Showing papers in "Journal of Chemical Education in 2010"

ChemSpider:: An Online Chemical Information Resource

Abstract: ChemSpider is a free, online chemical database offering access to physical and chemical properties, molecular structure, spectral data, synthetic methods, safety information, and nomenclature for almost 25 million unique chemical compounds sourced and linked to almost 400 separate data sources on the Web. ChemSpider is quickly becoming the primary chemistry Internet portal and it can be very useful for both chemical teaching and research.

A Graphical Journey of Innovative Organic Architectures That Have Improved Our Lives

Abstract: A new free graphical teaching tool that highlights the beautiful organic architectures of the top selling pharmaceuticals is detailed on two posters. In addition to the multitude of teaching and data-mining opportunities these posters offer, they were also created to emphasize the central role organic chemists play in the development of new therapeutics.

How Long Can Students Pay Attention in Class? A Study of Student Attention Decline Using Clickers

Abstract: Students enrolled in three levels of general chemistry self-reported their attention decline during both lecture and other teaching approaches via personal response devices (clickers). Students report attention declines of 1 min or less more often than longer attention lapses. The data suggest that student engagement alternates between attention and nonattention in shorter and shorter cycles as lecture proceeds. Introduction of other pedagogies, specifically, clicker questions and demonstrations resulted in significantly lower self-reported student attention decline than lecture. This effect persisted during lectures immediately following the intervening pedagogies. Implications of this research for teaching are discussed.

Contact Angle Measurements Using a Simplified Experimental Setup

Abstract: A basic and affordable experimental apparatus is described that measures the static contact angle of a liquid drop in contact with a solid. The image of the drop is made with a simple digital camera by taking a picture that is magnified by an optical lens. The profile of the drop is then processed with ImageJ free software. The ImageJ contact angle plugin detects the edge of the drop and fits its profile to a circle or an ellipse. The tangent to the triple line contact is calculated and drawn by the ImageJ software, thus, returning the value of the contact angle with acute precision on the measurement.

You Can’t Get There from Here1

Abstract: Large curricular changes of the 1960s brought about by the ChemStudy and Chemical Bond Approach initiatives were generally successful, but they also created learning problems. These were well recognized by a series of surveys in 1971. Recent surveys (2008) show that the same chemical difficulties for learners are still present in most “modern” curricula at all levels. This is despite the efforts of many international research projects designed to improve the learning of chemistry. The common factor in all these problem areas for chemistry students is information overload. The effect of having these problematic topics in the curriculum is to drive students away from chemistry. We have come to accept that these topics are fundamental to learning chemistry, but are they so essential? Are we blindly teaching them because they have “always been taught”? This paper suggests a bold approach, which questions the inclusion of these problematic topics and suggests models by which a pragmatic revision can take place...

Lost in Lewis Structures: An Investigation of Student Difficulties in Developing Representational Competence

Abstract: Because Lewis structures provide a direct connection between molecular structure and properties, the ability to construct and use them is an integral component of many chemistry courses. Although a great deal of time and effort has been dedicated to development of “foolproof” rules, students still have problems with the skill. What is more, many students fail to connect the skill with the reasons for learning it. In fact, it appears that conventional instructional practices involved in teaching Lewis structures are in direct conflict with much of what we know about how people learn. In support of this assertion, we present the results of a mixed-methods study designed to investigate how students at all levels draw Lewis structures, and how students perceive the utility of Lewis structures. We offer suggestions for alternative methods of developing this skill in order to provide students with an approach to meaningful learning.

Surface Plasmon Resonance: An Introduction to a Surface Spectroscopy Technique.

Abstract: Surface plasmon resonance (SPR) has become an important optical biosensing technology in the areas of biochemistry, biology, and medical sciences because of its real-time, label-free, and noninvasive nature. The high cost of commercial devices and consumables has prevented SPR from being introduced in the undergraduate laboratory. Here, we present an affordable homemade SPR device with all of its components accessible to visualization. This design allows ease of integration with electrochemistry and makes the device suitable for education. We describe a laboratory experiment in which students examine the relationship between the SPR angle and the solution refractive index at the interface and perform a coupled SPR−electrochemistry experiment. Students also study the antibody−antigen binding activity. Most of the experimental work was done as a project by a grade 12 high-school student under proper supervision. We believe that the SPR device and the SPR laboratory will enhance undergraduate chemical education by introducing students to this important modern instrumentation and will help students to learn and understand the molecular interactions occurring at interfaces.

Faculty Perspectives of Undergraduate Chemistry Laboratory:: Goals and Obstacles to Success

Abstract: Faculty perspectives of the undergraduate chemistry laboratory were the focus of a study to articulate the goals, strategies, and assessments used in undergraduate teaching laboratories. Data were collected via semistructured interviews with faculty (N = 22) from community colleges, liberal arts colleges, comprehensive universities, and research institutions engaged in teaching or supervising undergraduate laboratories. The goals for general chemistry, organic chemistry, and upper-division laboratories are described and compared among faculty who have received NSF-CCLI (now called NSF-TUES) grants to implement changes in laboratory and those who have not. Problems and limitations to success in laboratory are also reported, and the impact of these obstacles on student achievement and laboratory curricula is discussed.

Synthesis of Silver Nanoprisms with Variable Size and Investigation of Their Optical Properties: A First-Year Undergraduate Experiment Exploring Plasmonic Nanoparticles

Abstract: A robust and reasonably simple experiment is described that introduces students to the visualization of nanoscale properties and is intended for a first-year laboratory. Silver nanoprisms (NPs) that display different colors due to variation of their plasmonic absorption with respect to size are prepared. Control over the size of the silver nanoprisms is achieved using a novel approach, where bromide is added to the reaction as a size-determining agent, and silver ions are reduced by borohydride in the presence of citrate and peroxide as stabilizing and shape-directing agents, respectively. In a typical experiment, four dispersions of silver nanoprisms with different sizes are produced that are colored from blue (largest) to yellow (smallest). The colors attainable in between are violet, purple, red, and orange. The synthesis of these colored silver NPs is described for the first time as an undergraduate experiment. Once synthesized, the nanoprisms are characterized using UV−vis spectroscopy, and a Beer’s ...

Identifying Alternative Conceptions of Chemical Kinetics among Secondary School and Undergraduate Students in Turkey.

Abstract: This study identifies some alternative conceptions of chemical kinetics held by secondary school and undergraduate students (N = 191) in Turkey. Undergraduate students who participated are studying to become chemistry teachers when they graduate. Students’ conceptions about chemical kinetics were elicited through a series of written tasks and individual interviews. Several alternative conceptions exhibited by secondary school students persisted among undergraduates, indicating the persistence of such alternative conceptions. The results suggest that students’ lack of understanding in thermodynamics and chemical equilibrium significantly influences their conceptions about chemical kinetics. Implications for instructional approaches particular to chemical kinetics are discussed.

Improving Science Education and Understanding through Editing Wikipedia

Abstract: This paper describes a graduate-level class project centered on editing chemistry-related entries in Wikipedia. This project enables students to work collaboratively, explore advanced concepts in chemistry, and learn how to communicate science to a diverse audience, including the general public. The format and structure of the project is outlined and assessment metrics are discussed. A panel survey of current students provided an evaluation of the effectiveness of this project in contributing to the learning objectives of the course. Last, a discussion of the challenges involved in implementing this project is provided.

Classifying End-of-Chapter Questions and Problems for Selected General Chemistry Textbooks Used in the United States

Abstract: Science textbooks have a major influence on teaching and learning. Teachers and instructors at all educational levels use them regularly not only as a guide for course content and sequence but also in the design of homework assignments and assessment probes. From this perspective, textbook questions and problems can be expected to have a strong influence on assessment practices in the science classroom. Thus, the main goal of this study was to investigate the nature of end-of-chapter questions and problems included in college general chemistry textbooks and discuss the implications of this analysis for teaching and learning in introductory chemistry courses. Our results indicate that commonly used general chemistry textbooks include a majority of questions and problems at the “Application” and “Analysis” levels as defined using Bloom’s cognitive categories. These items tend to be narrowly focused on certain specific types. For example, problems at the “Application” level are mainly algorithmic, while ques...

The Case for Reform of the Undergraduate General Chemistry Curriculum

Abstract: This month, the National ACS meeting in San Francisco offers chemistry educators the opportunity to meet and discuss the important issues of our field. One topic that is ripe for debate is general chemistry, its role in the curriculum, and how (or even if) it should be changed so that students acquire a robust and relevant understanding of chemical principles. General chemistry is the college course in which most students begin and end their chemistry studies. While required in a wide range of degree programs, including engineering and sciences, it would be fair to say that most students and many faculty find the course to be less than satisfactory, and there have been numerous calls for reform (1-4). Those involved mainly agree that the way general chemistry is typically taught engenders several problems. Specifically, general chemistry: • Covers too much material, thereby sacrificing depth for breadth • Is taught as if students were chemistry majors, ignoring the fact that most students are not • Takes approaches that are generally ineffective at encouraging student understanding of basic concepts, regardless of whether those students are chemistry majors • Uses a course or curricular design inconsistent with both the realities and the research on how students learn • Is not usually taught in a pedagogically sound (that is, effective) manner • Often fails to engage student interest: some studies indicate (5) that students emerge from general chemistry courses with a lessexpert concept of what chemistry is and a lower satisfaction with chemistry than when they began The current incarnation of general chemistry has its roots in the 1960s as a response to the perceived need for a more robust and rigorous technical education. In an attempt to provide a theoretical basis for what was seen as a largely descriptive course, a more mathematical and theoretical curriculum was developed, largely through the addition of topics from physical chemistry (6). The resulting curriculum is the one we see today, with a few exceptions. Over time, new content has been added to the general chemistry course. For example, texts from the early 1960s generally do not mention entropy, free energy, or molecular orbitals, but today's textbooks do. At the same time, little content has been removed. The texts of today are larger and more encyclopedic than ever, so that the typical course often appears to the novice as a disjointed, brisk trot through a host of unrelated topics. One common response from students interviewed as to what they remember from general chemistry is that they detected no overarching principles or themes. While strong networks of faculty have implemented reformed, interactive pedagogies such as process-oriented, guidedinquiry learning (POGIL), peer-led team learning (PLTL), the use of clickers, and problem-based learning (7), the underlying content and overall structure of most general chemistry courses have changed little over the last 40 years. This is despite the often-dramatic changes in the needs of the students required to take the course. For example, general biology has shifted from being a largely descriptive course to one that provides an organizing conceptual framework based on physiochemical principles. Engineers increasingly work at the nanolevel, where an understanding of how and why molecular structure affects the function of materials is critical. For such students, general chemistry's traditional focus on stoichiometric calculations and the gas laws is too often irrelevant. Even chemistry majors need a robust understanding of fundamental chemical principles. We should provide this, but often do not. A number of looming changes may force us to become more reflective about how and what we teach. In the future it is unlikely that we will be able to “count on” a captive audience of general chemistry students (and organic chemistry students, for that matter). Most large chemistry departments depend heavily on the general and organic chemistry courses to support the departmental operations and funding for the TA budget. Accrediting agencies and professional schools are increasingly requiring outcomes-based assessments of competencies. In other words, students may be able to demonstrate a skill or understanding of a concept without being required to take a course in that subject. The scarcity of discretionary credit hours in every curriculum may make two (or four) semesters of chemistry a thing of the past. We have to become more responsive to the needs of our students or risk becoming obsolete (at worst) or marginalized, at best. Over the years, many initiatives have aimed to change general chemistry. Some have produced exemplary materials and improved outcomes, but none have brought about the type of systemic reform that might be hoped for. Why is this? Why, after millions of dollars and the efforts of hundreds of curriculum developers, researchers, publishers, and teachers of chemistry, is general chemistry still such a problematic course? Why is there such resistance to change? It is not as if the design of the course were intentionally well crafted in the first place. Alex H. Johnstone, winner of the 2009 ACS Award for Achievement in Research for the Teaching and Learning of Chemistry (6), points out that we have been teaching our current version of the general chemistry course for so long that we have forgotten why, for example, Chapter 4 is always solutions (if there ever were a reason) or why the coverage of gases comes before a discussion of entropy. The reason mainstream textbooks all look more or less the same (except for some chapter juggling) is not because publishers are content with the status quo but rather because they provide the texts instructors believe they want. We have only ourselves to blame. The ACS Committee on Professional Training has had relatively little to say about general chemistry. This is because the committee is more concerned with the education of professional chemists, despite the fact that building on a weak foundation is not the generally accepted approach to building a strong structure. It is time, however, for ACS to take a clear stand on what a general chemistry curriculum should entail, both in terms of content mastery and demonstrable skills. The ACS's Society Committee on Education has voted to convene a task force (made up of representatives from areas whose students take general chemistry, curriculum developers, chemical education researchers, and publishers) to investigate the possibility of developing a set of ACS standards for general chemistry courses. These new standards would articulate a set of concepts central to the understanding of chemistry and common to any general chemistry course. Rather than serving as a laundry list of topics to be taught (like many state standards), the new standards would provide a clearly argued focus on the foundational ideas and skills that we as chemists agree are central to fluency in general chemistry. We might hope that such standards will have far-reaching effects, including promoting interest in chemistry as a career, increasing student understanding and appreciation of key chemical concepts, and providing a focus for curriculum developers, publishers, and researchers.1 Extracting the important concepts from the mishmash that comprises the traditional general chemistry course would provide support and focus for a range of activities, including assessment (e.g., the ACS Examinations Institute), text adoption, and support for innovative curriculum development. What is the alternative? Just this: we can sit and wait for our own obsolescence three “big ideas”: The structure of matter; matter and change; and energy and change. Each standard has three to six objectives, each of which articulates essential knowledge needed to understand a particular concept. What differentiates these standards from others is that each objective is accompanied by performance expectations, i.e., what students should know and be able to do with that knowledge.

Safety Teams: An Approach to Engage Students in Laboratory Safety.

Abstract: We developed and implemented a yearlong safety program into our organic chemistry lab courses that aims to enhance student attitudes toward safety and to ensure students learn to recognize, demonstrate, and assess safe laboratory practices. This active, collaborative program involves the use of student “safety teams” and includes hands-on safety training as well as student-led safety presentations, laboratory monitoring, and postlab inspections for each lab session. Although we implemented this program in organic chemistry, one asset of this approach is its portability; it could easily be appropriately modified and implemented in nearly any science laboratory course. This article describes safety teams in detail and provides a preliminary assessment of the program’s effectiveness.

Education for a Sustainable Future

Abstract: The first green revolution began in the 1940s with the transformation of agricultural practices. Widespread use of pesticides, fertilizers, and irrigation techniques, coupled with the development of new, high-yielding crop varieties, dramatically increased food production. The green revolution enabled worldwide food production to keep pace with the rapidly expanding population of the globe. Like most revolutions, however, there were consequences. Energy inputs increased, fertilizer use resulted in eutrophication of bodies of water, and some pesticides affected nontarget organisms and persisted in the environment. Nonetheless, the widespread implementation of modern agricultural practices reduced famine in many countries, such as India and Pakistan. We are currently experiencing the second green revolution and are bombarded with green messages in the media. Green buildings, green dry cleaning, green fuels, and even green weddings: the message that we need to be aware of the impact of our actions on the environment is inescapable. (Recently, one television network even touted “green dramas” and “green comedies”!) Making environmentally responsible choices lets us contribute as individuals to the sustainability of our planet. As chemists, we can also contribute to sustainability. Our discipline's unique contribution to sustainability is green chemistry. By designing chemical products and processes that are better for both the environment and human health, chemists can provide society with the goods and services on which it depends in a way that uses Earth's resources more responsibly than before and with an eye toward the needs of future generations. Green chemistry is not a field solely under the purview of green chemists: It is an approach that is applicable to all areas of chemistry, and it is the responsibility of all practicing chemists. Chemistry is essential to sustainability: chemists and engineers have the knowledge and skills necessary to transform the chemical industry into one that is cleaner and greener. Where does chemical education fit into the current green revolution? We must do a better job of educating our students with respect to green chemistry, sustainability, and environmental issues. The Organisation for Economic Co-operation and Development (OECD) report Green at Fifteen? How 15- Year-Olds Perform in Environmental Science and Geoscience in PISA (the Programme for International Student Assessment) (1) indicates that while a majority of students are aware of environmental issues, their understanding of the underlying causes of these issues lags behind their awareness. U.S. students scored below the average on this OECD assessment. Sustainability education is so important that the United Nations declared the years 2005 through 2014 the “Decade of Education for Sustainable Development”. The goal of this decade is “to integrate the principles, values, and practices of sustainable development into all aspects of education and learning, in order to address the social, economic, cultural, and environmental problems we face in the 21st century” (2). Teaching chemistry in the context of the principles, values, and practices of sustainable development will enable our students to design environmentally beneficial products and processes as professional chemists and make informed choices as consumers and voters. As curricular topics, green chemistry and sustainability tend to be relegated to the margins of textbooks or confined to specialized courses. Perhaps we should inaugurate a third green revolution, one that will focus on education, to ensure that all students are well versed in environmental problems and potential solutions. A commitment to green education would produce an informed global citizenry and create a cadre of environmentally savvy scientists and engineers. Safe drinking water, alternative energy sources, and sustainable agricultural practices will be realized only by building an educated and innovative workforce. The first and second green revolutions are embedded in this year's Chemists Celebrate Earth Day theme of Plants: The Green Machines. Plants are the ultimate chemical factories, using sunlight to transform carbon dioxide and water into glucose and oxygen. It is hard to find a “greener” reaction than photosynthesis! And the sun is the ultimate energy source for our planet, providing the energy to grow plants that feed both people and animals. Too many people equate chemistry with harming the planet. Earth Day provides us with an occasion to emphasize the positive contributions of chemistry to human health and the environment. As we mark the 40th anniversary of Earth Day, please take this opportunity to highlight both the role of chemistry in securing the future of our planet and the part that chemical educators will play in making this happen. The vision of the American Chemical Society is “improving people's lives through the transforming power of chemistry”. Lifesaving drugs and revolutionary new materials are but two examples of chemistry's ability to improve people's lives. These breakthroughs were made possible through education, the foundation upon which our sustainable future will be built.

Developing Learning Objectives and Assessment Plans at a Variety of Institutions: Examples and Case Studies

Abstract: Across the United States many chemistry departments are engaged in developing assessment plans. New guidelines from the American Chemical Society (ACS) Committee on Professional Training request a department’s latest self-assessment and a plan for acting on the recommendations. This manuscript describes assessment practices at institutions ranging in type from large public state institutions to small private liberal arts colleges. These practices are fit into a model of iterative cycles of assessment with the ultimate goal of providing data that can be used to improve courses and programs. The examples and case studies described herein can be used as models for adaptation or background information for the formulation of learning objectives and assessment plans. The contributions of the ACS Examinations Institute through its suite of examinations, including the Diagnostic for Undergraduate Chemical Knowledge, is also cited as an important element in helping departments develop their assessment plans

Peer-Led Team Learning: 2008 James Flack Norris Award Address

Abstract: This paper offers an overview of the development of the peer-led team learning (PLTL) model for teaching and learning chemistry, from the personal journeys of the authors in their classrooms to the national dissemination of the model to the full range of colleges and universities and to other STEM disciplines. In the PLTL model, students who have done well in the course serve as peer-leaders to facilitate Workshops that supplement the lecture part of the course for new students. In the weekly Workshops, 6−8 students engage in active debate, discussion, and problem solving under the guidance of the peer leaders. A diverse faculty team led the development of instructional materials for the Workshops, methods to train peer leaders, and tactics to institutionalize PLTL. Students and leaders value the peer-led Workshops, and results from within the PLTL project (as well as numerous independent studies) demonstrate significant gains in student learning for both groups. PLTL remains an active area of research an...

Student Interpretations of Equations Related to the First Law of Thermodynamics

Abstract: Student interpretations of the equation for the first law of thermodynamics, ΔU = q + w, an expression defining work done on or by a gas, w = −∫PdV, and an expression defining heat, q = ∫CvdT were investigated through a multiple-choice survey, a free-response written survey, and interviews. The students examined had completed an undergraduate physical chemistry class in which they studied thermodynamics extensively and used these equations frequently to solve problems. The survey and interview results suggest that many students were unable to distinguish the concepts represented in the first law equation from concepts represented in the equations for work and heat. Students expressed a variety of physical interpretations for these fundamental equations. Some common misinterpretations were identified. These results suggest that far more attention needs to be placed on helping students learn the physical meaning of equations in thermodynamics courses.

Using Molecular Representations To Aid Student Understanding of Stereochemical Concepts

Abstract: Stereochemistry is an important topic in organic chemistry. It is also a difficult topic for students to learn. This study investigated the relative effectiveness on students’ understanding of three kinds of molecular representations of stereochemistry concepts. Instructional activities compared the use of either: (i) computer-based molecular visualization software; (ii) handheld ball and stick models; or (iii) two-dimensional perspective drawings to represent stereochemical structures. Results showed that computer visualization software could be an effective tool for teaching stereochemistry.

An Analysis of Undergraduate General Chemistry Students’ Misconceptions of the Submicroscopic Level of Precipitation Reactions

Abstract: This study examined how 21 college-level general chemistry students, who had received instruction that emphasized the symbolic level of ionic equations, explained their submicroscopic-level understanding of precipitation reactions. Students’ explanations expressed through drawings and semistructured interviews revealed the nature of the misconceptions that they held. These misconceptions and recommendations for instructional changes to target the misconceptions are examined in this article.

Fundamentals of Atom Transfer Radical Polymerization

Abstract: Today’s market increasingly demands sophisticated materials for advanced technologies and high-value applications, such as nanocomposites, optoelectronic, or biomedical materials. Therefore, the demand for well-defined polymers with very specific molecular architecture and properties increases. Until recently, these kinds of polymers could only be prepared via living ionic polymerization, a process that requires very stringent experimental conditions. Recently, atom transfer radical polymerization (ATRP), a controlled/living radical polymerization (CRP) process, has emerged as a viable alternative. ATRP allows the synthesis of polymeric structures that are well-defined in terms of composition and molecular architecture. By virtue of its simplicity, versatility and scope to make polymers with site-specific functionality and novel architecture, ATRP has become the most extensively studied CRP technique.

Art, Meet Chemistry; Chemistry, Meet Art: Case Studies, Current Literature, and Instrumental Methods Combined To Create a Hands-On Experience for Nonmajors and Instrumental Analysis Students

Abstract: Case studies and current literature are combined with spectroscopic analysis to provide a unique chemistry experience for art history students and to provide a unique inquiry-based laboratory experiment for analytical chemistry students. The XRF analysis method was used to demonstrate to nonscience majors (art history students) a powerful application of chemistry. Spectroscopy was used in the examination of a painting to determine the chemical components of the pigments used. In addition to demonstrating the XRF methods to art history students, chemistry students in instrumental analysis used spectroscopy, including XRF, to examine both the chemical composition of the paints used as well as the presence of an underpainting.

Developing Technical Writing Skills in the Physical Chemistry Laboratory:: A Progressive Approach Employing Peer Review

Abstract: Writing formal “journal-style” lab reports is often one of the requirements chemistry and biochemistry students encounter in the physical chemistry laboratory. Helping students improve their technical writing skills is the primary reason this type of writing is a requirement in the physical chemistry laboratory. Developing these skills is an important goal, yet sometimes students are not given enough time to review and revise their writing. Further, they seldom are taught how to review, and thus critical steps in the writing process are omitted. We have developed an approach with the goal of helping students improve their technical writing skills that employs the peer-review process and includes detailed guidance for writing reports in a progressive manner. We present these assignments, how student progress is assessed, and how the components fit to improve the technical writing abilities of the students.

Straw Men and False Dichotomies: Overcoming Philosophical Confusion in Chemical Education.

Abstract: Constructivism has been widely considered the most influential perspective in science education research for some decades, and has been the basis of widespread pedagogic advice in many educational contexts. Yet it has been claimed in this Journal that the philosophical basis of constructivist thought in chemical education is confused, and strongly associated with antiscientific thinking that is completely inconsistent with the working assumptions of professional chemists. It has been argued that constructivist pedagogy is inherently tied to the dangerous assumption that as all ideas are human constructions, there is no basis for preferring accepted scientific models to students’ own alternative ideas. The present paper demonstrates that the constructivist position criticized in this Journal is a complete misrepresentation of mainstream constructivist thinking in science education. Furthermore, it is argued that the claim of philosophical confusion rests upon a false dichotomy between realism and relativism, whereas the actual philosophical position underpinning mainstream constructivism in chemical education is instrumentalism, which is not only consistent with the approach of many scientists, but offers a promising basis for challenging many difficulties students have in learning the subject.

Green, Enzymatic Syntheses of Divanillin and Diapocynin for the Organic, Biochemistry, or Advanced General Chemistry Laboratory

Abstract: Environmentally benign chemistry is an increasingly important topic both in the classroom and the laboratory. In this experiment, students synthesize divanillin from vanillin or diapocynin from apocynin, using horseradish peroxidase and hydrogen peroxide in water. The dimerized products form rapidly at ambient temperature and are isolated by filtration. The products are readily distinguished from starting materials by solubility, NMR spectroscopy, or melting point analysis. The experiment is adaptable to an organic chemistry course in the context of radical reactions of phenols, to a biochemistry course in the context of metalloenzymes, or to an advanced general chemistry course in the context of green chemistry.

Ionic liquids and green chemistry : a lab experiment

Abstract: Although ionic liquids have been investigated as solvents for many applications and are starting to be used in industrial processes, only a few lab experiments are available to introduce students to these materials. Ionic liquids have been discussed in the context of green chemistry, but few investigations have actually assessed the degree of their greenness. This experiment combines two research areas, ionic liquids and ecological assessment, in an advanced undergraduate lab course. The modular combination of these two research areas allows for the adaptation of the timetable and content. Two ionic liquids are synthesized, and the method of heating (microwave-assisted vs convective), temperature, time, and alkylating agent are varied. In addition to the yield, simple metrics (atom economy, reaction mass efficiency, E-factor) in combination with energy efficiency, prices of chemicals, and ecological impacts of the materials are considered. It is the goal of this experiment to help students realize that a ...

Fusion Science Theater Presents The Amazing Chemical Circus:: A New Model of Outreach That Uses Theater To Engage Children in Learning

Abstract: Demonstration shows are a popular form of chemical education outreach used to increase interest, engagement, and appreciation of chemistry. Although practitioners often include instructional elements, evaluation has been limited to children’s attitudes toward science rather than their understanding of the underlying concepts presented. In 2006, we developed an interdisciplinary demonstration show that used elements from theater to engage children’s minds, emotions, imaginations, and bodies in the act of learning. The result was The Amazing Chemical Circus, a show that laid the groundwork for a new model of science education outreach that we call Fusion Science Theater. Assessments of learning following presentations of The Amazing Chemical Circus indicate significant gains in children’s conceptual knowledge as well as their attitudes toward science. In this article, we draw parallels between scientific investigation and theatrical practices that reveal common underlying principles at work. We also report ...

The Full Story of the Electron Configurations of the Transition Elements

Abstract: The dominant electronic valence configurations of atoms in chemical substances of a transition element of group G in period n is (n − 1)dGns0. Transition-metal chemistry is d orbital chemistry. In contrast, the ground states of free, unbound atoms derive, in most cases, from configurations (n − 1)dG−1ns1 or (n − 1)dG−2ns2. Five features must be considered to resolve this paradox. Point (i), the d−s orbital−energy distance in relation to the averaged differences of dd, ds, and ss two-electron repulsion energies, has often been discussed in the literature. However, four equally important features are (ii) the different two-electron repulsion energies within the d shell; (iii) the spin−orbit coupling energies in the d shell;and, in particular, (iv) the “d-orbital collapse” below the s level for increasing nuclear charge around group 3 and (v) the different perturbations of the valence (n − 1)d and ns orbitals when a free atom enters an alloy or compound. There is a conceptual difference between spectroscopic...

Measuring Vitamin C Content of Commercial Orange Juice Using a Pencil Lead Electrode

Abstract: A pencil lead successfully served as an electrode for the determination of ascorbic acid in commercial orange juice. Cyclic voltammetry was used as an electrochemical probe to measure the current produced from the oxidation of ascorbic acid with a variety of electrodes. The data demonstrate that the less expensive pencil lead electrode gives results that are comparable to those of a more expensive commercial carbon electrode. The level of vitamin C measured was higher than the daily intake recommended by Health Canada and the United States Food and Drug Administration, which is 60 mg/day for a healthy adult. The detection limit of the pencil lead electrode was also determined.

Is the Academic Climate Chilly? The Views of Women Academic Chemists.

Abstract: The statistical picture of the gender composition of chemistry as reported in national data indicates that women are underrepresented in academe in comparison to their representation in the field as a whole. This article presents data on the perceptions and views of a broad cross-section of women in academic chemistry departments and provides some clues as to why this underrepresentation may occur. In general, the data support literature that has posited a work climate that is problematic and less than welcoming for women. The results indicate that a large proportion of the women surveyed report that they receive little professional support through mentoring, that they perceive that there are strong differences in the resources and privileges awarded to men and women faculty, and that gender-related issues affect their department’s ability to recruit and hire or to promote women’s career progress after they are hired. Finally, the chemistry women in this study were significantly less likely than those in ...