The purpose of this study was to elucidate and describe students’ thinking when making connections between substitution and elimination reactions and their corresponding reaction coordinate diagrams. Thirty-six students enrolled in organic chemistry II participated in individual, semi-structured interviews. Three major themes were identified that characterize students’ difficulties with integrating the information from the reactions and the reaction coordinate diagrams: incorrect ideas about the meanings of the reaction coordinate diagrams’ features, errors when examining reaction mechanisms, and an inability to assess the relative energies of reaction species. These findings suggest that students need support for coherence formation between reactions and reaction coordinate diagrams. Implications for teaching to address these student difficulties are suggested.

Organic chemistry students struggle with understanding the energetics of chemical reactions. Reaction coordinate diagrams are one tool that is widely used in organic chemistry classrooms to assist students with visualizing and explaining the energy changes that take place throughout a reaction. Thirty-six students enrolled in organic chemistry II participated in a qualitative study that used semi-structured interviews to investigate the extent to which students meaningfully extract and integrate information encoded in reaction coordinate diagrams. Results show that students have difficulties explaining the meanings of surface features such as peaks, valleys, peak height, and peak width. Analysis of students’ explanations resulted in four themes that describe students’ challenges with correctly interpreting the features of reaction coordinate diagrams. Students conflated transition states and intermediates, despite being able to recite definitions. Students described the chemical species encoded at points along thex-axis of the reaction coordinate diagrams, while largely ignoring the energies of the species encoded along they-axis. Implications for teaching organic chemistry are discussed.

The purpose of this study was to analyze organic chemistry students' annotations of reaction coordinate diagrams to better understand how they sought connections between reactions and reaction coordinate diagrams. Thirty-six students enrolled in Organic Chemistry II participated in semistructured, think-aloud interviews that asked students to choose a reaction coordinate diagram from a set of three possible diagrams to match a substitution reaction mechanism and then to match an elimination reaction mechanism. Students' annotations of the reaction coordinate diagrams provided in the interviews, and in some cases additional reaction coordinate diagrams generated by the students themselves, were examined. Qualitative analyses indicated that half of the participants considered only the "major" species (reactant, intermediate, and product) to be encoded in reaction coordinate diagrams, whereas the rest of the reaction species (leaving groups, nucleophiles/bases, and solvent molecules) were omitted from their drawings. These findings suggest that because organic chemists frequently write equations that are balanced neither in mass nor in charge, and because these equations tend to focus upon the formation of the major product, students can develop the idea that only the "major" chemical species are important to focus upon when interpreting the symbolic representations of reactions and reaction coordinate diagrams. The implications of these findings for classroom teaching are discussed.

In this review article, we analyze recent progress in the application of liquid crystal-assisted advanced functional materials for sensing biological and chemical analytes. Multiple research groups demonstrate substantial interest in liquid crystal (LC) sensing platforms, generating an increasing number of scientific articles. We review trends in implementing LC sensing techniques and identify common problems related to the stability and reliability of the sensing materials as well as to experimental set-ups. Finally, we suggest possible means of bridging scientific findings to viable and attractive LC sensor platforms.

Thirty-six students enrolled in Organic Chemistry II participated in individual, semistructured, think-aloud interviews about the factors that contribute to the stability and reactivity of organic species in the context of unimolecular and bimolecular nucleophilic substitution and elimination reactions. The students were provided with the mechanistic steps for these reactions. Most students correctly identified the leaving groups in these reactions and referred to them as “good leaving groups”. However, less than half of the students could explain the electronic and structural factors that justify characterizing a species as a “good” leaving group. Nearly one-third of the students who were interviewed were unable to provide any explanation of what factors result in a chemical species being a “good” leaving group. These findings are discussed through the lenses of both Perry’s scheme of intellectual development and Ausubel and Novak’s theory of meaningful learning.

The Reaction Coordinate Diagram Inventory (RCDI) has been developed to measure student thinking and confidence with reaction coordinate diagrams (RCDs) and their correspondence to reaction mechanisms. The RCDI was designed using a sequential mixed-methods protocol, such that the questions and distractors in the instrument were generated based on an analysis of qualitative semi-structured interviews in which general chemistry and organic chemistry students were asked to describe the concepts embedded in the surface features of RCDs and to use the mechanistic information encoded in RCDs. The RCDI was administered to second-semester general chemistry students (n = 443), second-semester organic chemistry students (n = 227), and second-semester physical/biophysical chemistry students (n = 45). Descriptive statistics and item function are presented for each of the three samples. Qualitative and quantitative evidence for the validity and reliability of the data generated by the RCDI are also presented. Major categories of misconceptions assessed by the RCDI and data demonstrating the prevalence of these misconceptions for all three groups of students are presented.

In this era of instructional transformation of Science, Technology, Engineering, and Mathematics (STEM) courses at the postsecondary level in the United States, the focus has been on educating science faculty about evidence-based instructional practices, i.e. practices that have been empirically proven to enhance student learning outcomes. The literature on professional development at the secondary level has demonstrated a tight interconnectedness between ones’ beliefs about teaching and learning and one's instructional practices and the need to attend to faculty's beliefs when engaging them in instructional change processes. Although discipline-based education researchers have made great strides in characterizing instructional practices of STEM faculty, much less attention has been given to understanding the beliefs of STEM about teaching and learning. Knowledge of instructors’ thinking can inform faculty professional development initiatives that encourage faculty to reflect on the beliefs that drive their classroom practices. Therefore, this study characterized the interplay between beliefs and instructional practices of nineteen assistant chemistry professors. Luft and Roehrig's Teaching Beliefs Interview protocol was used to capture beliefs; classroom observations and course artifacts were collected to capture practices. Clear trends were identified between faculty's beliefs (characterized through constant-comparative analysis and cluster analysis) and practices (characterized with Blumberg's Learner-Centered Teaching Rubric). Overall, beliefs of most of the participants were somewhat aligned with their instructional practices, with the exception of one cluster of faculty who held student-centered beliefs, but received only moderate scores on the Learner-Centered Teaching Rubric.

Representational competence is one's ability to use disciplinary representations for learning, communicating, and problem-solving. These skills are at the heart of engagement in scientific practices and were recognized by the ACS Examinations Institute as one of ten anchoring concepts. Despite the important role that representational competence plays in student success in chemistry and the considerable number of investigations into students’ ability to reason with representations, very few studies have examined chemistry instructors’ approaches toward developing student representational competence. This study interviewed thirteen chemistry instructors from eleven different universities across the US about their intentions to develop, teach, and assess student representational competence skills. We found that most instructors do not aim to help students develop any representational competence skills. At the same time, participants’ descriptions of their instructional and assessment practices revealed that, without realizing it, most are likely to teach and assess several representational competence skills in their courses. A closer examination of these skills revealed a focus on lower-level representational competence skills (e.g., the ability to interpret and generate representations) and a lack of a focus on higher-level meta-representational competence skills (e.g., the ability to describe affordances and limitations of representations). Finally, some instructors reported self-awareness about their lack of knowledge about effective teaching about representations and the majority expressed a desire for professional development opportunities to learn about differences in how experts and novices conceptualize representations, about evidence-based practices for teaching about representations, and about how to assess student mastery of representational competence skills. This study holds clear implications for informing chemistry instructors’ professional development initiatives. Such training needs to help instructors take cognizance of relevant theories of learning (e.g., constructivism, dual-coding theory, information processing model, Johnstone's triangle), and the key factors affecting students’ ability to reason with representations, as well as foster awareness of representational competence skills and how to support students in learning with representations.