Journal of Chemical Education最新文献

Real-world safety case studies provide concrete examples of episodes that can be both instructive and memorable for students. We describe here a framework for teaching safety case studies using the RAMP risk management approach. Structured templates guide students to Recognize the hazards present, Assess the associated risks, and consider what risk Minimization and Preparation for emergencies steps were appropriate. The student is then guided to consider what RAMP steps were, or might have been, inadequately addressed. The process culminates with a root cause analysis that examines probable causes of the incident. This guided inquiry framework allows students to gain an understanding of risk management and reinforces the importance of the decision-making process for safety. The Supporting Information for this paper includes the templates, student instruction for the four parts of the process, an instructor’s guide, three examples of the process, and other resource material.

The preparation of n-bromobutane is one of the required training items in Experimental Organic Chemistry for undergraduates. However, there are still drawbacks: the reaction process is not easy to monitor, and the yield of n-bromobutane is low (∼50%) in the available experimental protocols. In this improved experiment, the visual preparation of n-bromobutane was realized through the ingenious use of a Dean–Stark apparatus. Moreover, the postprocessing steps of the reaction were simplified: while the reaction was proceeding, separation and purification were conducted at the same time, thus leading to an increase in product yield (from ∼50% to ∼70%). As a result, the improved protocol provides conveniences for students to observe the reaction process intuitively and accurately by using the obvious stratification phenomenon in the Dean–Stark apparatus for visual teaching. Moreover, it also expands the scope of the use of the Dean–Stark apparatus and stimulates students’ interest in learning organic chemistry. The experiment has good cost-effectiveness and takes ∼3 class hours, which is fairly suitable to be widely used in undergraduate teaching.

Chemistry in Everyday Life, a foundation level course, was developed and implemented for high school students at the Thammasat Secondary School, Thailand. The course was designed around the topic of influencing household attitudes about the relevance of chemistry. The goal was affective instructional engagement in beginning chemistry student learning. Principal chemistry content was taught, addressing three household-related items: (i) polymeric material utensils; (ii) detergents or cleaning products; and (iii) liquid hydrocarbon-based petroleum for vehicles. One research mode was to integrate explanatory writing assignments to help students identify socioscientific issues and conceptualize lesson content. Students understood chemistry concepts by constructing individual explanations of scientific phenomena. The quality of student submissions, learning difficulties, and course evaluations were evaluated. Results indicate that the course boosted student interest and self-efficacy in the chemistry learning engagement.

Electrophilic aromatic substitution (S_EAr) and nucleophilic aromatic substitution (S_NAr) reactions are among the most valuable reactions in the conversion of aromatic rings. While these reactions are typically covered in separate experiments in undergraduate organic courses, a continuous experimental setup elucidating both S_EAr and S_NAr processes remains unexplored in the literature for undergraduate laboratories. We herein described a two-step experimental design to cascade the S_EAr and S_NAr reactions, aiding students in better understanding the similarities and differences of these conversions as well as introducing the concept of umpolung. The experiment also reinforces students’ proficiency in fundamental organic synthesis techniques and workup procedures, such as TLC analysis, chromatography purification, recrystallization, and handling LRMS and NMR.

Due to safety concerns, a larger scale synthesis (0.5 mol) of dibenzyl ketone (1,3-diphenylpropanone, DBK) was performed for more than ten years as a class wide demonstration in the second-semester undergraduate organic chemistry teaching laboratories at the University of Texas at El Paso. This synthetic step was added to a seven-step convergent synthesis of hexaphenylbenzene found in Experimental Organic Chemistry: A Small-Scale Approach, 2nd ed. by Wilcox and Wilcox. Herein, we report a safer, small-scale (7 mmol) synthesis and purification of DBK which allows students to perform the experiment individually or in pairs. In addition, because the iron byproducts generated proved difficult to remove from used glassware, a cleaning protocol using concentrated black tea was also developed.

Thermodynamics forms an important part of the science and engineering curriculum at the undergraduate and graduate levels. Over the years, the importance of statistical mechanics and molecular simulations in the curriculum has increased. In this work, we present a pedagogical approach to the microcanonical formulation of statistical mechanics via its consistency with the combined first and second law of thermodynamics. We start with Boltzmann’s entropy formula and use differential calculus to establish that dE = TdS – PdV for an isolated, nonideal fluid in an arbitrary number of dimensions, with a constant number of particles (N), volume (V), and energy (E) and with temperature T, pressure P, and entropy S. To this end, we write the partition function for an isolated monatomic fluid. Furthermore, we derive the average of the inverse kinetic energy, which appears in the microcanonical ensemble, and show that it is equal to the inverse of the average kinetic energy, thus introducing the system’s temperature. Subsequently, we obtain an expression for the pressure of a system involving many-body interactions and introduce it in the combined first and second law via Clausius’s virial theorem. Overall, we show that the statistical mechanics of an isolated (microcanonical) nonideal fluid is consistent with the fundamental thermodynamic relationship dE = TdS – PdV, thereby providing deeper insight into equilibrium statistical thermodynamics. We also demonstrate that this material resulted in favorable learning outcomes when taught as a 1.5 h lecture; therefore, it may be incorporated into graduate-level courses on statistical mechanics and/or molecular simulations.

A key concept for students learning how computational chemistry calculates the electronic structure of molecules involves translating qualitative concepts like the projector operator method and the Schrödinger Equation to the quantitative methods that approximate the many-body problem. The following project is for an independent study student or an undergraduate researcher desiring training in theoretical chemistry. The C₅ symmetry of the pentafluoroxenate(IV) anion showcases that “bonds form when orbitals overlap.” The project guides students to see how number theory is incorporated into molecular structures and the nature of shapes. Additionally, [XeF₅]⁻ has minimal d-orbital contributions, so the student does not require previous experience with d-orbital splitting. The qualitative analysis of the pentagonal planar, D_5h pentafluoroxenate(IV) anion [XeF₅]⁻ was performed using group theory and the projection operator method. The computational approach used a population analysis of [XeF₅]⁻ to obtain the electronic structure.

It is well understood that the creative processes behind art forms, including music, are highly subjective and are based on personal interpretation. This raises the question: can music be effectively integrated into the teaching of more objective subjects, such as chemistry, if done through a systematic and structured framework? In this work, we rationally constructed the mapping between small molecules and chords. We found a strong correlation between the molecular stability and the music type from the interpretation of chemical bonding pictures. This correlation helps students understand the beauty and artistry of chemistry and chords in music. Furthermore, we observed some small imperfections in the molecule mappings of certain real-world chord progressions, which present opportunities for refinement through optimization of the underlying molecular cohesive energy. We demonstrated that the basic chemical bonding picture could provide objective understanding or even standards for music composing. Most small-molecule structures, such as amino acids, can be objectively transformed into reasonable chord combinations, and some real-world music chords exist in these molecular chords. Therefore, students can “play” the molecules using real instruments, and this method is practicable in organic chemistry education.

It is common for conversations about improving college chemistry learning to focus largely (or solely) on changing the way classes are taught. We advocate treating chemistry courses as more than a collection of teaching methods; what is taught and assessed are likely at least as important as how courses are taught. To demonstrate the utility of a nuanced approach for characterizing learning environments, we report a study on the impact of changing instructional practices in a large-enrollment organic chemistry course. Two types of enactment were compared: one in which lecture was the sole instructional practice used and one in which classes spent ∼33% of their time together engaging with lecture-embedded questions. Analyses of what was taught and assessed demonstrates that both types of course placed substantial emphasis, in-class and on assessments, on students using fundamental disciplinary ideas (e.g., energy, bonding) to predict, explain, and model phenomena. We found that integrating interactivity into large group meetings, while keeping assessments and pacing the same, had no substantive impact on student performance on instructor-authored assessments or the correctness of explanations elicited by researcher-authored instruments. Encouragingly, many students in both cohorts were supported in using core ideas to construct expert-like explanations and models for phenomena in high- and low-stakes assessments. However, both more- and less-interactive classes were similarly inequitable based on race and first-generation status, and to a lesser extent, binary gender. This suggests that, even in a model-centered organic chemistry course, addressing persistent inequities will require more fundamental changes than simply lecturing less.

Highlighting the number of ways that chemical education has thrived with publication in the Journal of Chemical Education outpaced the available space in the 100th volume celebration, published in 2023. Thus, one key aspect of learning chemistry, outreach about the nature and applications of chemistry, remains to be highlighted now, in the 101st volume. The creativity and innovation of chemistry educators in devising and staging such outreach is as enduring as any subfield of chemistry. A new collection of over 50 articles from the past century (plus one year) has been gathered and posted here (https://pubs.acs.org/page/jceda8/vi/outreach2024) as a look at the evolution of outreach efforts in chemical education.