Journal of Chemical Education最新文献

In this paper a new approach to presenting the Rayleigh–Ritz method to chemistry students is described. The emphasis is on the methodological aspects that students should concentrate on, rather than on computational issues (e.g., calculations of integrals). The method is illustrated by the example of its application to the problem of anharmonicity of the HCl molecule vibrations. An Excel workbook to perform calculations without distracting students from the essence of the method was prepared. The relevant integrals, including integrals for the anharmonic terms up the sixth order, were programmed using the well-known formulas. The Jacobi diagonalization procedure was implemented in Visual Basic as an Excel macro. This procedure can be easily used provided the Hamiltonian matrix is available. This matrix can be readily assembled from the precomputed integrals and adjusted according to the users’ needs, e.g., by straightforward inclusion of the desired anharmonic terms to the potential. Issues to be discussed with students based on the results obtained for the fourth-order anharmonic potential are also suggested. It is also highly recommended that students carry out similar calculations, e.g., by including higher order terms to see the changes in the oscillator energy levels. The workbook can be easily adapted for calculations on other diatomic molecules at any computational level. In addition, a Wolfram Mathematica notebook for performing similar calculations was also provided for the users’ convenience.

With the increasing complexity of analytical data nowadays, great reliance on statistical and chemometric software is quite common for scientists. Powerful open-source software, such as Python, R, and the commercial software MATLAB, demands good coding skills. Writing original code could be challenging for students with no prior programming experience. Orange Data Mining is a Python based visual programming software that has been used widely in many scientific publications. Principal component analysis (PCA) is one of the most common exploratory data analysis techniques with applications in outlier detection, dimensionality reduction, graphical clustering, and classification. By using a program workflow based on widgets (a computational unit within Orange), the task of PCA can be done very quickly. The same workflow could be used for different types of analytical data without the need for reprogramming again. The application of Orange Data Mining software to PCA exploratory analysis of sugar NIR spectral data from a portable NIR spectrometer will be demonstrated. Further data sets including multivariate coffee composition data, instant coffee FTIR spectra, vegetable oil fatty acid composition, and vegetable oil NMR spectra were given as Supporting Information to enhance the learning of software through repetition. From the demonstration, it can be easily seen how Orange Data Mining software will be useful for introducing PCA to the analytical curriculum.

The Quick Quantum Mechanical Spectra (Quick-QM-Spectra or QQMS) website has been developed as an easily accessible way for students (and others) to obtain spectral images and comma-separated values (CSV) files from the text output files of common open-source electronic structure programs. Unlike many of the highly powerful, yet more complicated visualization programs available, the QQMS website requires no software download (other than a standard Internet browser) or significant learning curve for anyone to use. IR, UV/vis, and Raman spectra can be obtained within seconds simply by uploading GAMESS, NWChem, and ORCA output to the QQMS website. IR and UV/vis spectra can also be obtained from a Psi4 output. The QQMS website is intended to be a simple time-saving tool that enables students (and others) to focus their effort on the analysis, not the generation, of theoretical spectra.

Tea has been implemented in various educational laboratories, often to demonstrate Le Châtelier’s principle. The color of tea can primarily be attributed to thearubigin species, and is an equilibrium between the lightly colored, weak acid reactant (TR) with a darkly colored anion (TR^–) and hydronium ion products. This system responds to the addition of an acid or base, thus allowing students to observe the response visually. Here, we have extended this concept to a chemical education lab experiment where students can quantitatively determine the chemical equilibrium constant of thearubigins in tea. This experiment allows students to gain experience with unit conversions, ICE tables, pH measurements, absorbance spectroscopy, calibration curves, and calculations of K_eq. Students measure the pH of tea to be 4.7–5.7 and by assumptions with respect to the concentrations of thearubigin species at equilibrium, students calculate an equilibrium constant (K_eq) of the aqueous thearubigin species of 3.6 × 10^–6 – 3.5 × 10^–5. Ultimately, students demonstrate qualitative and quantitative understanding of how applying Le Châtelier’s principle to an equilibrated system at a constant temperature does not alter the equilibrium constant.

A simple demonstration adaptable to classroom conditions is presented, which involves the preparation of raffle tickets using filter paper and the solution of selected fluorophores. With an appropriate dilution, the text written on the tickets is not visible to the naked eye; however, it becomes readable once put under a UV lamp. Besides being a conventional game of raffles with small giveaways, the activity can captivate and raise the spectators’ interest in a specific chemical phenomenon. Optionally, depending on the audience, the demonstration can be supplemented by an explanation of fluorescence, the presentation of some of the most important fluorophores, and a discussion of their applications.

Sense of belonging in postsecondary introductory chemistry classrooms has been correlated with success outcomes for students. Therefore, a surge of programming and initiatives has taken place to prioritize student success and wellbeing. However, there is a gap between practice and evaluation. Current instruments available to researchers and practitioners fall short of the nuance needed to capture the impact of these initiatives or were not developed for postsecondary chemistry classrooms. This study developed and evaluated a chemistry multidimensional belonging scale (CMBS) that can be used to measure four dimensions of students’ sense of belonging in chemistry classrooms. Survey development was based upon previous work that describes a theoretical framework and an iterative process of survey development, resulting in the CMBS, a 16 item Likert scale survey. To evaluate the survey, it was administered to two classes of first-semester general chemistry (N = 289), and the students’ responses were evaluated for internal structure, response process, and relations to external variables. The results evidenced the validity and reliability of the data produced by the CMBS. The resulting instrument items are included, and future work can utilize this survey to examine the generalizability of the findings or evaluate efforts to promote students’ sense of belonging.

The content and implementation of a one-credit course with built-in science outreach to the community partner, Girls, Inc., is described herein. This community-based learning (CBL) course aims at developing the undergraduates’ ability to plan, monitor, evaluate, and adjust to new learning environments by reflecting on their own learning and also to define their scientific identities. The course delivery is divided into five Training and Preparation sessions, seven Community Partner Interaction sessions, and two Assessment sessions. Throughout the semester, the participating students reflected on their experiences and contextualized the outreach within the educational theories discussed. Student feedback indicated a shift in the undergraduate students’ bias on gender in science, and the appreciation to have the opportunity for metacognitive reflection.

We present the development and evaluation of “da Vinci’s Curse”, a chemistry escape room experience designed to consolidate laboratory skills in a fun and interactive setting. Inspired by the maestro, Leonardo da Vinci, the escape room challenges students to complete a series of puzzles in teams to escape “da Vinci’s Curse”. Guided in their journey by instructional riddles from da Vinci himself, these puzzles focus on practical laboratory techniques including liquid–liquid extraction, acid–base behavior of functional groups, infrared spectroscopy, and thin-layer chromatography. Evaluation of the effectiveness of “da Vinci’s Curse” by a Likert methodology found that student confidence in a range of key laboratory, transferable, and employability skills increased significantly and that students enjoyed the experience of working with others in the laboratory.

Undergraduate students enrolled in the Quantitative Analysis laboratory course are often plagued with titration boredom (fatigue due to the repetition of titration-based experiments throughout the semester), often leading students to prioritize finishing quickly over learning essential skills. This has been previously shown to decrease motivation and engagement, which has been linked to decreased long-term retention of content knowledge and skills. One potential solution is the implementation of gamified experiments. We developed and implemented a novel gamified titration experiment to be used in the undergraduate Quantitative Analysis laboratory. This novel game, Quantimon, is a card game that allows students to work in teams with the goal of earning the highest proficiency in order to build their own character chemist. Students complete the laboratory experiment and answer questions following each task to earn proficiency cards. After each team has built their character chemist, they battle in gamified laboratory-based scenarios, where teams draw trivia cards that either give or take damage depending on correctness. Student motivation and details on experience during the gamified titration laboratory experiment were assessed using a developed survey. Details of the novel game have been described, with data indicating an increase in student motivation when completing the gamified laboratory experiment.

The use of educational games in Chemistry teaching has a history of 100 years, dating back to their first publication in 1925. Studies have shown the positive effects of this complementary learning strategy, such as increased motivation and improvements in the interpretation of symbols and concepts, especially in schools and universities. This review presents essential information on educational games for the scientific community of Chemistry, including titles, areas, and subareas of study covered, countries, number of publications, delivery methods and formats, the language used, categories and styles, and types of journals. The objective is to provide a broad overview of the evolution of research in the area, encouraging new productions and reproductions based on a detailed analysis of the collected data. The search was conducted in the Web of Science, Scopus, Dimensions, and Education Resources Information Center databases, which are some of the most widely used by researchers worldwide and provide highly reliable open-access journals. The bibliographic mapping covers the period from January 1925 to June 2024, identifying 735 relevant works. After careful analysis, which included the exclusion of duplicates and the application of inclusion and exclusion criteria, 311 complete articles were considered in this study. The method adopted was bibliometric analysis, specifically Performance Analysis, with a descriptive and analytical approach. The references extracted from this mapping were used to discuss and validate the findings and the evolution of the applicability of educational games in the teaching and learning of Chemistry throughout this centenary.