Volume 8, Issue 3

A Possible Electrochemical Route to a Thermodynamic Redox Reaction Equilibrium Constant in Secondary Education: An Attempt to Come from Science Fiction to Science Education?
Original Research
A description is given of an electrochemistry refresher course as a basis for tabulated standard electrode potentials using the Nernst equation and relating chemical equilibrium constants. In connection with their professional experiences the participating teachers carried out measurements of the voltage of a self-built electrochemical cell as described in a final examination task. In this task students had to calculate the voltage using tabulated E0 values. The sign of the measured and calculated voltage appeared to be different. Measurement of current-potential curves of different cells with the help of a Poggendorf compensation circuit affirmed the surmise of a thermodynamic context rather than an empirical one for the Nernst equation: reversible reactions have to be distinguished from spontaneous ones. Even the best measuring cells did not give a good correspondence simultaneously for E0 and the factor RT/nF in the Nernst equation, which was not only due to insufficient time to get equilibrium results. This led to the use of cells taken from literature and the concept of activity coefficient calculated from the Debije-Hückel theory. So generalisation (the mathematical form of the Nernst equation), idealisation (very diluted solution), modelling (corpuscularity) and specification (calculation of the activity coefficient) are necessary for a correct interpretation of apparent empirical values like a standard electrode potential or a chemical equilibrium constant.
World Journal of Chemical Education. 2020, 8(3), 128-140. DOI: 10.12691/wjce-8-3-5
Pub. Date: July 30, 2020
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Seasonal and Zodiac Sign Properties of the Citric Acid Cycle and the Grouping of Biochemically Important Functional Groups
Original Research
Properties of the intermediates from the citric acid cycle (TCA cycle) match the zodiac signs and correspond to the seasons of the year. The grouping of the twelve most important biochemical functional groups exhibits the same ratios that are typical for the zodiac signs.
World Journal of Chemical Education. 2020, 8(3), 122-127. DOI: 10.12691/wjce-8-3-4
Pub. Date: July 07, 2020
3564 Views903 Downloads
Mathematical Modeling in Secondary Chemistry Education: Chromatography
Original Research
The rapid advance in information technology requires further developments in all areas of education. In this context, one should think about going beyond the use of digital media for the mere presentation of scientific content. Interactive computer simulations allow quasi-experimental investigations of scientific phenomena but for students they usually remain black-box approaches. For a deeper understanding of phenomena, it is desirable to go one step further and set up computer codes based on a given microscopic model as part of the chemical education. Such approach allows teaching the scientific topic in more depth, fosters the awareness of the relevance of mathematics and computing in chemistry, and lastly supports the self-directed investigation of a scientific phenomenon. In addition, it gives students the opportunity to learn in general about modelling which has become an important contribution to chemistry and other natural and engineering sciences. Here we discuss basic chromatography with a simplistic stochastic simulation method suitable for upper secondary education. In addition, the analytical solution of the processes is given at the level of secondary mathematics. Chromatography itself is potentially treated in secondary education at various levels from paper chromatography to gas chromatography. This general knowledge makes it more accessible to students as a subject for deepening by modeling and simulation.
World Journal of Chemical Education. 2020, 8(3), 114-121. DOI: 10.12691/wjce-8-3-3
Pub. Date: June 16, 2020
5312 Views802 Downloads
Non-enzymatic Electrochemical Determination of Glucose Concentration
Original Research
There are a variety of applications for electrochemistry (including synthetic, physical and analytical chemistry), and here we present an experimental protocol for the non-enzymatic electrochemical quantitation of glucose in liquids that can be used in teaching laboratories. This offers an interesting experiential learning experience that is contextualized through a real world application where comparable technology the students employ touches the lives of humans across the world on a daily basis.
World Journal of Chemical Education. 2020, 8(3), 107-113. DOI: 10.12691/wjce-8-3-2
Pub. Date: June 03, 2020
6631 Views857 Downloads
Choose Your Own (Green) Adventure: A Solventless Aldol Condensation Experiment for the Organic Chemistry Laboratory
Original Research
Aldol condensation reactions are routinely used in organic chemistry teaching labs. In this experiment, we developed a greener method for the aldol condensation experiment of the Organic Chemistry II lab at North Carolina State University. To do this, we used the 12 Principles of Green Chemistry, and altered our current procedure to fit as many of them as possible. The main approach used throughout this process was developing aldol condensation reactions that were completely solventless. We currently have a procedure that allows for all possible combinations of two aldehydes: 4-tolualdehyde and 4-anisaldehyde, and two ketones: acetophenone and 4-methylacetophenone. We have developed a method that not only reduces solvent consumption, but also qualifies under 5 other green chemistry principles: prevention of waste, less hazardous chemical synthesis, reduction of derivatives, accident prevention, and atom economy. This new experimental design allows students to choose the compounds they would prefer to use from a list of available reagents therefore allowing a certain degree of lab personalization.
World Journal of Chemical Education. 2020, 8(3), 104-106. DOI: 10.12691/wjce-8-3-1
Pub. Date: May 25, 2020
4231 Views545 Downloads