journal of Chemical Education

Undergraduate biochemistry students should have great familiarity with titration curves. These curves allow the prediction of protonation states, charges, and isoelectric points. Here we describe an experiment in which students identify four amino acids based on their titration behavior. Students make solutions of each unknown amino acid and monitor the change in pH upon adding aliquots of a strong base. They identify the amino acids based on the shapes of the curves. They annotate the plots with isoelectric points, pKas, buffering regions and the structures of the amino acids.

World Journal of Chemical Education. 2014, 2(4), 59-61. DOI: 10.12691/wjce-2-4-3
Pub. Date: January 01, 2015

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Extent of Reaction Balances: A Convenient Tool to Study Chemical Equilibria

by Juan José Baeza-Baeza and María Celia García-Alvarez-Coque

Original Research

The extent of a chemical reaction has received little attention in the early stages of Chemistry teaching, despite allowing a general way to work with chemical reactions and equilibria. In this article, the concepts of extent of reaction and extent of reaction balances are revised and several applications to study the change in the concentrations of the species involved in chemical reactions are described for both single and multiple systems. Extent of reaction balances allow a general treatment that can be applied to problems of diverse complexity involving different types of equilibria, either in the gas phase or in solution (acid-base, complexation, precipitation and redox reactions). This treatment depends exclusively on the reactions stoichiometry and can be taught at several levels, for single or coupled equilibria. Several examples are given, from basic problems adequate for High School Chemistry to problems for College Chemistry.

World Journal of Chemical Education. 2014, 2(4), 54-58. DOI: 10.12691/wjce-2-4-2
Pub. Date: December 21, 2014

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The Types and Inquiry Level of Chemistry Laboratory Courses in Ethiopia Higher Education Institutes: The Case of Practical Organic Chemistry I

by Belay Tafa

Original Research

The major objective of this study was to offer an overview of the current situation in the course content and inquiry level of practical courses in chemistry department of Ethiopian universities with a special reference to the course practical organic chemistry I. Practical Organic Chemistry I course material and the harmonized curriculum of chemistry were involved as the main source of data. The necessary data for the study was obtained from the deep content analysis of the course material. Qualitative and quantitative methods were employed to analyze data. The result indicated that the majority of the activities have lower inquiry level of one and the dominant practical work identified was demonstration type activity. Based on these findings, therefore, certain recommendations were forwarded.

World Journal of Chemical Education. 2014, 2(4), 48-53. DOI: 10.12691/wjce-2-4-1
Pub. Date: November 28, 2014

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