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Many chemistry laboratory exercises follow a given protocol with known results. Such traditional laboratories rarely give students an accurate representation of how research is conducted, the scientific practices involved in research, and the ownership that accompanies developing and carrying out an independent project. Several laboratory reforms have sought to overcome these limitations, including the creation of course-based undergraduate research experiences (CUREs). The CURE design is meant to emulate authentic research in the teaching laboratory by having students perform novel experiments with unknown results. In this article, we describe our implementation of a CURE for an upper-level physical chemistry laboratory course. Our students carried out novel research using molecular dynamics simulations, isothermal titration calorimetry, and stopped-flow kinetics to study ligand binding to the protein human serum albumin. We studied the effects of the CURE laboratory redesign via a mixed-methods approach. We use the CURE Survey by Lopatto and colleagues to record students' perceived gains in course elements and benefits. We also conducted student interviews to gain an in-depth view of their experience with the CURE laboratory. Our findings suggest that implementing a CURE in an upper-level chemistry laboratory results in similar outcomes to other CURE experiences (which most often occur at the introductory level), can standardize undergraduate research training, and can increase student ownership of laboratory work. We conclude that developing CURE courses for upper-level chemistry courses is an effective way of enhancing undergraduate laboratory training and increasing student experience with research. [ABSTRACT FROM AUTHOR]

A four-week mini-project for teaching is described for an experimental physical chemistry or organic chemistry course. The activities included synthesis of a Pd catalyst, PdCl 2 supported on calcined coconut shell fiber, and its use in the preparation of 4-methylbiphenyl via Suzuki-Miyaura cross-coupling reaction. The technical skills and concepts that are typically presented in practical chemistry courses were covered, including notions of surface chemistry – development of new catalysts, modern organic synthesis, gas chromatography techniques, separation of mixtures, and stoichiometric calculations. [ABSTRACT FROM AUTHOR]

First order processes are of paramount importance for chemical kinetics. In a well-established demonstration experiment, the flow of water out of a vertical glass tube through a capillary simulates a chemical first order process. Here, a digital version of this experiment for lecture hall demonstrations is presented. To this end, water flowing out of the capillary is collected in a beaker which stands on an electronic scale interfaced with a computer. The computer generates a plot of the data in real time which is projected during the lecture. Hereby, with proper explanations, a very intuitive grasp of the essence of first order processes is obtained: The rate (represented by the water flow) is proportional to the concentration of the reactant (height of the water column). With a modified setup, consecutive first order kinetics as well as the concept of a rate-limiting step are illustrated. [ABSTRACT FROM AUTHOR]

A new method for teaching advanced laboratories at the undergraduate level is presented. The intent of this approach is to get students more engaged in the lab experience and apply critical thinking skills to solve problems. The structure of the lab is problem-based and provides students with a research-like experience. Students read the current literature, develop new experiments for the curriculum, and then present the work in both oral and poster format. From the instructor's observations, it was found that students take ownership of their experiments and typically apply themselves more than in a traditional lab setting. Student feedback about this approach has been overwhelmingly positive. [ABSTRACT FROM AUTHOR]

This paper considers educators' debates over the proper place of the atomic theory in American and Ontario high schools during the first decade of the twentieth century, in the context of emerging, historic research on the nature of matter. In 1905, University of Toronto chemist William Lash Miller distributed a booklet instructing Ontario teachers how to teach chemistry without the atomic theory. According to Lash Miller and his Toronto colleagues, who edited a new textbook in 1906, teaching the atomic theory to beginners bred flawed and fuzzy reasoning. Lash Miller was a student of Wilhelm Ostwald, who famously doubted the reality of atoms until convinced by Jean Perrin's 1908 experiments on Brownian motion. This paper shows that limiting the role of the atomic theory was part of an effort, both in Ontario and in the United States, to reorient the high school curriculum toward the expanding discipline of physical chemistry, specifically, a vision of physical chemistry indebted to Ostwald. Like the Toronto chemists, Chicago physical chemist Alexander Smith lamented high school textbooks' overreliance on the atomic theory and promoted the use of laboratory terms. Both Lash Miller and Smith met with resistance from high school teachers, who defended the teaching of the atomic theory and advocated a competing view of beginners' pedagogy. These debates were not settled primarily by appeals to evidence, but instead revolved around differing views of the needs and abilities of high school students. [ABSTRACT FROM AUTHOR]

Artificial photosynthesis (AP) is a synthetic chemical process that replicates natural photosynthesis to mass produce hydrogen as a clean fuel from sunlight-driven water splitting (2H2O → O2 + H2). In both natural and artificial photosynthesis, an oxygen-evolving catalyst (OEC) is needed to catalyze oxygen production from water (2H2O → O2 + 4H+ + 4e-). Herein, we present a simple undergraduate laboratory experiment for monitoring the catalytic oxygen-evolution reaction using a dissolved oxygen optical probe, a luminescent probe that can continuously measure the concentration of dissolved oxygen in aqueous solutions. The laboratory experiment consists of two parts. First, students identify and evaluate the necessary criteria for an active molecular O2-evolving catalyst. Second, students use a kinetic protocol based on the method of initial rates to derive an empirical rate law expression and calculate the turnover frequency and rate constant for a benchmark OEC, [RuII(tpy)(bpy)(H2O)]2+ (tpy is 2,2':6',2"-terpyridine; bpy is 2,2'-bipyridine). The use of simple transition metal complexes allows students to easily grasp how the choice of transition metals and the coordinated organic ligands can greatly impact the overall catalytic performance. Students collect time-dependent dissolved oxygen plots, and analyze and interpret oxygen-evolution data using modern equipment. This laboratory protocol is simple, and allows students to relate many fundamental topics such as thermodynamics, kinetics, redox and coordination chemistry, and catalysis to advances in current chemical research to help broaden their understanding of artificial photosynthesis. [ABSTRACT FROM AUTHOR]

The present work extends the topic addressed in the previously published communication "Teaching Atomic Structure: Madelung's and Hund's Rules in One Chart" in this Journal. The update is designed to emphasize the correlation between the periodic table and the atomic structure of chemical elements by demonstrating the architecture of the periodic table based on the atomic structure step-by-step. [ABSTRACT FROM AUTHOR]

Recent science reform documents have called for incorporating authentic scientific discourse into science classes as engaging in discourse has shown to result in numerous benefits. Whether these benefits are observed in students depends upon the quality of the discourse in which they engage. However, characterizing the quality of student-student discourse can be an ambiguous task. In this work, we introduce decentering as one feature of effective student-student interactions that can be used to evaluate the quality of discourse. Decentering refers to the process of differentiating between one's own perspective and another's. Arguments from two process-oriented guided inquiry learning physical chemistry classes are presented to illustrate this concept. Decentering manifests itself in these arguments through careful consideration of alternative arguments. Practitioners and researchers can use the results of this study to facilitate and analyze student-student discourse. [ABSTRACT FROM AUTHOR]

A biography of Michael Polanyi, former scientist, is presented.He was born in Budapest, Hungary in 1891 and studied the subject of physical chemistry from the Technische Hochschule of Karlsruhe, Germany. He then received doctor of philosophy (Ph.D) degree from the University of Budapest in 1917. His scientific works on various topics including X-ray diffraction, chemical kinetics, and reaction of sodium and chloride are explored. Theories based on Polany's various experiments are also discussed.

In this article, a bomb calorimeter experiment and subsequent calculations aimed at determining the strain energy of the cyclobutane backbone are described. Students use several butanol isomers instead of the parent hydrocarbons, and they manipulate liquids instead of gases, which makes the experiment much easier to perform. Experiments show that the estimated strain energy is reasonably close to literature values for cyclobutane. [ABSTRACT FROM AUTHOR]

A competitive educational guessing game "Orbital Battleship" which reinforces Madelung's and Hund's rules, values of quantum numbers, and understanding of periodicity was designed. The game develops strategic thinking, is not time-consuming, requires minimal preparation and supervision, and is an efficient and fun alternative to more traditional forms of education. [ABSTRACT FROM AUTHOR]

Robust and fast methods for chemical or multiphase equilibrium calculation are routinely needed by chemical-process engineers working on sizing or simulation aspects. Yet, while industrial applications essentially require calculation tools capable of discriminating between stable and nonstable states and converging to nontrivial solutions, students are often introduced to the simplest and less efficient equilibriumcalculation methods. In this article, the Gibbs energy minimization technique is presented as a robust alternative way to perform phase-equilibrium calculations and is applied to the determination of 2-fluid phase equilibria in low-pressure binary systems. It is carefully explained how the combination of this technique with an efficient quasi-global minimization method makes it possible to derive a robust PT-flash algorithm. In the frame of project-based learning devoted to develop a tool for building complex phase diagrams, this approach was successfully tested with a group of 100 students. [ABSTRACT FROM AUTHOR]

Introductory chemistry students often have difficulty visualizing the 3-dimensional shapes of the hydrogenic electron orbitals without the aid of physical 3D models. Unfortunately, commercially available models can be quite expensive. 3D printing offers a solution for producing models of hydrogenic orbitals. 3D printing technology is widely available, and the cost of 3D printing "inks" is relatively low. Creation of models requires graphing electron orbital probability distributions in spherical coordinates and exporting as stereolithography (.stl) files (a common format for 3D printing). There is both freeware (CalcPlot3D), and license-requiring (Matlab, Mathematica, Maple) software capable of plotting orbital equations and exporting in the required format. The process of creating the orbitals is relatively simple, and the 3D printing methodology is cost-effective. [ABSTRACT FROM AUTHOR]

A summary of fundamental changes made to the undergraduate physical chemistry curriculum in the Chemistry Department at Gustavus Adolphus College (beginning in the 2013-2014 academic year) is presented. The yearlong sequence now consists of an introductory semester covering both quantum mechanics and thermodynamics/ kinetics, followed by a second semester that covers more advanced and integrated topics. While the initial rationale for changing the physical chemistry sequence was to improve the department's overall curriculum, the process has raised some important questions about the propriety of the traditional approach to physical chemistry education in the 21st century. [ABSTRACT FROM AUTHOR]

In this work we are going to present how an interactive platform can be used as a powerful tool to allow students to better explore a foundational problem in quantum chemistry: the application of the variational method to the dihydrogen molecule using simple Gaussian trial functions. The theoretical approach for the hydrogen atom is quite straightforward, however, the level of complexity increases considerably for the dihydrogen molecule. Although, as shown in this work, it is possible to obtain an analytical expression for the dihydrogen molecule variational integral by "pen-and-paper", this expression cannot be completely appreciated without the proper tools. In this work the "dry" analytical equations were implemented into an interactive platform that allows the students to visualize results (like probability densities and meaningful graphs), play with parameters, and thus gain a deeper understanding of the problem itself. Having an interactive environment is also important as a way of minimizing complex equations, testing analytical results with numerical calculations, among other things, that otherwise would be unachievable by "pen and paper" only. Additionally, in this work the bonding and antibonding behaviors of the dihydrogen molecule were investigated and evaluated in detail. As a final outcome, this article shows that important properties regarding the dihydrogen molecule (like equilibrium bond length and favorability of formation) can be explained and approximated with the variational method. [ABSTRACT FROM AUTHOR]

Encouraging students to participate in collaborative discourse allows students to constructively engage one another, share ideas, develop joint understanding of the course content, and practice making scientific arguments. Argumentation is an important skill for students to learn, but students need to be given the opportunity in class to engage in argumentation. To investigate the importance of instructor facilitation on argumentation, two iterations of one instructor's Process Oriented Guided Inquiry Learning (POGIL) physical chemistry course were studied using the Toulmin analysis and the inquiry-oriented discursive moves frameworks. Data were collected by recording class conversations and interactions taking place in the POGIL classrooms. Initial analysis of an individual instructor's implementation of the POGIL materials provided data regarding the nature of small group and whole class interactions and the nature and quality of student-generated arguments. The instructor was then able to make modifications to the facilitation of that course for the next iteration of the course. Data were collected for this subsequent implementation, and the two sets of implementations were compared. It was found that slight changes in facilitation can lead to significant differences in the types of student interactions and the nature of students' arguments. Simultaneous reporting was useful in encouraging iterative argumentation and discussion among students, and setting expectations that students must be ready to explain how they solved the problem and justify their work helped students develop their argumentation skills. [ABSTRACT FROM AUTHOR]

The article presents the author's views on the history of physical chemistry education at the University of Warsaw after 1939 with reference to the book "Monumenta Universitatis Varsoviensis 1816-2016." Various topics discussed include activities of the university's Department of Physical Chemistry, its transformation in 1969, its important faculties and post-war period in science. Author further discusses diversity in science researches, changed leadership, and 200th anniversary of the university.

The work shortly describes scientific, teaching, and organisational activity of the Chair of Chemistry and then of the Division of Physical Chemistry during after-war period. Presentation is made in five short chapters, covering periods defined by substantial and characteristic processes in our country, resulting in changes in the organisation and work of the Faculty of Chemistry at the University of Warsaw. The first two chapters concern the Chair of Physical Chemistry at the Faculty of Mathematical and Natural Science in the years 1947-1955. The Department of Chemistry was founded in the 1955. The next three chapters describe the activity of the Division of Physical Chemistry in the years 1968-1989, 1990-2005, and 2005-2016 respectively. The work also contains a register, probably incomplete, of employees with university degree, who were employed at the Chair and then at the Division of Physical Chemistry during 61-year period of the activity of the Faculty, i.e. in the years 1955-2016. [ABSTRACT FROM AUTHOR]

The use of electronic formats for obtaining, recording, analyzing, and disseminating data is becoming ubiquitous in classrooms, teaching laboratories, research laboratories, and industry. The undergraduate physical chemistry teaching laboratory provides an excellent opportunity to ensure that upper-division chemistry students gain experience in using electronic means of recording and presenting the results of their experiments. To facilitate this action, computers are used in as many aspects of the course as possible: obtaining introductory material, preparing pre-lab reports, recording data in a simulated electronic lab notebook, and submitting final lab reports. Since the physical chemistry laboratory is an advanced undergraduate course, the students are also given increased responsibility for the experiment, creating their own procedure from papers, textbooks, and other additional information. [ABSTRACT FROM AUTHOR]

A 14-item, multiple-choice diagnostic assessment tool, the quantum chemistry concept inventory or QCCI, is presented. Items were developed based on published student misconceptions and content coverage and then piloted and used in advanced physical chemistry undergraduate courses. In addition to the instrument itself, data from both a pretest, prior to a semester of instruction, and a post-test, after a semester of instruction, are provided. These data suggest that the QCCI is capable of measuring the variation of student conceptual understanding of quantum mechanics in the context of a physical chemistry course and that the instrument is sensitive to gains in student understanding that result from direct instruction in the topic, even when that instruction has a significant mathematical component as is common for this course. [ABSTRACT FROM AUTHOR]

Physical chemistry I at Texas A&M University is an upper division course requiring mathematical and analytical skills. As such, this course poses a major problem for many Chemistry, Engineering, Biochemistry and Genetics majors. Comparisons between participants and non-participants in Supplemental Instruction for physical chemistry were made using analyses that controlled for prior mathematical ability and academic achievement. When controlling for prior mathematical ability, no statistical evidence was found that supplemental instruction attendance increased the final grade in physical chemistry I. However, when controlling for prior academic achievement, students with lower prior achievement were found to benefit from supplemental instruction while high achieving students derived no benefit. [ABSTRACT FROM AUTHOR]

Students of physical chemistry in biochemical disciplines need biochemical examples to capture the need, not always understood, of a difficult area in their studies. The use of thermodynamic data in the chemical reference state may lead to incorrect interpretations in the analysis of biochemical examples when the analysis does not include relevant conditions to the biochemical state. The definition of a new reference state for biochemical reactions in 1994 still contends with the low number of published and consistent compilations of thermodynamic data. To fill the gap in the organized presentation of biochemical thermodynamic data, reliable sources of databases of biochemical thermodynamic data are discussed, along with textbooks and specialized academic sources. [ABSTRACT FROM AUTHOR]

While the research field of quantum dynamics (QD) benefits from advances in modern computational power, the educational field of QD paradoxically does not. We have developed an open-access, interactive, electronic notebook that leverages a user-friendly interface to engage a new generation of visual learners with QD. We begin each topic (e.g., adiabaticity, light-matter interactions, and relaxation processes) with essential questions, issues, and background that orient the learner; we then move directly to visual explorations of the phenomena, where the learner can immediately manipulate parameters that control and drive the physics. This notebook requires only a computer that can run Wolfram's computable document format (CDF) files (both the notebook and CDF player are free) and enables learning in a variety of contexts and grade levels: flipped classrooms, small groups, and high school students through advanced researchers. Without sacrificing rigor, Quantum Dynamics...with the Dynamics! (QDWD) aims to develop physical intuition and is built in the spirit of hands-on experimentation with immediate and visual results. The hierarchical structure of QDWD lends itself to differentiated instruction, where a motivated or advanced student can explore the computer code, mathematical formalism, and underpinning physics. [ABSTRACT FROM AUTHOR]

An analysis is presented of the experience and lessons learned of running a MOOC in introductory physical chemistry. The course was unique in allowing students to conduct experimental measurements using a virtual laboratory constructed using video and simulations. A breakdown of the student background and motivation for taking the course is presented, and the student feedback on the course is also provided. It is concluded that even practical based chemistry courses can be successfully delivered online and such courses have the potential to provide a valuable addition to campus based chemistry teaching at university level. [ABSTRACT FROM AUTHOR]

A nationwide survey of the undergraduate physical chemistry course was conducted to investigate the depth and breadth of content that is covered, how content is delivered, how student understanding is assessed, and the experiences and beliefs of instructors. The survey was administered to instructors of physical chemistry (N = 331) at American Chemical Society certified colleges and universities in the United States. The majority of instructors (N = 187) provided contact information, allowing responses to be associated with their institution. The goal of this preliminary study is to provide an awareness of the current state of physical chemistry courses across the United States. Several relationships regarding the course curriculum were investigated such as depth versus breadth of course content, and goal for understanding versus types of assessment questions. Also, several relationships regarding instructor beliefs and experiences were investigated such as degree of teacher preparation experience versus course delivery, and instructor beliefs about the challenging nature of physical chemistry education versus proposed strategies to overcome those challenges. Information gained from this study may inform the development of new teaching practices, curriculum, assessments, and resources for physical chemistry education, as well as encourage instructors of physical chemistry and researches of chemical education to work together to improve student understanding of physical chemistry. [ABSTRACT FROM AUTHOR]

This paper describes a student designed experiment using titrations involving conductivity measurements to identify unknown acids as being either HC1 or H2S04, and to determine the concentrations of the acids, thereby improving the utility of standard acid-base titrations. Using an inquiry context, students gain experience with titrations, conductivity, procedural design, and analysis of results. The results of the experiment indicate that it is robust enough for use with advanced high school or college general chemistry students. [ABSTRACT FROM AUTHOR]

The procedure of a physical chemistry experiment for university students must be designed in a way that the accuracy and precision of the measurements is properly maintained. However, in many cases, that requires costly and sophisticated equipment not readily available in developing countries. A simple, low-cost experiment to determine isobaric expansion coefficient has been designed and successfully implemented. The practice includes measurement of density at controlled temperatures and mathematical and graphical treatment of data. In spite of the simplicity of the experiment, the precision and accuracy of the measurements are not forfeited. [ABSTRACT FROM AUTHOR]

The transport of molecules across biological membranes are critical for most cellular processes. Membrane permeability is also a key determinant for drug absorption, distribution, and elimination. Diffusion, that is, the migration of matter down a concentration gradient, is a simple mechanism by which both endogenous and drug molecules can enter (or exit) cells. This paper describes a simple and engaging physical chemistry undergraduate laboratory experiment for health and life sciences students studying diffusion of drug and dye molecules in solution. In this experiment, the diffusion of amitriptyline hydrochloride, ranitidine hydrochloride, and tartrazine across a cellulose dialysis membrane is evaluated using an innovative macro and microscale approach. Compound concentration in solution as a function of time is obtained both from conductivity measurements of 25 mL solutions and from absorbance measurements of 100 µL samples taken in a 96-well microplate. By using solutions of different concentrations, the permeability coefficient of the membrane and the diffusion coefficient of the tested compounds are determined. Comparison of both methods, which yield similar values, is performed, which shows that either one of the approaches is suitable to independently conduct the experiment. On the basis of diffusion phenomena, the important pharmaceutical issue of absorption and transport of drugs through passive diffusion across biological or artificial membranes is presented. [ABSTRACT FROM AUTHOR]

The method of least-squares (LS) has a built-in procedure for estimating the standard errors (SEs) of the adjustable parameters in the fit model: They are the square roots of the diagonal elements of the covariance matrix. This means that one can use least-squares to obtain numerical values of propagated errors by defining the target quantities as adjustable parameters in an appropriate LS fit model. Often this will be an exact, weighted, nonlinear fit, requiring special precautions to circumvent program idiosyncrasies and extract the desired a priori SEs. These procedures are reviewed for several commercial programs and illustrated specifically for the KaleidaGraph program. Examples include the estimation of ΔHº, ΔSº, ΔGº, and Kº(T) and their SEs from Kº (equilibrium constant) values at two temperatures, with and without uncertainty in T, which is included using the effective variance method, a general-purpose LS procedure for including uncertainty in independent variables. In some cases, the target quantities can be obtained from the original data analysis, by redefining the fit model to include the quantity of interest as an adjustable parameter, automatically handling correlation problems. Examples include the uncertainty in the fit function itself, line areas from spectral line profile data, and the analysis of spectrophotometric data for complex formation. [ABSTRACT FROM AUTHOR]

This undergraduate physical chemistry laboratory exercise introduces students to the study of probability distributions both experimentally and using computer simulations. Students perform the classic coin toss experiment individually and then pool all of their data together to study the effect of experimental sample size on the binomial distribution. Simulations of the coin toss experiment are also performed using the software package LabVIEW. LabVIEW facilitates the creation of complex computer programs in a short period of time, even by beginner programmers. Histograms in LabVIEW are displayed in real time with students adjusting the number of simulated coin tosses on the fly using a virtual knob or a slider, up to 1 million individual trials. This allows the students to see firsthand the evolution of the binomial distribution into the Gaussian distribution with a large sample size. [ABSTRACT FROM AUTHOR]

The use of the Scanning Tunneling Microscope (STM) in university teaching allows for both a very easy access to the atomic and electronic structure of solids and to gain insight into various, sometimes hardly comprehensible, physico-chemical phenomena like the quantum mechanical tunneling effect. The new generation of easy-to-use STMs, specially designed for teaching purposes, allows self-operation and data-analysis by interested university students. The present manuscript critically discusses the possibilities of STM in university teaching, but also gives an outlook to the use in high-school teaching. [ABSTRACT FROM AUTHOR]

In the article "Why Are Some Reactions Slower at Higher Temperatures?" published in this Journal, Revell and Williamson explained, from the enthalpic and entropic aspects, why an A + B → P reaction may proceed more slowly at higher temperatures via an A + B C → P mechanism using the pre-equilibrium approximation. Their explanation is convincing but may be too abstract for undergraduate physical chemistry students to understand fully. In this communication, a numerical implementation and graphical demonstrations of their explanation are provided for students to use to "see" for themselves a negative activation energy. Although Revell and Williamson perfectly explained the negative temperature dependence of the A ↔ B C → P reaction rate, great caution must be exercised when their explanation is applied to interstellar chemistry where the pre-equilibrium approximation may be invalid and statistical thermodynamics functions may be ill-defined. [ABSTRACT FROM AUTHOR]

In undergraduate physical chemistry, Schrodinger's equation is solved for a variety of cases. In doing so, the energies and wave functions of the system can be interpreted to provide connections with the physical system being studied. Solving this equation by hand for a one-dimensional system is a manageable task, but it becomes time-consuming once students aim to make various changes and investigate the impact of those changes on the results. To address this challenge, numerical methods, such as the shooting and linear finite-difference methods, have been utilized to quickly solve Schrodinger's equation. In this technology report, we use the Python programming environment and the three-point finite-difference numerical method to find the solutions and plot the results (wave functions or probability densities) for a particle in an infinite, finite, double finite, harmonic, Morse, or Kronig-Penney finite potential energy well. We believe that this technology report will educate undergraduates on the basic tools of computer programming, data analysis, and making connections between mathematical models and the physical systems with which they are associated. [ABSTRACT FROM AUTHOR]

This paper reports a study on retention of differential and integral calculus concepts of a second-year student of physical chemistry at a Danish university. The focus was on what knowledge the student retained 14 months after the course and on what effect beliefs about mathematics had on the retention. We argue that if a student can quickly reconstruct the knowledge, given a few hints, this is just as good as retention. The study was conducted using a mixed method approach investigating students’ knowledge in three worlds of mathematics. The results showed that the student had a very low retention of concepts, even after hints. However, after completing the calculus course, the student had successfully used calculus in a physical chemistry study programme. Hence, using calculus in new contexts does not in itself strengthen the original calculus learnt; they appeared as disjoint bodies of knowledge. [ABSTRACT FROM PUBLISHER]

Two suggestions for instruction in chemical equilibrium are presented, along with the evidence that supports these suggestions. The first is to use diagrams to connect chemical reactions to the effects of reactions on concentrations. The second is the use of the majority and minority species (M&M) strategy to analyze chemical equilibrium systems. Two studies are presented in support of these suggestions. [ABSTRACT FROM AUTHOR]

An experiment focusing on the creation of phase diagrams involving nonconvalent derivatives of hydroquinone and bis[N,N-diethyl]terephthalamide (HQ-DETPA) is presented. A phase diagram was assembled by taking samples of different compositions (i.e., 40% hydroquinone and 60% bis[N,N-diethyl]terephthalamide, 70%/30%, etc.) and determining the melting points of each sample. This experiment is suitable for students enrolled in a physical chemistry class or materials science course and was effectively accomplished by three pairs of students. The experiment requires two 3-h lab sessions. Background information, experimental procedure and hazards, and results of the research are detailed. Results indicate that the noncovalent derivatization successfully provides a co-crystal that assembles into a 50:50 molar ratio. The eutectic points are shown to take place at the 25:75 and 75:25 molar ratios, respectively. Because entropy was the driving force behind the assembly of the co-crystals, the presence of a maximum point on the phase diagram, which represents the highest value of enthalpy and lowest point of entropy, was also witnessed and occurred at the 50:50 molar ratio of HQ to DETPA. [ABSTRACT FROM AUTHOR]

The article focuses on the history, present, and future perspectives of analytical chemistry teaching in China. Topics discussed include the release of the earliest chemistry book titled "Quantitative Chemical Analysis," Yuanyu Cao in 1939, the offering of five chemistry courses including organic, physical, and analytical chemistry, and the consideration of the advanced analytical chemistry as an applied science.

The determination of the solid--liquid phase diagram of a binary system is always used as an experiment in the undergraduate physical chemistry laboratory courses. However, most phase diagrams investigated in the lab are simple eutectic ones, despite the fact that complex binary solid-liquid phase diagrams are more common. In this article, the cooling curves of phenol--t-butanol mixtures are measured and the phase diagram of this system is found to give three eutectic points and two congruent melting points. The laboratory provides the students a practical way to investigate a complex system with their own efforts and teamwork spirit. [ABSTRACT FROM AUTHOR]

We have designed an exercise suitable for a lab or project in an undergraduate physical chemistry course that creates a Microsoft Excel spreadsheet to calculate the energy of the S0 ground electronic state and the S1 and T1 excited states of H2. The spreadsheet calculations circumvent the construction and diagonalization of the Fock matrix and thus can be accomplished by any undergraduate chemistry student with basic calculus skills. The wave functions of the S0, S1, and T1 states of H2 are constructed from the symmetry-adapted bonding and antibonding molecular orbitals (MO). All quantum mechanical integrals are estimated using the Monte Carlo integration method. Due to the stochastic nature of the spreadsheet calculations, 25 runs were carried out to obtain the mean energy of the S0, S1, and T1 electronic states of H2. The accuracy of the spreadsheet calculations is comparable to that of the HF/STO-3G calculations. The atomic and molecular orbitals and the energy components can be easily calculated and plotted for better visuahzation and understanding of essential quantum chemical concepts. This spreadsheet can also be adapted to tackle a wider range of quantum chemistry problems with different levels of complexity. [ABSTRACT FROM AUTHOR]

This teaching activity consists of challenging students to explain the working principle behind three scientific toys: a drinking bird, a radiometer, and a Stirling engine. The transformation of heat (q, thermal energy generated by a temperature difference) into work (w, mechanical energy manifested as motion) is implicit in the working of these toys. Such a transformation constitutes a central argument in the conceptual and historical development of entropy (S) and of the second law of thermodynamics (SLT). The observation and the understanding of the common working principles of these toys promoted a positive reaction by students toward the formal development of a conceptual understanding of the SLT and the concept of entropy. [ABSTRACT FROM AUTHOR]

An experiment is described where students determine the binary phase diagram of mixed monolayer films of pentadecanoic acid (C15H30O2) and isopalmitic acid (C16H32O2). They do this by using Langmuir--Blodgett troughs to measure isotherms, surface pressure (π measurements as a function of surface area, of the mixed films above an aqueous surface. The experiment is appropriate for third-year physical chemistry students. Students determine the surface pressure of the start of the phase transition between the liquid expanded (LE) phase and the tilted condensed (TC) phase from their isotherms and use it to obtain a boundary line between the LE and coexistence region. They also calculate the mole fraction of the solution in the tilted condensed phase at the pressure where the beginning of the LE to TC transition occurs to obtain the boundary line between the coexistence region and the TC region, allowing the students to create a binary phase diagram for the LE to TC transition. Students also integrate their isotherms to determine the free energy of mixing of theft solutions at two surface pressures. This experiment allows for several variations with different types of phase diagrams, and students seemed to enjoy the more modern take on the classic binary phase diagram experiment. [ABSTRACT FROM AUTHOR]

All pH calculations for simple acid--base systems used in introductory courses on general or analytical chemistry can be carried out by using a general procedure requiring the use of predominance diagrams. In particular, the pH is calculated as the sum of an independent term equaling the average pKa values of the acids involved in the diagram step and a concentration-dependent value, calculated as the ratio between ΔpC (that is, --log Cacid + log Cbase, corresponding to the predominant species involved in the predominance diagram step) and the number of pH-controlling acid--base pairs involved in the diagram step (one or two for conjugate or nonconjugate systems, respectively). A number of acid--base features can be readily explained via this procedure. This methodology can be extended to complexation equilibria. [ABSTRACT FROM AUTHOR]

The design and construction of an apparatus to measure the optical birefringence of a liquid crystal is described. The instrument also includes temperature control and monitoring circuitry to allow for the measurement of the nematic-to-isotropic phase transition temperature. An important feature of this design is that the students are able to build the optical bench section of the instrument from a kit of parts supplied. The electronics instrumentation for the illuminator, photometer, and temperature controller functions are all low-cost designs using common components, yet provide more than adequate accuracy for the measurements required. The entire instrument cost is $430, an estimated cost reduction of approximately $3000 compared to the design previously proposed by Waclawik et al. This instrumentation is suitable for second or third-year undergraduate students in materials science or physical chemistry courses. [ABSTRACT FROM AUTHOR]

A solid-state crystal structure laboratory exercise for undergraduates in either a general chemistry course or a more advanced inorganic chemistry course is described. Students explore the lattice arrangement of atoms in unit cells by building models supplied by the Institute for Chemical Education. Emphasis is placed on building three-dimensional visual models of various crystal systems to display close packing of atoms, to identify tetrahedral and octahedral holes, to reveal number of atoms per unit cell, and to highlight ion coordination numbers and size differences. The relationship between solid-state bonding and a material's physical properties is emphasized for elemental carbon. [ABSTRACT FROM AUTHOR]

We demonstrate that the formula for irreversible expansion work in most chemical thermodynamics textbooks does not apply during the expansion process. Instead of the "external pressure" Pext, the pressure Psys,mb on the piston or other moving boundary (hence the subscript mb), which is nearly equal to the system pressure Psys, should be used in the integral over volume. This formula only requires that Psys(V) and T are well defined, that is, a system of uniform P and T ("uPT") undergoing a "uPT process", which may be irreversible. An instructive example is an expanding gas accelerating a bullet horizontally and performing work without a conventional external pressure. We emphasize that δw = -Psys,mb dV ≈ -Psys dV is the only useful formula for infinitesimal PV work during a uPT process. The quasistatic approximation Psys,mb = Psys and δw = -Psys dV is usually excellent and enables analyses of irreversible uPT processes, for example, in heat engines; friction in the surroundings and a large piston mass improve the approximation. Slow chemical reactions at constant T and P are quasistatic, and many equations in advanced chemical thermodynamics apply specifically to uPT or quasistatic processes. We show that the equality dS = δqirr/T applies in irreversible quasistatic processes without composition change. In short, with well-defined P and T at constant composition, the simple equations for reversible processes are usually excellent approximations even when the process is irreversible. [ABSTRACT FROM AUTHOR]

The temperature dependence of the Gibbs energy and important quantities such as Henry's law constants, activity coefficients, and chemical equilibrium constants is usually calculated by using the Gibbs-Helmholtz equation. Although, this is a well-known approach and traditionally covered as part of any physical chemistry course, the required mathematical treatment for solving the equation can be tedious and prone to mistakes especially when polynomial expressions for the heat capacities are used. In this article, an alternative approach is introduced in which a simple algebraic equation can provide quick and accurate results for the temperature dependence of the Gibbs energy and chemical equilibrium constants. The comparison against the conventional methods and values reported in the literature validate the effectiveness of the proposed equation. [ABSTRACT FROM AUTHOR]

A series of experiments employing scanning tunneling microscopy (STM) have been developed for the physical chemistry laboratory. These experiments are designed to engage students in cutting edge research techniques while introducing and reinforcing topics in physical chemistry, quantum mechanics, solid-state chemistry, and the electronic structure of molecules and materials. In the first of three experiments, students are introduced to the basics of STM operation while imaging and conducting spectroscopy on the highly oriented pyrolytic graphite (HOPG) surface. Images of the surface are used to determine the crystal structure of the material, and scanning tunneling spectroscopy is used to determine the electronic properties of the material and study the tunneling phenomenon. In the second experiment, the students image the Au(111) surface as well as a series of alkanethiol self-assembled monolayers (SAMs) of different chains lengths on the Au(111) surface. They examine the structural and electronic properties of the metal surface and the adlattice structure of the film. Finally, in the third experiment, the students examine the conductance of molecules adsorbed onto the Au(111) surface, including the alkanethiol SAMs and a thiol-tethered porphyrin molecule or a dimercaptostilbene embedded into the SAM matrix. By measuring the tunneling efficiency and spectroscopic characteristics of these molecules, the students can explore the relationship between chemical structure and charge transport efficiency. The experiments provide advanced chemistry students an opportunity to view and study materials at the atomic and molecular length scales and provide an opportunity to apply their understanding of quantum mechanical concepts to real systems. [ABSTRACT FROM AUTHOR]

Assessment instruments developed specifically for chemistry classrooms have increased in number over the past decade. In the design, development, and evaluation of these instruments, the chemical education community has adopted many of the practices and standards used by the greater assessment communities. Methodologies for creating new assessment instruments now include collecting broad evidence for the validity of the uses and interpretations of data derived from an assessment instrument. The focus of this study is the design, development, and qualitative evaluation of concept inventory items for the Thermochemistry Concept Inventory (TCI). Qualitative research studies were used to obtain feedback from the primary stakeholders of the TCI. Evidence for content and response process validity are provided and used as arguments against the two threats to validity: construct underrepresentation and construct-irrelevant variance. In addition, a determination of the most important thermochemical topics taught in general chemistry classrooms is derived using feedback from general chemistry instructors' responses to an online survey. Semistructured, think-aloud interviews were used to identify alternative conceptions used by students answering open-ended questions. Qualitative data were used to develop a series of multiple-choice items that were then evaluated by students in retrospective think-loud interviews. These student interviews, along with additional interviews with general chemistry instructors, provide evidence for the response process validity of the items. [ABSTRACT FROM AUTHOR]

The equilibrium between phases is a key concept from the introductory physical chemistry curriculum. Phase diagrams display which phase is the most stable at a given temperature and pressure. If more than one phase has the lowest Gibbs energy, then those phases are in equilibrium under those conditions. An activity designed to demonstrate the phase rule and to encourage deeper understanding of the Clapeyron equation is presented. This activity uses a mechanical drawing toy (such as an Etch A Sketch) with horizontal and vertical dials that can be adapted to explore mathematical relationships in a graphical situation. This activity is designed primarily for students taking second- or third-year physical chemistry, although some aspects of the activity would be appropriate for first-year general chemistry. [ABSTRACT FROM AUTHOR]

A three-part project for students in physical chemistry, computational chemistry, or independent study is described in which they explore applications of valence bond (VB) and molecular orbital-configuration interaction (MO-CI) treatments of H2. Using a scientific spreadsheet, students construct potential-energy (PE) curves for several states of H2 from the kinetic and potential energies, calculated from closed-form analytical expressions of the ten unique integrals arising from the Born-Oppenheimer Hamiltonian. For this project students use hydrogen 1s basis functions that include a screening parameter. From the calculated PE curves, they find the dissociation energy, De, and equilibrium internuclear distance, Re. In part I students use the Heitler-London (VB) form of the wave function to obtain the PE curves. In part II they optimize the value of the screening parameter to improve the results, and in part III they explore the treatment of H2, using both the simple MO wave function and the application of CI, with and without screening parameter optimization, to obtain the PE curves. Students compare their De and Re results with the experimental values. A set of questions, exercises, and a sample spreadsheet are provided as Supporting Information. [ABSTRACT FROM AUTHOR]