Journal of Chemical Education最新文献

While solid-state syntheses continue to advance, so do the methodologies required to make a robust working electrode with such materials. These include vapor deposition, electrodeposition, and single layer deposition. Although these avenues provide incredibly precise electrodes, it consequently widens the gap between state of the art and practicality in traditional laboratory facilities, especially with less specialized equipment and limited time in the undergraduate laboratory. Carbon tape electrodes bridge this gap by providing appropriate stability and ease of preparation. Carbon tape electrodes are shown herein to be effective in surveying metal oxide powders as Oxygen Evolution Reaction (OER) catalysts in a straightforward inorganic chemistry laboratory experiment. The electrodes’ versatility allows for the catalysts to be comparatively benchmarked against one another while also observing the pH dependence of water splitting. These electrodes show robust, consistent behavior under aqueous and nonaqueous conditions that facilitates their use as a general-purpose electrode for solids, helping to overcome a longstanding aversion to the use of electrochemistry in undergraduate inorganic chemistry laboratories.

A comprehensive experimental study focusing on the preparation and application of cork-based Covalent Organic Frameworks (COFs) as composite materials for the separation of oil and water is proposed for senior students. COFs were uniformly deposited on the microchannels of cork common in daily life as the substrate, and a Cork@COFs composite with a porous structure was constructed for oil–water separation. Composite materials were prepared through the in situ growth method, and the resultant composite exhibits the capability for selective oil adsorption. Additionally, the material is both recyclable and reusable. In this lab, students will be able to practice the preparation of a novel composite and learn to analyze several characterization techniques, including powder X-ray diffraction (PXRD), scanning electron microscopy (SEM), thermogravimetric analysis (TG), Fourier transform infrared (FT-IR) spectroscopy, and the contact angle test. They will also evaluate the performance of the composite by testing its selective oil adsorption and reusability. After the completion of the experiment, students present their findings to undergraduate students with a chemistry background in their sophomore and junior years in the form of a scientific report including some experimental demonstrations. The purpose of this comprehensive experiment is (1) to understand the preparation method and significance of composite materials, (2) to deepen the understanding of chemical concepts such as surface functionality, contact angle, and hydrophobicity, (3) to realize that common materials in daily life can be well combined with cutting-edge chemical knowledge, and (4) to exercise students’ experimental operation ability and scientific research expression ability. This experiment can introduce students to the synthesis of COFs, Cork@COFs composite materials, the principles for using analytical instruments, and the characterization of the hydrophobic properties of materials. The presentation allows more students to gain insights into cutting-edge chemical knowledge and inspires their thinking.

While chemical formulas and valences are among the most commonly used tools in chemistry learning, there is a lack of educational resources that facilitate mastering this knowledge in an inquisitive and interactive mode. To this end, we introduce the “Upgradable, Formula, and Valence (UFV)” Game, which aims to explain the concepts, rules, and laws of chemical formula and valence. To make the resource more flexible, we also illustrate modifications of the game so that the game is suitable for students at different learning stages. Feedback from various groups supports the conclusion that the UFV Game is a valuable tool for teaching the topic of chemical formula and valence.

An in-silico exercise was developed for a general chemistry laboratory course at St. Bonaventure University in which students examined potential energy surfaces, molecular orbital diagrams, and how bond orders and Lewis structures are connected. Pre- and post-assessment data suggests that, though students learned from the exercise, they are not connecting the concepts of bond order, Lewis structures, and resonance. There was a statistically significant improvement in the assessment scores before and after the laboratory experiment, and there was no statistical difference between the post-assessment and the follow-up assessment, which occurred after students completed the lab report 1 week after the initial experiment. The data suggest an improved understanding of computational chemistry concepts as well as improvement in the individual concepts of resonance, Lewis structures, and bond orders. However, an assessment question connecting these concepts did not show an improvement. An additional questionnaire was conducted to explore this discrepancy. This study indicates that more investigation is necessary with regard to students’ ability to make logical connections among bond orders, Lewis structures, and resonance.

Given the severe pollution caused by traditional plastics, biodegradable plastic products (BPPs) have received great attention and are appearing in people’s lives in the form of packaging bags, tableware, etc. Whether a wide variety of BPPs can truly degrade depends on the environment. Aerobic composting is the arbitration method to evaluate the degradability of BPPs in a premarket review, so only the aerobic degradability of BPPs can be guaranteed. Anaerobic digestion has become an irreplaceable part of the global carbon cycle and a mainstream technique to dispose of organic wastes. However, little attention has been given to the anaerobic degradation of BPPs, which may cause environmental pollution if BPPs are not degraded within a short time period. Students are not aware of these issues. Therefore, the teacher carried out teaching reforms in biochemistry course by designing anaerobic degradation of commercially available BPPs as a laboratory exercise for undergraduate students to form a correct understanding of the actual anaerobic degradation performance of BPPs, establish a more comprehensive theoretical knowledge framework of catabolism in biochemistry course, and train their hands-on ability and operation skills. This paper provides an introduction to the experimental design and teaching process of the anaerobic degradation of BPPs, and the results show that the degradation degree and rate are closely related to the components of BPPs. The results of the quizzes and questionnaires show that teaching reform is not only beneficial for deepening students’ impression and understanding of anaerobic catabolism from ubiquitous BPPs in everyday life but also helpful for promoting their environmental awareness by selecting and using BPPs with better degradability. This teaching reform offers references and guidance for the teaching practice in courses like biochemistry, environmental microbiology, environmental chemistry, and waste treatment.

The need for educational resources that effectively address contemporary scientific and societal challenges is exemplified by the global issue of climate change. This article describes a lesson utilizing multiple PhET sims in a general chemistry course examining greenhouse gases and their contribution to global warming. This is a cumulative lesson that integrates topics from earlier in the course such as Lewis structures, VSEPR predicted geometries, and molecular polarity. The lesson plan also incorporates a socio-political context, which includes exploring the views of citizens from various countries and analyzing the opinions of current American politicians on climate change. Student feedback highlights the strong appeal of this approach, noting particularly its relevance and effectiveness in linking scientific principles to real-world issues.

A comprehensive teaching experiment plan tailored for third-year undergraduates has been developed. Initially, instructors synthesize (E)-2-(4-((4-(2-hydroxyethoxy)-3-methylphenyl)diazenyl)phenoxy)-ethan-1-ol(M-Azo-2) monomer as part of the preclass preparation. Subsequently, students perform an acylation reaction experiment to prepare an azobenzene derivative containing cross-linking points on both sides. This derivative is then combined with poly(ethylene glycol) dimethacrylate in the absence of external solvent under conditions conducive to radical polymerization, resulting in a thin film that exhibits light-wet dual-stimulation responsiveness. This process enables students to comprehend both the chemical reactivity and photoisomerization propensity of azobenzene to effectively bridge elements of organic chemistry and polymer chemistry. The experiment demonstrates three vivid and novel biomimetic phenomena: “color-changing flowers”, “phototropic seedlings”, and “mimosa”, which display photochromic, light-induced deformation, and humidity-responsive behavior of the film, respectively. This experiment enhances students’ appreciation for the application potential of biomimetic materials and fosters innovative scientific thinking.

The escalating demand for rare earth elements (REEs) in industries such as batteries, electronics, and nuclear sectors necessitates their extraction using leaching methods. However, mining operations targeting low-content rare earth resources generate substantial waste, which contains carcinogenic and genotoxic REEs, posing a severe ecological pollution risk. Moreover, with changes in the international landscape and the nonrenewable nature of rare earth resources, efficient extraction, and recycling of these elements are of paramount importance. Electrochemical methods have emerged as a promising approach due to their selectivity and sustainability in ion extraction and separation. This experimental design focuses on extracting Ce³⁺ from solution with low-concentration rare earth ions using electrochemical techniques. The carefully devised procedures encompass the preparation of simulated Ce³⁺ salt solution, the electrochemical extraction of Ce³⁺, and the subsequent residual concentration determination. Through these steps, students will gain hands-on experience with laboratory operations and techniques associated with mineral engineering and electrochemical extraction. Participating in this experimental design offers students not only practical skills but also the opportunity to develop critical thinking abilities, analytical prowess, and an understanding of the sustainability and environmental implications of electrochemical extraction. This practical experience serves as a solid foundation for their future work and serves to stimulate their interest in scientific research, fostering a drive to dedicate further studies in the related areas.

Catalysis is an important discipline in modern chemistry and chemical engineering curricula. However, the interdisciplinary nature of catalysis poses significant challenges for teaching, particularly in organizing practical education. This article introduces a problem-based group assignment for a master’s course on catalysis. In this open-ended assignment, the student groups receive real data sets of raw kinetic and characterization results. Their task is to analyze and cross-reference the data, describe their findings in a concise report and presentation, and provide recommendations for further development of the catalytic system. The assignment helps students practice essential skills of complex data analysis and establishing structure–performance relationships, preparing them to tackle real-world challenges in catalysis. The assessment results indicate that the students have mastered these concepts. Finally, student feedback surveys demonstrate that the assignment is well-received by the students.

We present a suite of three workbooks implementing different methods and levels of approximations of quantum chemistry for elements from hydrogen to beryllium: two variants of Hartree–Fock (HF) of increasing complexity and the local spin-density approximation (LSDA) of density functional theory (DFT). Hydrogen-like basis functions for the 1s and 2s orbitals have been chosen, with associated effective charges treated as adjustable parameters. Instead of solving self-consistent equations, the total energy is minimized directly with respect to the orbital effective charges with the aid of the Solver add-in of Excel or by means of the virial theorem. The workbooks provide interactive input of the spin occupations of 1s and 2s orbitals, thus allowing calculation of the total energy not only of the ground-state neutral atoms but also of the first excited singlet and triplet states of helium and helium-like atoms, of the hydrogen anion H^– (hydride), and of the lithium and beryllium cations. The calculated total energies are compatible with those obtained by elaborated general-purpose quantum chemistry programs. The workbooks are suitable for upper-division undergraduates or postgraduate students with no previous programming experience. They are open for upgrade and could be used for different forms of computer-based learning in the frame of classroom activities or coursework assignments. The educational outcomes of using spreadsheets in the teaching environment have been quantified by means of Hake’s normalized gain analysis.