by R. Sanjeev, D. A. Padmavathi and V. Jagannadham
Original Research
No physical or physical-organic chemistry laboratory goes without a single instrument. To measure conductance we use conductometer, pH meter for measuring pH, colorimeter for absorbance, viscometer for viscosity, potentiometer for emf, polarimeter for angle of rotation, and several other instruments for different physical properties. But when it comes to the turn of thermodynamic or activation parameters, we don’t have any meters. The only way to evaluate all the thermodynamic or activation parameters is the use of some empirical equations available in many physical chemistry text books. Most often it is very easy to interpret the enthalpy change and free energy change in thermodynamics and the corresponding activation parameters in chemical kinetics. When it comes to interpretation of change of entropy or change of entropy of activation, more often it frightens than enlightens a new teacher while teaching and the students while learning. The classical thermodynamic entropy change is well explained by Atkins in terms of a sneeze in a busy street generates less additional disorder than the same sneeze in a quiet library (Figure 1) . The two environments are analogues of high and low temperatures, respectively. In this article making use of Eyring equation a factor usually called ‘universal factor’ is derived and made use as a ‘yard stick’ to interpreting the change in entropy of activation for physical or physical-organic chemistry senior undergraduate and graduate students’ class-room.
World Journal of Chemical Education. 2018, 6(1), 78-81. DOI: 10.12691/wjce-6-1-12
Pub. Date: January 26, 2018
11951 Views3172 Downloads1 Likes
by Elena von Hoff, Stefanie Waitz, Felix Kollenda and Thomas Waitz
Original Research
Within this article we present the synthesis of coin metal nanoparticles and nanoporous surfaces by cathodic corrosion as school experiments. We further present two experiments utilizing the obtained materials as catalysts; the catalytic decomposition of hydrogen peroxide and the platinum catalyzed chemiluminescence of lucigenin.
World Journal of Chemical Education. 2018, 6(1), 72-77. DOI: 10.12691/wjce-6-1-11
Pub. Date: January 26, 2018
15478 Views3723 Downloads3 Likes
by Dominique Rosenberg, Svenja Pansegrau, Mirco Wachholz, Anja Köppen, Maike Busker and Walter Jansen
Original Research
In the last few years the number of renewable energy sources (e.g. wind or solar energy) increased drastically. The availability of solar energy depends on the amount of daily sun light and the availability of electric power from wind turbines is linked to the available wind offered by nature. The increase of power from renewable energy sources has to be combined with innovative energy storage systems. Solar, wind and other renewable energy sources are intermittent energy sources. Consequently, with more renewable energy sources the amount of intermittent energy increases, too. Due to this, there is a need for more and more flexible and efficient energy storage systems with high capacities to guarantee the stability of the electric grid. Such energy storage systems, which are discussed right at the moment, are so called flow batteries. This article presents an experimental set-up that demonstrates the functionality of Redox-Flow-Batteries to students in chemistry lessons. Such efficient organic Redox-Flow-Batteries can use hair dyes like Phenylenediamine and pharmaceuticals such as Paracetamol. The decomposition product of Paracetamol, p-Aminophenol proved to be a particular suitable candidate, which is shown via cyclic voltammetry.
World Journal of Chemical Education. 2018, 6(1), 63-71. DOI: 10.12691/wjce-6-1-10
Pub. Date: January 26, 2018
25167 Views3527 Downloads
by Amitabh Banerji, Ann-Kathrin Schönbein and Lena Halbrügge
Original Research
Organic light emitting diodes (OLEDs) are modern illuminants of the next generation. OLEDs use (among others) semiconducting polymers for light emission and open the pathway to innovative applications as flexible or transparent displays or luminaire. For the school-implementation of OLEDs low-cost experiments and teaching materials have been developed earlier. This contribution delivers a school-experiment for the synthesis of a semiconducting polymer and presents a successful example of a curricular innovation based on the cooperation between subject science and science education.
World Journal of Chemical Education. 2018, 6(1), 54-62. DOI: 10.12691/wjce-6-1-9
Pub. Date: January 26, 2018
20440 Views3438 Downloads3 Likes
by Andreas Schedy, Dominik Quarthal and Marco Oetken
Original Research
The two-dimensional modification of carbon which is also known as “graphene” is an extremely interesting material due to its physical properties, such as a very high electrical conductivity and an intrinsic mechanical strength that is even better than that of steel. For that reason, it has already been called the “miracle material“ of the 21st century. Up to now, the synthesis of graphene was to dangerous to implement it into the school curricula. The authors present a method of synthesizing graphene which can be put into practice at school without hesitation. Following experiments show the varying properties of graphene oxide and graphene during synthesis. In this way, different structure-property relationships, which appear to be one of the most important concepts in chemistry lessons, can be analyzed.
World Journal of Chemical Education. 2018, 6(1), 43-53. DOI: 10.12691/wjce-6-1-8
Pub. Date: January 26, 2018
22042 Views3383 Downloads3 Likes
by Claudia Bohrmann-Linde and Diana Zeller
Original Research
Alternative solar cells on the basis of titanium dioxide are subject of intense research. For the integration of this topic into the chemistry curriculum a set of experiments with photogalvanic cells has been developed. Titania phototelectrodes need to be irradiated with UV light, but the spectrum of solar light contains only little UV radiation. Thus photosensitizers are needed that harvest visible light. Here we present a series of experiments with different dye solutions that can serve as an alternative to the priorly used anthocyanins in the chemistry classroom. The dyes presented are more stable and also work as sensitizers in titania-based photogalvanic cells.
World Journal of Chemical Education. 2018, 6(1), 36-42. DOI: 10.12691/wjce-6-1-7
Pub. Date: January 26, 2018
17358 Views3538 Downloads1 Likes
by Patrick Schairer, Stephan Wagner and Ekkehard Geidel
Original Research
To understand basic principles about the interaction of electromagnetic radiation with matter is often a challenge in chemical education due to the difficult theoretical background of this topic. The present contribution therefore offers an experimental based introduction into the basic principles of UV/Vis spectroscopy following a three-step strategy. The starting point is to construct a simple self-built spectrometer working within the visible range of light. Learners can explore the most important components of such a device and understand their functions without previous knowledge. In a second step, emission spectra of different common light sources are investigated and compared. Finally, spectroscopic experiments are suggested for chemical education such as the qualitative detection of cations and the quantitative analysis of the dye carmine in food. This context-based introduction links chemical applications with the everyday life. It can be presumed that this way, learners are provided an easier access to radiation-matter interaction.
World Journal of Chemical Education. 2018, 6(1), 29-35. DOI: 10.12691/wjce-6-1-6
Pub. Date: January 26, 2018
17108 Views3063 Downloads3 Likes
by M. Ducci
Original Research
Chemistry and life are undisputedly connected and always interdependent. Hence, it must be an essential aim to underline the value of this correlation in the light of our basic knowledge of chemistry and our general education. Moreover, it is important to relate chemical ideas with observations of daily life and living causes. In order to meet the aims of motivating and modern chemistry lessons, the author has developed a unit based on experiments exploring so-called Magic Markers. Ordinary looking felt pens change their colors when they are painted over by Magic Pens. To research on the chemical principles underlying this effect, number of simple but astonishing experiments suitable for students has been developed.
World Journal of Chemical Education. 2018, 6(1), 24-28. DOI: 10.12691/wjce-6-1-5
Pub. Date: January 26, 2018
18959 Views2554 Downloads
by Catharina Schmitt and Michael Schween
Original Research
Mechanistic problem-solving is the scientific core competence of organic chemistry. Hence, many students struggle with developing multivariate mechanistic thinking. They very often rely on memorized rules and propose products without providing a detailed mechanistic pathway. They simply apply problem-solving strategies from general chemistry, which is more product-oriented than organic chemistry. A process-oriented view that is highly demanded in organic chemistry requires the understanding and connection of basic principles and concepts. In order to practice the process-oriented approach and introduce advanced German high school students to mechanistic thinking, we developed a set of three new experiments to generate carbocations in model reactions for the observation of reactive intermediates. Trityl cations proved to be the best ones for an experimental investigation of a reaction’s progress which is accessible with a simple analysis that generates explicit results by changes in color and electric conductivity. The experiments are arranged in a guided inquiry workshop of six steps alternating theoretical (oral group discussions) and experimental phases.
World Journal of Chemical Education. 2018, 6(1), 18-23. DOI: 10.12691/wjce-6-1-4
Pub. Date: January 26, 2018
21011 Views3231 Downloads2 Likes
by Michael W. Tausch
World Journal of Chemical Education. 2018, 6(1), 14-17. DOI: 10.12691/wjce-6-1-3
Pub. Date: January 26, 2018
11557 Views2250 Downloads
by A. Habekost
Original Research
There is strong interest in developing batteries to complement lithium ion and fuel cell batteries. Vanadium redox flow batteries (VRFBs) seem to be suitable as large-scale energy storage systems. In these systems, vanadium species act as both electrolyte and active material. Since 1980, the pioneer of VRFB, Maria Skyllos-Kazacos from the University of New South Wales in Australia, has published a vast number of papers about electrode materials, membranes and combinations of vanadium and other redox active species. In chemistry didactics, these investigations pose a significant challenge: it is hard to transform these innovative developments into sound and easy to create experiments. Three experiments are presented here to introduce students to the capabilities of VRFBs with different electrodes and membranes for battery development.
World Journal of Chemical Education. 2018, 6(1), 8-13. DOI: 10.12691/wjce-6-1-2
Pub. Date: January 26, 2018
22579 Views3193 Downloads
by P. Heinzerling and M. Oetken
Original Research
Nanoscience seems to be a main topic of this century. The chemical fundamentals are very old and named colloids since Graham in 1861. The acronym nano has been introduced in 1960 at a conference of measures and weights in Paris. In 1982 Binnig and Rohrer invented the scanning tunnel microscope(STM) and four years later Binnig the atomic force microscope(AFM). These microscopes are the main tools for the nanotechnology and from this times the number of publications exploded. In this article we’ll focus on the chemical aspects of nanotechnology and how to implement experiments into school.
World Journal of Chemical Education. 2018, 6(1), 1-7. DOI: 10.12691/wjce-6-1-1
Pub. Date: January 26, 2018
24376 Views2741 Downloads1 Likes