Showing papers in "Journal of Chemical Education in 2006"
TL;DR: The unlikely events surrounding the discovery of its anticancer activity, subsequent introduction into the clinic, and the continuing research into platinum compounds is the subject of this review.
Abstract: Cisplatin is currently one of the most widely used anticancer drugs in the world. The unlikely events surrounding the discovery of its anticancer activity, subsequent introduction into the clinic, and the continuing research into platinum compounds is the subject of this review. Cisplatin and related platinum compounds remain the focus of extensive research. Reliable methods for the synthesis of such compounds have been developed and it has been established that they exert their anticancer activity through interaction with DNA. The search continues for a platinum drug to improve upon the clinical performance of cisplatin. Several have entered clinical trials but have been abandoned for a variety of reasons. However, preliminary results on novel compounds have been particularly promising.
421 citations
TL;DR: In this paper, the electron paramagnetic resonance (EPR) spectroscopy was used for the characterization of the geometry and electronic structure of the copper complexes, and three common ligands, ethylenediamine (en), 1,10-phenanthroline (phen), and 2,2′-bipyridine (bpy), were used.
Abstract: An instrumental experiment is presented in which eleven Cu(II) complexes are studied with electron paramagnetic resonance (EPR) spectroscopy. The EPR spectroscopy allows the characterization of the geometry and electronic structure of the copper complexes. Three common ligands, ethylenediamine (en), 1,10-phenanthroline (phen), and 2,2′-bipyridine (bpy), were used. Examination of the EPR spectra of the solid-state compounds demonstrates that [Cu(en)2(ClO4)2], [Cu(en)2(BF4)2], and [Cu(en)2(NO3)2] have a dx2-y2 ground state and an elongated octahedral geometry; that [Cu(phen)2(H2O)](NO3)2, [Cu(phen)2(H2O)](BF4)2, and [Cu(bpy)2Cl]ClO4 are characterized by a geometry intermediate between the square pyramid and the trigonal bipyramid and a ground state corresponding to the linear combination of the dx2-y2 and dz2 orbitals; and that [Cu(phen)2Cl]ClO4, [Cu(phen)2Br]ClO4, [Cu(bpy)2Br]ClO4, [Cu(phen)2]ClO4, and [Cu(bpy)2I]ClO show a geometry close to the trigonal bipyramid and a ground state of dz2. A theoretical e...
290 citations
TL;DR: This article found that many students' conceptual difficulties result from commonsense reasoning, which is based upon a set of assumptions about the natural world and the application of reasoning heuristics that students instinctively follow and apply without hesitating or considering other alternatives.
Abstract: Students' alternative conceptions play a central role in how they learn science. However, the large number and diversity of these alternative conceptions makes it difficult for teachers to identify any patterns in their students' thinking. A thorough analysis of alternative conceptions in chemistry, as described in the research literature in science and chemistry education, has led to the development of an explanatory framework that encompasses many of the ideas held by chemistry students about chemical substances and phenomena. Research results provided here indicate that many students' conceptual difficulties result from commonsense reasoning. This commonsense approach is based upon a set of assumptions about the natural world and the application of reasoning heuristics that students instinctively follow and apply without hesitating or considering other alternatives. The identification of this explanatory framework may provide a useful model that teachers can use to better understand and even predict ma...
195 citations
TL;DR: In this paper, the underlying science in making a new thin-film thermochromic coating by chemical vapor deposition is described, and the underlying physical chemistry associated with the semiconductor-to-metal transition is discussed.
Abstract: This article covers the background and related science associated with a thermochromic window. A thermochromic window is a device that changes its reflectance and transmission properties at a specific critical temperature. At this temperature the material undergoes a semiconductor-to-metal transition—at low temperature the window will let in all of the sun's energy while above the critical temperature it will reflect the infrared portion of the sun's energy. Hence a thermochromic window could be used to significantly reduce air conditioning costs, which has consequential positive benefit in reducing electricity consumption and hence green house gas emissions. This article details the underlying science in making a new thin-film thermochromic coating by chemical vapor deposition; it describes the underlying physical chemistry associated with the semiconductor-to-metal transition and shows how substitutional doping within a crystal lattice can be used to lower the thermochromic switching temperature.
181 citations
TL;DR: The use of oxidation number instead of valence can result in misleading descriptions of molecules as discussed by the authors, since the relationship between valence and oxidation number breaks down in many cases, and in such situations, the use of the oxidation number can lead to misleading description of molecules.
Abstract: Terms such as valence, oxidation number, coordination number, formal charge, and number of bonds are widely used throughout chemistry. Although each of these terms has a distinct meaning, their utility is lessened by imprecise usage. Valence, for example, is frequently taken to be synonymous with oxidation number. However, while valence and oxidation number are coincidentally equal for many compounds, the relationship breaks down in many cases; in such situations, the use of oxidation number instead of valence can result in misleading descriptions of molecules. The purpose of this article is to clarify these terms and illustrate how the valence of an atom in a molecule provides a much more meaningful criterion for establishing the chemical reasonableness of a molecule than does the oxidation number.
132 citations
TL;DR: The Science Writing Heuristic (SWH) as discussed by the authors is an instructional technique that combines inquiry, collaborative learning, and writing to change the nature of the chemistry laboratory for students and instructors.
Abstract: The Science Writing Heuristic (SWH) is an instructional technique that combines inquiry, collaborative learning, and writing to change the nature of the chemistry laboratory for students and instructors. The SWH provides a format for students to guide their discussions, their thinking, and writing about how science activities relate to their own prior knowledge via beginning questions, claims and evidence, and final reflections. The SWH approach helps students do inquiry science laboratory work by structuring the laboratory notebook in a format that guides students to answer directed questions instead of using a traditional laboratory report. In this approach, students must make a claim (inference) about what was learned through the laboratory experiment and provide evidence to support that claim. Then, through reflective writing, students continue to negotiate meaning from experiment(s) they conducted. This article provides instructors an overview of how to implement the SWH in their chemistry laboratory course.
129 citations
TL;DR: In this article, the Particulate Nature of Matter Assessment (ParNoMA) was used as a pretest and post test to measure students' conceptual understanding of the particulate nature of matter regarding phases of matter and phase changes.
Abstract: Conceptual understanding of the particulate nature of matter (PNM) has been shown to be critical for success in learning chemistry. In this study, a newly developed instrument called the Particulate Nature of Matter Assessment (ParNoMA) was used as a pretest and posttest to measure students' conceptual understanding of the PNM regarding phases of matter and phase changes. The capacity of animations of molecular-level water to remediate PNM misconceptions held by students from middle school through college was investigated and the results of male and female students were compared. The data indicate that molecular-level animations helped students to improve their scores on the ParNoMA. Pretest scores for male students were significantly higher than those for female students; the posttest scores for the students who viewed the animations were equivalent for males and females. Watching the animations seemed to improve the posttest scores of female students, closing the gender gap that existed prior to the int...
120 citations
TL;DR: In this article, a simple laboratory experiment is described to teach students how to measure mass-transfer coefficients by an electrochemical technique, which allows the students to increase their knowledge about mass transfer and its importance in chemical processes.
Abstract: This article describes a simple laboratory experiment to teach students how to measure mass-transfer coefficients by an electrochemical technique. The experiment allows the students to increase their knowledge about mass transfer and its importance in chemical processes. A simple Microsoft Excel spreadsheet allows students to correlate experimental data in laminar and turbulent regimes. Results obtained can be compared with those obtained from a well-known equation given in electrochemistry and chemical engineering books.
116 citations
TL;DR: The authors compared the effectiveness of an electronic student response system (SRS) to deliver ConcepTests with the use of WebCT quizzes for nursing students enrolled in general chemistry, organic chemistry, and biochemistry courses.
Abstract: This paper compares the effectiveness of an electronic student response system (SRS) to deliver ConcepTests with the use of WebCT quizzes for nursing students enrolled in general chemistry, organic chemistry, and biochemistry courses SRS is a Web-based system designed to assist instructors in delivering and analyzing student responses to questions used in lecture and recitation Student responses are captured and summarized graphically, providing students and instructors with immediate feedback WebCT quizzes provide students with another opportunity for practice of the concepts presented in class Student achievement after experience with either or both SRS and WebCT quizzes on teacher-written hour-long exams and an American Chemical Society final exam was investigated Results show that small differences in teacher implementation of both of these innovations can have large effects on student achievement As currently implemented, SRS did not provide opportunities for reflection and review, while WebCT
111 citations
TL;DR: In this article, a method of simulating chemical reaction kinetics by adding rule-based elementary reactions to a classical molecular dynamics simulation is presented. But it is not suitable for the simulation of complex systems.
Abstract: This paper reports a method of simulating chemical reaction kinetics by adding rule-based elementary reactions to a classical molecular dynamics simulation. The method can reproduce many important thermodynamic properties of chemical reactions, and can be used to build interactive software that runs on typical personal computers. Its capacity has many potential applications for learning the core ideas of chemistry.
96 citations
TL;DR: Luminescent molecular thermometers are new-generation analytical tools as mentioned in this paper, which consist of molecular species and inform us of temperature by means of light signals that can be detected with high sensitivity.
Abstract: Luminescent molecular thermometers are new-generation analytical tools. These thermometers consist of molecular species and inform us of temperature by means of light signals that can be detected with high sensitivity. Therefore, luminescent molecular thermometers have a great advantage in measuring the temperature of tiny spaces. In this article, luminescent molecular thermometers are reviewed in terms of their mechanisms and features.
TL;DR: In this paper, the authors describe the results of instituting peer-led team learning workshop sessions as optional accompaniments for the first two years of chemistry (general chemistry and organic chemistry), courses taught in large lecture format.
Abstract: This paper describes the results of instituting peer-led team learning workshop sessions as optional accompaniments for the first two years of chemistry (general chemistry and organic chemistry), courses taught in large-lecture format. About 30% of the students in the courses choose to add this one-credit, two-hour weekly course. Data have been collected for the organic chemistry course over the past five years to compare the outcomes for students who selected workshops with those for students who did not select the workshop option with respect to student success (achievement of a grade of C- or higher), student persistence (completing all three terms successfully in the same academic year), and student performance (percentage of total points accumulated). Students who elected to take the workshops had a somewhat higher overall grade point average (GPA), based on all courses taken (3.26 vs 3.14). However, the gains of the workshop students in each category—success rate (85% vs 69%), three-term persistence...
TL;DR: Tetrahedral chemistry education as discussed by the authors proposes a new conceptual metaphor to enrich our description of chemistry education and support the many existing efforts to help students make connections with the chemistry found in textbooks.
Abstract: The triangle of thinking levels that has become the dominant metaphor for chemistry education has served us well. As that metaphor reminds us, students need to encounter chemistry at the macroscopic, submicroscopic, and symbolic levels to make sense of the molecular world. Yet concerns about public understanding of and trust in chemistry, coupled with the need to continue to attract students into the profession, underscore the importance of framing chemistry education in new ways. This article proposes a new conceptual metaphor to enrich our description of chemistry education and support the many existing efforts to help students make connections with the chemistry found in textbooks. It proposes a metaphorical rehybridization of that triangle of thinking levels into a tetrahedron, where the fourth vertex represents the web of human contexts for chemistry. Tetrahedral chemistry education may reenergize learning inside and beyond the classroom by (i) providing a framework for curriculum reform, (ii) focusi...
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TL;DR: In this paper, students use a commercially prepared cement mix to investigate the factors involved in the hardening of concrete into concrete, and manipulate variables such as concentration, curing temperature, and additions to the mixture, as well as testing the products for strength or hardness.
Abstract: In this Activity, students use a commercially prepared cement mix to investigate the factors involved in the hardening of cement into concrete. Students manipulate variables such as concentration, curing temperature, and additions to the mixture, as well as testing the products for strength or hardness. Saftey concerns are noted for both the preparation and testing. This Activity complements the National Chemistry Week 2006 theme: "Your Home—It's All Built on Chemistry".
TL;DR: In this paper, the authors report the results of a yearlong examination of the effects of an organic laboratory course on students' perceptions about what they were learning and why, and the roles of the instructor and students in the course.
Abstract: Qualitative evaluations of a new curriculum can be very informative, particularly about the effects on student achievement and retention rates There is, however, a great deal of information that this type of program assessment fails to reveal about the reasons a program is successful (or unsuccessful) In this study, we report the results a yearlong examination of the effects of an organic laboratory course on students' perceptions about what they were learning and why, and the roles of the instructor and the students in the course Students enrolled in experimental sections of an open-ended, project-based organic chemistry course were compared with others who were enrolled in a more conventional "cookbook" laboratory course Students were videotaped, interviewed, and asked to complete open-ended questionnaire forms Those who were enrolled in the experimental lab sections were more likely to view the lab as a place to experiment and make mistakes, while those in the conventional sections were more likel
TL;DR: The Peer-Led Teaching and Learning (Workshop) model has been applied since 1998 to a subset of all General Chemistry laboratory sections at the University of Pittsburgh as discussed by the authors, where the workshop model was used to train a group of students.
Abstract: The Peer-Led Teaching and Learning (Workshop) model has been applied since 1998 to a subset of all General Chemistry laboratory sections at the University of Pittsburgh. In the workshop model, the ...
TL;DR: In this paper, student performance in two first-semester general chemistry courses is compared to determine whether a distance learning model can provide a comparable learning opportunity to the conventional lec...
Abstract: Student performance in two first-semester general chemistry courses are compared to determine whether a distance learning model can provide a comparable learning opportunity to the conventional lec...
TL;DR: In this article, the authors examined the usefulness of a conducting polymer, polypyrrole, in the design of molecularly imprinted polymer-based sensors and applied the PAD method for the estimation of success in the preparation of mPpy and for the detection of analyte interaction with complementary cavities imprinted within the polymeric backbone.
Abstract: This article examines the usefulness of a conducting polymer, polypyrrole, in the design of molecularly imprinted polymer-based sensors. Basic electrochemical techniques previously described in this Journal are applied in the preparation of the molecularly imprinted conducting polymer polypyrrole (mPpy). Pulsed amperometric detection (PAD) method is applied for the estimation of success in the preparation of mPpy and for the detection of analyte interaction with the complementary cavities imprinted within the polymeric backbone. Caffeine was selected as a template molecule for molecular imprinting of polypyrrole. Estimation of caffeine concentration has an analytical impact owing to its high biological activity. Moreover, caffeine is well known to the students. Application of electrochemical polymerization techniques enables preparation of molecularly imprinted conducting polymer-based analytical systems. Such systems exhibit an artificially created affinity and can act as synthetic receptors.
TL;DR: In this paper, a simple experiment in which the principle of absorbance may be demonstrated using digital color image analysis was described. Dilute yellow food coloring solutions in water were prepared in known relative concentrations and photographed in transparent cuvettes as a group placed against a diffuse fluorescent white light lightbox.
Abstract: This article describes a simple experiment in which the principle of absorbance may be demonstrated using digital color image analysis. Dilute yellow food coloring solutions in water were prepared in known relative concentrations and photographed in transparent cuvettes as a group placed against a diffuse fluorescent white light lightbox. Image analysis of the intensity of the complementary color (blue) for each solution produced data that conformed to the Beer–Lambert law.
TL;DR: Green chemistry has the potential to recruit innovative and energetic students, repair a damaged public image, and bolster the long-term prosperity of the chemical sector on the domestic and international scale.
Abstract: This Commentary resulted from a series of conversations between an international group of chemistry and chemical engineering graduate students from the 3rd Annual ACS Green Chemistry Summer School, who reflected on their undergraduate education and discussed 1) the areas of green chemistry that were often neglected, 2) the value of integrating green chemistry principles in today's curricula, and 3) strategies educators might use to incorporate green chemistry in their classrooms. We have outlined areas of scientific knowledge that we believe to be of vital importance for the education of future chemists and engineers, as well as graduates of other disciplines including public relations, business, and public policy. Green Chemistry has the potential to recruit innovative and energetic students, repair a damaged public image, and bolster the long-term prosperity of the chemical sector on the domestic and international scale. Instead of eliminating existing courses, we argue that teaching traditional chemist...
TL;DR: Several special scales are used to indicate concentrations of solutions when sugars (sucrose, glucose, fructose, etc.) are the solutes.
Abstract: Several special scales are used to indicate concentrations of solutions when sugars (sucrose, glucose, fructose, etc.) are the solutes. Here, we discuss these scales and their applications to several industries.
TL;DR: The 2005 Nobel Prize in Chemistry was awarded to Yves Chauvin of the Institut Francais du Petrole, Robert H. Grubbs of Caltech, and Richard R. Schrock of MIT as mentioned in this paper.
Abstract: The 2005 Nobel Prize in Chemistry was awarded to Yves Chauvin of the Institut Francais du Petrole, Robert H. Grubbs of CalTech, and Richard R. Schrock of MIT "for development of the metathesis method in organic synthesis". The discoveries of the laureates provided a chemical reaction now used daily in the chemical industry for the efficient and more environmentally friendly production of important pharmaceuticals, fuels, synthetic fibers, and many other products. This article tells the story of how olefin metathesis became a truly useful synthetic transformation and a triumph for mechanistic chemistry, and illustrates the importance of fundamental research.
TL;DR: In this article, an integrated undergraduate laboratory activity involving the synthesis and characterization of a diesel fuel substitute, biodiesel, is presented, where students synthesize biodiesel and measure its heat of combustion, density, and cloud point, then compare these properties to conventional petroleum diesel.
Abstract: An integrated undergraduate laboratory activity involving the synthesis and characterization of a diesel fuel substitute, biodiesel, is presented. Biodiesel is currently a popular topic in the field of green chemistry because it is a non-petroleum fuel that can be efficiently produced from waste vegetable oil. As a fuel, it requires no engine modifications and results in lower pollution emissions including carcinogens and carbon dioxide. Over a three-week period, students synthesize biodiesel, measure its heat of combustion, density, and cloud point, then compare these properties to conventional petroleum diesel. Heats of combustion are measured in a common laboratory bomb calorimeter and cloud point is measured using a UV–vis spectrophotometer.
TL;DR: In this article, a study of a laboratory teaching apprenticeship program designed to improve graduate teaching assistant (GTA) performance is presented. But it is not focused on how to train GTAs as laboratory teachers.
Abstract: We report on a study of a laboratory teaching apprenticeship program designed to improve graduate teaching assistant (GTA) performance. To catalyze GTAs as laboratory teachers we constructed learni...
TL;DR: In this article, a diagnostic multiple-choice test was administered to 157 tenth-grade students (15-16 years old) and the data were analyzed, showing that high school students hold a series of misconceptions both about nuclear chemistry topics related to nuclear stability, half-life, binding energy, practical applications of nuclear chemistry, radioactive decay rate, and basic chemistry concepts that are essential prerequisites for learning nuclear chemistry.
Abstract: This study represents the first attempt to elucidate and detail the types of misconceptions high school students hold relating to basic concepts and topics of nuclear chemistry. A diagnostic multiple-choice test was administered to 157 tenth-grade students (15–16 years old) and the data were analyzed. The results show that high school students hold a series of misconceptions both about nuclear chemistry topics related to nuclear stability, half-life, binding energy, practical applications of nuclear chemistry, radioactive decay rate, and about basic chemistry concepts that are essential prerequisites for learning nuclear chemistry. One of the obstacles to effective learning in nuclear chemistry is that concepts and topics related to it are quite abstract. The fact that students fail to link between macroscopic and microscopic levels of representing matter causes them to use the concepts atom, element, and matter interchangeably. Furthermore, these results identify that the students have neither comprehended the concept of isotope atom nor understood exactly the fact that elements can contain different naturally occurring isotopes. In addition, students demonstrated confusion about the difference between nuclear and chemical reactions. We offer some suggestions for a more effective teaching approach to ensure better learning of nuclear chemistry. One of the implications for teaching is that initially high school chemistry teachers should ensure that students have pre-existing knowledge before starting to teach them the topics related to nuclear chemistry. Teachers also need to emphasize the distinction between chemical and nuclear reactions by using examples. They should provide students with awareness of both the useful applications of nuclear chemistry in daily life and the harmful effects of radioactivity, which are always on the agenda but not given sufficient attention as they are usually placed in the last chapters of chemistry textbooks.
TL;DR: In this paper, the distribution of high school content experiences reported by college chemistry students from 31 four-year colleges and universities in the United States was analyzed using a broad-based survey of 3521 introductory chemistry students and the results indicated that stoichiometry rises above seven other topics studied in high school as most strongly predictive of college chemistry success.
Abstract: Do students who focus on some content areas in high school chemistry have an advantage over others in college chemistry? Published research on high school preparation for college science dates back as far as the 1920s, but results have been mixed. This manuscript seeks to answer this question through the use of a broad-based survey of 3521 introductory college chemistry students. This study provides descriptive analyses showing the distribution of high school content experiences reported by college chemistry students from 31 four-year colleges and universities in the United States. The results indicate that stoichiometry rises above seven other topic areas studied in high school as most strongly predictive of college chemistry success. In addition, three mathematics background predictors, including calculus background, were found to be highly significant.
TL;DR: In response to a reader query, the column traces the origins of the term hypervalent, the various debates surrounding its usage, and the resulting implications for introductory textbooks.
Abstract: In response to a reader query, the column traces the origins of the term hypervalent, the various debates surrounding its usage, and the resulting implications for introductory textbooks.
TL;DR: Microwave irradiation provides a way for flash heating as an alternative to standard thermal heating in chemical reactions and has proven to be of benefit particularly for reactions under dry media (i.e., in the absence of solvents or solid support) as mentioned in this paper.
Abstract: Microwave irradiation provides a way for flash heating as an alternative to standard thermal heating in chemical reactions. This technology has been employed to drastically reduce reaction times and even modify selectivity. In addition to this feature, the use of microwave irradiation may outperform conventional reaction conditions in other aspects, such as easier workup, reduction of the usual thermal degradation products, reduction of toxic and expensive quantities of solvents (green chemistry), and reduction of secondary products. Also, microwave irradiation has proven to be of benefit particularly for reactions under dry media (i.e., in the absence of solvents or solid support) and reactions without catalysts. Our goal is to extend this technology to the academic laboratory and introduce organic chemistry students to microwave-assisted reactions. Thus, we designed an inquiry-based laboratory experience based on the use of a microwave oven as a means for a comparative study of the effect of different c...
TL;DR: In this article, the authors evaluated the extent of agreement with the teachers' definition of chemical literacy by presenting it to members of the Israeli Chemical Society, and a consensus of opinion was reached regarding specific concepts, the context, and learning skills that were suggested by those who defined it.
Abstract: The ongoing reform in science education sets the attainment of "scientific literacy for all" as its main goal, and therefore, teaching high school chemistry should address this aim. Traditionally, scientists from academia were dominant in determining the content and structure of high school chemistry courses. Teachers were then usually involved only in later activities based on syllabi conceived by these scientists. In this study we let chemistry teachers be the main partners in the process of defining chemical literacy. The extent of agreement with the teachers' definition of chemical literacy was evaluated by presenting it to members of the Israeli Chemical Society. A consensus of opinion was reached regarding specific concepts, the context, and learning skills that were suggested by those who defined it. However, the results indicate that scientists perceive "chemical literacy" as reflecting only a few core chemical ideas, whereas teachers perceive it in a broader context that links chemistry with othe...
TL;DR: In this article, open-ended diagnostic questions and semi-structured interviews were used to determine students' misconceptions related to vaporization and vapor pressure, and seven different misconceptions were identified.
Abstract: This study aimed to determine students' misconceptions related to vaporization and vapor pressure. In order to fulfill this aim, open-ended diagnostic questions and semi-structured interviews were used. The diagnostic questions were administered to 70 third-year students enrolled in the Primary Science Teacher Training Department at Ataturk University in Turkey. In addition, 12 students were interviewed in order to clarify their written responses and to further probe students' conceptual understandings of the questions asked in the test. Seven different misconceptions were identified. The results have implications for tertiary-level teaching, suggesting that a substantial review of teaching strategies is needed.