Search Results (23)

In this work, we present the introductory methodology for a graphene field-effect transistor (GFET)-based platform for probing the electrochemical fingerprints of amino acids, designed to enable stable and controlled surface chemistry and electrochemical measurements toward peptide and protein sequencing. We begin with a focused conceptual review that motivates electrochemical fingerprinting as a strategy for amino acid and peptide identification and contextualizes this approach within recent advances in protein manipulation relevant to sequencing. We then describe a graphene functionalization protocol that facilitates the directional attachment of amino acids onto the graphene surface. This surface chemistry is quantitatively characterized through surface plasmon resonance (SPR), yielding surface densities in the order of 10¹² molecules/cm². The same functionalization protocol enables in situ peptide synthesis directly on graphene, as demonstrated by the successful synthesis of a model tripeptide. To support electrochemical interrogation, we developed three complementary platforms for sensor preconditioning, surface functionalization, and titration-based electrochemical measurements, compatible with both aqueous and organic solutions. Preliminary stability measurements indicate a Dirac point drift below 10 mV over 45 min. Altogether, this work establishes the experimental foundations for electrochemical amino acid and peptide fingerprinting using GFET sensors and provides a framework for the future development of electrochemically enabled protein sequencing technologies. Full article

Designing laboratory experiences that support both skill development and conceptual understanding is a persistent challenge in introductory chemistry education—especially within accelerated or compressed course formats. To address this need, we developed and implemented a systems-thinking-based laboratory module on error analysis for a large introductory chemistry course at Brown University, composed primarily of first-year students (approximately 150–200 students in the spring semesters). Unlike traditional labs that isolate single techniques or concepts, this module integrates calorimetry, precipitation reactions, vacuum filtration, and quantitative uncertainty analysis into a unified experiment. Students explore how procedural variables interact to affect experimental outcomes, promoting a holistic understanding of accuracy, precision, and uncertainty. The module is supported by multimedia pre-lab materials, including faculty-recorded lectures and interactive videos developed through Brown’s Undergraduate Teaching and Research Awards (UTRA) program. These resources prepare students for hands-on work while reinforcing key theoretical concepts. A mixed-methods assessment across four semesters (n > 600) demonstrated significant learning gains, particularly in students’ ability to analyze uncertainty and distinguish between accuracy and precision. Although confidence in applying significant figures slightly declined post-lab, this may reflect increased awareness of complexity rather than decreased understanding. This study highlights the educational value of integrating systems thinking into early-semester laboratory instruction. The module is accessible, cost-effective, and adaptable for a variety of institutional settings. Its design advances chemistry education by aligning foundational skill development with interdisciplinary thinking and real-world application. Full article

Undergraduate introductory chemistry is a gatekeeping course preventing students from persisting in STEM degree programs. It is important to understand students’ experiences of introductory chemistry and better support students as this course traditionally has high attrition and failure rates. This systematic literature review examines the factors of academic success for undergraduates in introductory chemistry courses and aims to understand how these factors differ for varying student groups. A meta-analysis of 35 articles uncovered three emergent themes for promoting students’ academic success: course design, instructional tools and resources, and student learning and characteristics. Most notably, active learning environments, metacognitive assessments, and student affective variables such as identity and motivation emerged as significant predictors of students’ academic success. Additionally, this review demonstrates how differences in student demographics, achievement levels, affective variables, and participation in chemistry affect the extent to which students succeed in this course. Student demographics were most frequently reported to cause disparities in course performance, with students from historically underrepresented populations exhibiting the most disadvantages in overall course performance. These findings signify the importance of creating effective learning environments in introductory chemistry for students from diverse backgrounds to achieve equitable outcomes and sustain STEM interest. Full article

In the U.S., the retention of students in STEM degree pathways has been an issue that many higher education institutions have and continue to face. Many of us in the chemistry education community have been reflecting on our own roles and responsibilities to create a more inclusive learning environment for all students in chemistry. Culturally relevant pedagogy (CRP) and culturally responsive teaching (CRT) are two influential frameworks that informed efforts in promoting inclusivity in chemistry classrooms. However, the current literature focuses primarily on isolated interventions, highlighting a need for theoretical development that articulates the synergy between the two frameworks and synthesizes them in the context of chemistry education. In this essay, we present a framework for re-envisioning chemistry classroom culture consisting of four tenets: culturally relevant chemistry knowledge, cultural validation, collectivist cultural orientations, and humanized chemistry learning environments. We identified five course redesign entry points: amplifying student voice, emphasizing group work, contextualizing content knowledge, scaffolding technical language, and revising assessment structures. We hope to present both a framework and a set of course redesign entry points for chemistry educators interested in re-envisioning their classroom culture. We will also discuss the evaluation plan of this project and future work to sustain student cultural assets in chemistry classrooms. Full article

Specifications and mastery grading schemes have been growing in popularity in higher education over the past several years, and reports of specifications grading and other alternative grading systems are emerging in the chemistry education literature. The general goal of these alternative grading approaches is to reduce the reliance on high-stakes exams and give students a more transparent pathway to achieving the course learning outcomes. More importantly, relying less on infrequent high-stakes exams may help reduce historical equity gaps in introductory gateway STEM courses. Herein, we describe the implementation of two versions of mastery grading systems in large enrollment general chemistry courses at a public R1 institution. Class-wide course outcomes, equity gaps in performance on a common final exam, and student feedback on their experience navigating these grading schemes are presented. We show that combining mastery grading with interactive courseware tools improved the average performance on a common final assessment for under-represented minority (URM) students by 7.1 percentage points relative to an active control course that used infrequent high-stakes exams. Full article

College-level introductory chemistry has a high impact for predicting students’ early success and long-term academic outcomes. Students from traditionally underserved communities are disproportionately held back in this course. To improve student success, the Supplemental Instruction (SI) program at a public four-year Hispanic-serving institution was revamped from a voluntary option to a co-requisite for the introductory chemistry course. The study evaluates the effectiveness of the new format of SI program and explores associated factors contributing to the impacts of the program. Students with or without SI were compared through multiple quantitative metrics, including course GPA, final exam score, DFW rate, and pass rate. Data analysis showed that students who completed SI with credit obtained 0.9 higher average course GPA than their counterparts and performed significantly better on all the other metrics. More importantly, the equity gaps between underserved and better-served students were narrowed down. Furthermore, students who took introductory chemistry with SI still obtained 0.3 higher average course GPA in their subsequent General Chemistry I course than those without it. The findings suggested that incorporating the SI into introductory chemistry as co-requisite is necessary and effective to improve students’ success and narrow down the equity gaps in gateway chemistry courses. Full article

After an introductory reminder of safety concerns pertaining to early rechargeable battery technologies, this review discusses current understandings and challenges of advanced sodium-ion batteries. Sodium-ion technology is now being marketed by industrial promoters who are advocating its workable capacity, as well as its use of readily accessible and cheaper key cell components. Often claimed to be safer than lithium-ion cells, currently only limited scientifically sound safety assessments of sodium-ion cells have been performed. However, the predicted sodium-ion development roadmap reveals that significant variants of sodium-ion batteries have entered or will potentially enter the market soon. With recent experiences of lithium-ion battery failures, sodium-ion battery safety management will constitute a key aspect of successful market penetration. As such, this review discusses the safety issues of sodium-ion batteries, presenting a twofold innovative perspective: (i) in terms of comparison with the parent lithium-ion technology making use of the same working principle and similar flammable non-aqueous solvent basis, and (ii) anticipating the arrival of innovative sub-chemistries at least partially inspired from successive generations of lithium-ion cells. The authors hope that the analysis provided will assist concerned stakeholders in the quest for safe marketing of sodium-ion batteries. Full article

When General Chemistry at West Point switched from interactive lectures to guided inquiry, it provided an opportunity to examine what was expected of students in classrooms and on assessments. Learning objectives and questions on mid-term exams for four semesters of General Chemistry I (two traditional semesters and two guided inquiry semesters) were analyzed by the Cognitive Process and Knowledge dimensions of Bloom’s revised taxonomy. The results of this comparison showed the learning objectives for the guided inquiry semesters had a higher proportion of Conceptual and Understand with a corresponding decrease of Factual, Procedural, Remember and Apply learning objectives. On mid-term exams, the proportion of Remember, Understand, Analyze/Evaluate, Factual, and Conceptual questions increased. We found that guided inquiry learning objectives and mid-term exam questions are more conceptual than traditional courses and may help explain how active learning improves equity in introductory chemistry. Full article

The concept of pseudocapacitance is explored as a rapid and universal method for the state of health (SOH) determination of batteries and supercapacitors. In contrast to this, the state of the art considers the degradation of a series of full charge/discharge cycles. Lithium-ion batteries, sodium-ion batteries and supercapacitors of different cell chemistries are studied by impedance spectroscopy during lifetime testing. Faradaic and capacitive charge storage are distinguished by the relationship between the stored electric charge and capacitance. Batteries with a flat voltage–charge curve are best suited for impedance spectroscopy. There is a slight loss in the linear correlation between the pseudocapacitance and Ah capacity in regions of overcharge and deep discharge. The correct calculation of quantities related to complex impedance and differential capacitance is outlined, which may also be useful as an introductory text and tutorial for newcomers to the field. Novel diagram types are proposed for the purpose of the instant performance and failure diagnosis of batteries and supercapacitors. Full article

Across a variety of fields, the use of low-stakes assessments has led to reductions in achievement gaps and improved student success. Here, we probe the use of a low-stakes assessment model with a retake option for failed quizzes in a two-semester general chemistry sequence. We find that the quiz-retake rate in general chemistry II was significantly higher for students who had completed a retake in a general chemistry I section, and the percentage of students who failed at least one quiz in general chemistry I but passed all quizzes in general chemistry II was significantly higher for students who had retaken at least one quiz in general chemistry I. However, across both semesters only 40% of students who failed a quiz and were offered a retake completed one. To examine this trend, we probed a connection to student attitudes and self-concept. As instruments, we used version 2 of the Attitudes towards Chemistry Subject Inventory (ASCIv2) and the Chemistry Subject Concept Inventory (CSCI), which were administered across all sections of our general chemistry I course in the fall 2021 semester, and the results subjected to confirmatory factor analysis. Two sections employed low-stakes assessments (quizzes), with one section offering a retake option, while the remaining two used a traditional assessment pattern of five exams. The instruments were applied again for the quiz-retake section of general chemistry II, affording a longitudinal comparison of students common to both sections. In a pairwise comparison, we find significant increases in factors corresponding to Intellectual Accessibility and Chemistry Self-Concept for students in the quiz-retake sections across semesters, with the former more pronounced for men and the latter for women. We take these results to provide additional data supporting the benefit of low-stakes assessments with a retake option, that may be particularly impactful for women in chemistry. Full article

We discuss the problematic terminology of “noncovalent interactions” as commonly applied to hydrogen bonds, rotation barriers, steric repulsions, and other stereoelectronic phenomena. Although categorization as “noncovalent” seems to justify classical-type pedagogical rationalizations, we show that these phenomena are irreducible corollaries of the same orbital-level conceptions of electronic covalency and resonance that govern all chemical bonding phenomena. Retention of such nomenclature is pedagogically misleading in supporting superficial dipole–dipole and related “simple, neat, and wrong” conceptions as well as perpetuating inappropriate bifurcation of the introductory chemistry curriculum into distinct “covalent” vs. “noncovalent” modules. If retained at all, the line of dichotomization between “covalent” and “noncovalent” interaction should be re-drawn beyond the range of quantal exchange effects (roughly, at the contact boundary of empirical van der Waals radii) to better unify the pedagogy of molecular and supramolecular bonding phenomena. Full article

Redox flow batteries (RFB) are considered one of the most promising electrochemical energy storage technologies for stationary storage applications, especially for long duration energy storage services. RFBs are electrochemical energy converters that use flowing media as or with active materials, where the electrochemical reactions can be reversed. Knowledge of technical standards and other regulations lay the foundations for successful and safe commercialization of products through uniform instructions and generally applicable rules. A small number of papers on safety and regulatory issues of RFBs are reported in the literature, mainly for two reasons. First, because this technology is considered safe; and second, because most of the publications have been limited to short-term characterization studies of materials in chemistry. This paper aims to help fill this gap, providing researchers and students with introductory knowledge on the safety and regulatory aspects of RFBs, mainly from an electrical and hydraulic point of view. The reader is referred to specific regulations for deeper studies and analyses. Full article

Spectroscopy is the basis of many applications in chemistry; however, the basic principles of light, light–matter interaction, and the operation of spectrophotometers are rarely present in chemistry curricula at the high-school level, or they are only briefly introduced to students before focusing on analytical chemistry applications. In this work, we report the results of a study conducted over several years, aimed to design, optimise, and put into practice a didactic sequence on light phenomena such as reflection, refraction, interference, diffraction, and light dispersion, as well as the basic principles of ultraviolet–visible spectroscopy and spectroscopic instruments. Difficult concepts of light phenomena and related topics were deeply investigated, focusing on the best ways to teach them to high-school students in the framework of the content-specific components identified in the topic-specific pedagogical content knowledge theoretical model. Inquiry-based learning and interactive STEM laboratory activities were combined with a historical epistemological teaching method. Short introductory videos were also recorded to help students during the remote lessons in the COVID-19 pandemic period. In this paper, we report and discuss the research strategy used in order to design and implement the sequence of educational activities, leading to a final optimised didactic sequence that was tested in a pilot study. The main results were obtained from the experimentation with several classes in two high-school technical institutes with a chemistry and material sciences curriculum, along with a group of undergraduate students during the first part of an introductory course on molecular spectroscopy. Full article

Incorporating real-life context through connections to research early in the curriculum can create meaningful learning opportunities that encourage students to engage deeply with classroom content to construct chemistry knowledge. Course-based undergraduate research experiences have been successful at integrating real-life context, but are often only incorporated into upper-level courses. To provide an additional pathway to foster interaction with research, four activities from an introductory chemistry discussion class were created to incorporate authentic research connections. Care was taken to incorporate metacognitive questions designed to help students make connections between their preexisting knowledge and course content. Marzano’s taxonomy was used to analyze the cognitive complexity of tasks, which increased in the revised activities, allowing for more opportunities for knowledge construction. Audio and written work of student groups as they worked through activities was collected. Qualitative analysis of student engagement revealed that control over the content of activities to incorporate opportunities for knowledge construction is not enough to facilitate students consciously engaging in meaningful learning. If instructors wish to promote students integrating chemistry knowledge into their existing framework, course instructors, including graduate teaching assistants, need to be trained on how to properly facilitate classroom experiences to increase the likelihood of success. Full article

In this essay the origins of the term hypervalence and its application in p-block element chemistry are considered and it is argued that the term should now be consigned to the graveyard of concepts that no longer afford any discernible value or insight, certainly from an educational perspective. In contrast, the educational merits of the octet rule are also examined where it is concluded that this rule does have significant pedagogical value, albeit mostly within the ambit of introductory level explanations. For a few of the chosen exemplar compounds, a selection of orbital-based analyses, at different levels of sophistication, are also considered, and their values appraised together with a brief survey of some of the more general computational studies which have been employed in relation to this topic. Full article