Journal of Chemical Education最新文献

Explicit metacognitive interventions in undergraduate chemistry courses have been shown to improve student outcomes. Less studied have been the outcomes of students who implicitly and frequently practice metacognition and the resultant effects on the student-instructor relationship. In this project set within a large enrollment introductory chemistry course, we elevated student voice and enhanced student-instructor communication through weekly metacognitive reporting to study the characteristics of reporting students and their perceptions of the effects of metacognitive reporting. Data on course success and gender of reporting relative to non-reporting students were quantitatively analyzed using standard statistical techniques. Inductive thematic coding was used to qualitatively assess student responses to open-ended post-survey questions on perceived value of metacognitive reporting. Reporting students finished the semester with a final course grade point average 0.64 points higher than non-reporting students. In addition, reporting students were more successful (more ABC grades) than non-reporting students though small effect sizes and lack of directional causality limit data interpretation. However, female students tended to engage in reporting at a higher rate than did male students. Metacognitive reporting helped to establish a more positive and productive student-instructor relationship via enhanced student communication (i.e., student voice) that informed just-in-time teaching modifications. Students indicated that the metacognitive reporting assisted them in focusing their studies on more challenging topics and in modifying their study habits. In addition, students recognized that their instructors were reading and responding to the reports, which improved overall student-instructor interactions and their view of the instructor as beneficent. Based on these findings, it is recommended that instructors create frequent, low-stakes assignments built into the course structure to support their students' implicit use of metacognition with the broad goal of growing metacognitive strategies over time.

Explicit metacognitive interventions in undergraduate chemistry courses have been shown to improve student outcomes. Less studied have been the outcomes of students who implicitly and frequently practice metacognition and the resultant effects on the student-instructor relationship. In this project set within a large enrollment introductory chemistry course, we elevated student voice and enhanced student-instructor communication through weekly metacognitive reporting to study the characteristics of reporting students and their perceptions of the effects of metacognitive reporting. Data on course success and gender of reporting relative to non-reporting students were quantitatively analyzed using standard statistical techniques. Inductive thematic coding was used to qualitatively assess student responses to open-ended post-survey questions on perceived value of metacognitive reporting. Reporting students finished the semester with a final course grade point average 0.64 points higher than non-reporting students. In addition, reporting students were more successful (more ABC grades) than non-reporting students though small effect sizes and lack of directional causality limit data interpretation. However, female students tended to engage in reporting at a higher rate than did male students. Metacognitive reporting helped to establish a more positive and productive student-instructor relationship via enhanced student communication (i.e., student voice) that informed just-in-time teaching modifications. Students indicated that the metacognitive reporting assisted them in focusing their studies on more challenging topics and in modifying their study habits. In addition, students recognized that their instructors were reading and responding to the reports, which improved overall student-instructor interactions and their view of the instructor as beneficent. Based on these findings, it is recommended that instructors create frequent, low-stakes assignments built into the course structure to support their students’ implicit use of metacognition with the broad goal of growing metacognitive strategies over time.

The concepts of electronegativity and classical electronegativity scales are briefly described. Electronegativity scales have practical quantitative applications, and this work suggests activities which can assist students select the scales for use in chemistry applications. It provided examples of the use of an appropriate electronegativity scale, for estimating bond lengths, bond dissociation energies, and dipole moments. Expressions are introduced for estimating internuclear distances in ionic, covalent, and intermetallic compounds and bond dissociation energies. Estimated values of bond lengths, bond energies, and dipole moments using different electronegativity scales are compared with experimental values and show that the levels of performance are not the same for different electronegativity scales. Additional proposed activities are included.

This study presents a comprehensive bibliometric analysis of research on nanotechnology in education utilizing data from the Web of Science (WoS) and Scopus databases. This analysis provides a detailed overview of the field’s structure and development by examining trends in authorship, publication, keyword usage, journal impact, country contributions, and citation metrics. The findings reveal significant variability in journal productivity and impact, with the Journal of Chemical Education standing out as a dominant contributor. Keyword co-occurrence and centrality measures highlight the emphasis on practical, experiential learning and the field’s interdisciplinary nature. Country-level analysis underscores the central role of the United States, with substantial contributions from European and emerging Asian countries. The insights derived from this analysis suggest strategic directions for enhancing nanotechnology education programs including integrating hands-on learning, early education, and interdisciplinary collaborations. This study offers valuable guidance for researchers, educators, and policy makers who aim to advance the field of nanotechnology education.

Obtaining and analyzing fluorescence spectra is a valuable skill for students taking a course in enviro-analytical chemistry. This experiment allowed students to gain an understanding of metal complexation at varying pH using a fluorescence quenching technique. Students collected fluorescence spectra of BSA quenched by a range of Cu or Pb concentrations at two pH levels and conducted a Stern–Volmer analysis. Increasing the quenching agent concentration caused a decrease in the fluorescence intensity. Students recorded and plotted the fluorescence intensities at the peak maximum (F_max) against quenching agent concentration. The Stern–Volmer equation and modified Stern–Volmer equation were used to obtain complexation parameters: the Stern–Volmer constant of association (K_sv), the binding constant (K_a), and the stoichiometric coefficient of the metal (n). Copper demonstrated stronger binding with BSA at pH 5.1, while lead was a more effective quenching agent at pH 3.4. The degree of quenching decreased for both metals at pH 3.4, markedly more for Cu. This may be due to enhanced aggregation or unfolding of BSA at a lower pH, altering accessibility to binding sites. It may also be due to competitive binding with protons. Students were asked several questions related to their findings and to seek out additional research to support their ideas. Overall, students gained a molecular-level understanding of BSA–metal binding and the implications of protein conformation and denaturation at different pH levels. The questions were also used to prompt learning about environmental implications, including impacts of binding strength on the bioavailability of metal ions in the human body and aquatic systems.

The movement of gases through a polymer membrane is exemplified by the deflation of common latex balloons. This whimsical example provides a demonstration of the important interplay between kinetics and thermodynamics in determining the course of a process. Six balloons are filled with differing gases, and without prior knowledge, their behavior is difficult to predict. However, a discussion of partial pressures and well-established properties of gas diffusion through polymer films qualitatively explains the behavior, providing a clear example of a structure–property relationship.

A polarimeter constructed from off-the-shelf parts was used to measure the optical rotation of sugars as the central activity in a second-year online analytical chemistry laboratory course. Throughout the five-weeks of the course, students built the instrument and performed measurements of sugars at three different wavelengths. The kinetics for the mutarotation of glucose was measured, and its equilibrium constant was used to determine the optical rotatory dispersion of pure α- and β-d-glucose in solution, via linearization of Drude’s equation. This activity serves as a foundation of instrument construction and calibration, data analysis, and error propagation in optical measurements, while connecting concepts of introductory, organic, and physical chemistry in an experimental setting.

This Article aims to share the results of a project that was developed with 80 students from Technical High School of Professional and Technological Education (PTE) at an institute located in the northeast of Brazil. The students discussed the global overview of fuel production and use, and how the introduction of green hydrogen into the market can contribute to reducing the effects caused by climate change. Guided by the fundamentals of hands-on and it yourself, ideas linked to the movement of active methodologies and the Maker philosophy, this activity demands the students to be divided into teams to model and print hydrogen-powered vehicles on 3D printers. Methodologically, this paper presents itself as qualitative research, more specifically action research, and its data were analyzed through discursive textual analysis. Regarding its results, we can describe that (1) regarding the attitudinal aspect, the proposal was responsible for mobilizing and intensely involving students in carrying out the task; (2) in relation to scientific concepts, the data allow us to infer that the participants took ownership of the content that was worked on, such as chemical reactions, fuels, combustion reactions, use of chemical equations; but besides that, they presented an expanded theoretical repertoire in which they debated the topic covering aspects such as economic, political, technological, and in particular, environmental and climate change issues. These results allow us to infer that we are facing a successful proposal that promoted the engagement of students focused on the discussion of an environmental topic as relevant as new sources of energy to fight against climate change.

We have developed a set of multicolor 3D-printed structural and molecular orbital models for use in a first-semester organic chemistry course. These models provide visual and tactile insights regarding aspects of organic structure, reactivity, and mechanistic “arrow pushing”. The set includes: 1. orbital models of σ and π bonding in methane and ethylene, 2. σ_CH–σ*_CH hyperconjugation in staggered and eclipsed ethane conformations, 3. LUMO accessibility in S_N2 electrophiles and HOMO–LUMO orbital interactions in S_N2 transition states, 4. E2 transition state structure and orbital interactions in β-hydrogen removal and π bond formation, 5. σ_CH–p_C hyperconjugation in the ethyl cation, 6. transition state structure and σ_CH–p_C orbital interactions in a carbocation 1,2-hydride shift, 7. late and early, respectively, Br• and Cl• H atom radical abstraction transition state structures and SOMO orbitals, 8. bromonium ion structure and LUMO orbital, 9. protonated epoxide ion and neutral epoxide structures and LUMO orbitals, 10. transition state structure and orbital interactions in a hydroboration reaction, 11. transition state structure and orbital interactions in the lithium aluminum hydride reduction of formaldehyde, and 12. π molecular orbitals in 1,3-butadiene. The prints are made with hobby-grade 5-color 3D fused deposition modeling (FDM) printers and sized to provide compact take-home class handouts for each student or projected in-class with a document camera. Models are fabricated with orbital or electron density surface bisections and text annotations to enhance information content. Student perceptions of this set of 3D-printed molecular models are generally favorable and have improved their understanding of course materials.

Traditional assessment of practical work may depend on the examiner and may barely cover all learning objectives. To standardize the assessment of the practical work in pharmaceutical chemistry, an Objective Structured Practical Examination (OSPE) was developed and conducted among 142 fourth-year students of pharmacy. The evaluation included five stations that covered learning objectives studied during practical sessions. The scenarios involved drug identification through colorimetric reactions, thin-layer chromatography, and melting point measurement. Determination of the content of a sample, the calculation and the interpretation of a drug assay result, were also tested. The mean mark for the OSPE assessment was significantly lower compared to traditional assessment (15.02/20 ± 1.81 vs 15.82/20 ± 2.48, p < 0.001). However, a preliminary analysis shows that OSPE was preferred (56%), and that station 2, involving drug identification by thin layer chromatography, requires more time than the time allocated to each station (11 min). Despite the fact that it is time-consuming and needs many examiners, OSPE has been found to meet the teaching objectives of pharmaceutical chemistry practical work.