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Field-flow fractionation (FFF) is an emerging elution-based analytical technique for separation of liquids. Some general concepts of physical chemistry and separation science through gravitational FFF are discussed.

The study demonstrates that the solvent present in a system can highly alter and control the chemical equilibrium of a system. The results show that the dipole moment and polarizibility of a system can be highly altered by using different mixed solvents.

A report is presented to describe how students can be empowered to construct the full, double minimum inversion potential for ammonia by performing intrinsic reaction coordinate calculations. This work can be associated with the third year physical chemistry lecture laboratory or an upper level course in computational chemistry.

Metal rods of high purity may be used to construct a display of relative densities for teaching purposes. Such teaching leaves a more lasting impression of relative density than looking at tabulated densities or bar graphs and this can be further reinforced by having students prepare plots of experimental densities of metal versus (atomic mass)/[radius.sup.3] for close-packed and body-centered cubic structures.

The importance of considering instructional context when evaluating educational software was underscored for me while reviewing an advance copy of the CD-ROM Physical Chemistry (2002) by Laidler, Meiser, and Sanctuary, [...]

The power of seeing entropy as the spreading/sharing of energy, in classical and molecular thermodynamics in important equilibrium situations and chemical processes is substantiated. The subtlety or difficulty of many aspects of thermodynamics involving entropy is acknowledged. Several aspects of this topic are explored.

Semiconductor nanocrystals can be a visual aid in introducing the particle in a box for students of physical chemistry learning about quantum mechanics. An overview of methods for preparing nanocrystals is presented, and the preparation of CdSe nanocrystals by the pyrolysis of organometallic precursors is described in detail.

Predictors of success in physical chemistry have been studied in the first longitudinal study that looks at this area. Hypotheses were based on success in previous chemistry, mathematics, and physics courses. Success in physical chemistry correlated strongly with the final grade in the second course in calculus and with the final grade in the physics sequence.

Students of physical chemistry can learn about nuclear magnetic resonance and related instrumentation and techniques using a classic experiment with some modifications, the modified 2,4-pentanedione keto-enol tautomer experiment. Modifications have been student tested and include sample preparation for Fourier transform (FT) NMR instruments, in-depth analysis of the proton spectrum acquired with a medium field NMR and examination of the temperature dependence of the keto-enol equilibrium. Differences between the keto-enol continuous-wave (CW)-NMR experiment found in manuals and the modified one are discussed as is the remote use of an Internet-capable NMR instrument. Extensions of the experiment to the study of other nuclei and experiments possible because of modern NMR instruments are considered.

A lab in which upper-division undergraduate physical chemistry students determine the index of refraction of a solid material at various wavelengths using a reference liquid whose index of refraction is well known as a function of wavelength and temperature has been developed. Students are exposed to some simple concepts of light scattering at solid-liquid interfaces. A CaF(sub.2)-hexadecane mixture is used with a UV-vis spectrophotometer.

A chemically relevant model has been developed for teaching the second law of thermodynamics. The model illustrtes such concepts as path dependence, reversibility, and extrapolation in trms of electrochemistry and calorimetry. The methods usually used to teach students beyond the first year would be less challenging to students if they had more relevance to chemistry. A chemically relevant thought experiment is suggested

Students can use determination of the rotameric stability of 1,2-dihaloethanes using infrared (IR) spectroscopy, a combined experimental and computational project, to learn about physical chemistry. Quantitative application of IR spectroscopy in characterizing physical properties of molecules intermediate in size is seen. Students can look into the intrinsic electronic-based substituent effects and also into their impact on the relative conformation energetics, force constants and vibrational frequencies. They learn more, too, about the profound effects solvent interaction can have on relative energetics of rotational conformers.

An experiment in materials chemistry involving chemical vapor deposition of carbon nanotubes can be useful in teaching first-year graduate students of chemical and materials physics or advanced undergraduates about an exciting area of nanotechnology, carbon nanotube growth and characterization. Iron-doped alumina catalyst particles are synthesized and various amounts of Fe(NO(sub.3))(sub.3).9H(sub.2)O dissolved in ethanol, then groups of 4-5 students work on the experiment.

The American Chemical Society held a symposia for college chemistry teachers to focus on changes in chemistry education in the 21st century. Seven symposiums were held, each focusing on a particular area of chemical education. A listing of the papers for each symposium is included.

The constituent additivity model of the heat capacity of complex inorganic solids is described with presentation of examples of the use of the model. Its basis and the uncertainty that it brings into the determination of related thermodynamic quantities are discussed. For teach thermodynamics and for comparison with heat capacities of inorganic solids determined in undergraduate laboratory experiments is may be of interest. The Dulong-Petit law and background for the new model are discussed.

Telling stories occasionally in the teaching of thermodynamics and related areas to illustrate aspects of principles or tell about personalities or historical steps and missteps can help to keep students more alert and receptive to ideas. Scientists discussed include Joule, William Thomson (Lord Kelvin), Wolfgang Pauli, John Waterston, Benjamin Franklin, Avogadro, Evert Gorter, Arrhenius, Newton, Boltzmann, Maxwell, Fourier, Bose, J. Willard Gibb and others.

A useful but limited number of compounds that can be combined to give a large number of binary systems suitable for undergraduate physical chemistry lab courses is given. The almost infinite number of combinations of substances is limited in these course, in practice, by several factors, among them the temperature range of melting points, the toxicity, and the price of the chemicals. The compounds used are durene, biphenyl, naphthalene, diphenylmethane, triphenylmethane and phenanthrene.

A general spreadsheet approach can be used to acquaint physical students more directly with the logical principles and computational methods used to find the best-fit parameters. It can be used to help students to understand issues surrounding uncertainty assessment the importance or weight of parameters in a fit and correlations between parameter choices. The approach relates to confidence intervals and envelopes, curve fitting, correlations, and Monte Carlo visualizations for multilinear chemistry problems. Data for three cases are given.

A physical chemistry experiment using dibucaine has been developed for teaching students about simultaneous determination of the ionization constant and the solubility of sparingly soluble drug substances. They use the inverse titration method with dissolution of a precipitate and gain experience with potentiometry and spectrophotometry.

Undergraduate students of physical chemistry can learn about photochromism and photochemical kinetics from an experiment they can do in the laboratory. It might also be used at the nigh school level in special courses. It has simplicity, speed and low cost, yet deals with relatively complex chemical concepts. Students determine parameters for the decoloration process. For excitation a commercial photographic flash unit with the plastic cover removed is used. The experiment could be expanded to include solvent effects more specifically.

Several benefits for students of physical chemistry can come from an exercise using error estimates for fitted parameters as applied to HCl/DCl vibrational-rotational spectroscopy. Several important topics from model building and statistics are brought together with a number of possible extensions. A short review of a model for vibrational and rotational energy levels is presented with explanation of how it can be fit to experimental data. A Monte Carlo sampling technique that gives rigorous error estimates for each of the fitted parameters is described.

An analysis of the adiabatic approximation using the coupled harmonic oscillator system to show some key features is presented. Students in advanced undergraduate or beginning graduate-level physical chemistry and quantum mechanics courses are usually introduced to two approximate treatments. They now should learn about the self-consistent field or Hartree-Fock treatment of electronic problems and the adiabatic or Born-Oppenheimer separation of the treatments of the electronic and nuclear degrees of freedom. It is found that the adiabatic approximation is most accurate when the difference between the ground state energies for the two oscillators is large. Saying that the adiabatic ground-state energy of a system is always less than the ground state energy is justified only if no other approximations are introduced.

Rubber elasticity and its thermodynamics are discussed with material suitable for undergraduates taking thermodynamics courses for various disciplines, among them chemistry, physics, materials science and engineering. A thermodynamic study of a rubber band at constant volume under uniaxial stress has been carried out and is related to its equation of state. This material helps to fill a gap left in most textbooks for thermodynamics. Topics include ideal elastomers, state variables, thermoelastic inversion and temperature changes in adiabatic stretching.

A new and elegant method using very common equipment has been developed to give a much more precise result than comes from the usual laboratory experiments to find absolute zero used in general chemistry or physical chemistry college courses. The method measures a gas volume with standard deviation of less than 10 K. Reported values of the vapor pressure of water at various temperatures to extract the volume of dry air from the volume of a sample of wet air are used. As many as 20 data points can be collected in one trial. Many gas laws are applied and illustrated in the activity. Results are presented.

Active-learning methods for students of physical chemistry are discussed. Cooperative learning has been shown to be very effective. It develops important learning process skills as well as helping students to gain better understanding of the course material. With active-learning methods, it makes for a richer and more satisfying learning environment. Courses at the University of Tennessee, one a biophysical chemistry course, are described, with information about student responses, which were favorable.

An investigation of factors which influence student performance in physical chemistry has been carried out. Perceptions of the difficulty of this field of study and perceptions on the part of professors of what qualities students need to succeed have been considered with a view to finding out whether they have any basis in fact. Students' perceptions about their own ability or experience did not correlate with performance, but math skills, especially with word problems, were a factor. It was found that having logical thinking skills, as seen from performance of the Group Assessment of Logical Thinking, i s helpful to performance. Students and teachers are at odds in physical chemistry courses. Instructors can organize the courses to best reach students if they have knowledge of what works.

Demonstration of an equilibrium shift in a gaseous nitrogen oxides mixture is widely used in the teaching of chemistry, general or physical, but the textbook explanation of color change is often not satisfactory. A good explanation would take into account the noticeable heating upon compression and extremely fast chemical reactions in the system, with relaxation time on the order of a microsecond.

The explanation of multistability, a basic problem for understanding the phenomena, has not been presented for students although nonlinear phenomena such as oscillating chemical reactions and chaos are shown pedagogically in various places. A simplified model is given with possible steady states of the system shown in 3-D space. The concentration of three species that can be monitored experimentally are plotted along three axes. Topics include the Bray-Liebhafsky oscillatory reaction and multistability within that model.

Wave functions for hindered internal rotation and numerical evaluation of energy levels for upper-level physical chemistry students are discussed. A simple, efficient numerical method is introduced. It is the finite-difference boundary-value method and very convenient for one-dimensional periodic problems such as internal rotation ones. The math is mostly straightforward. The quantum mechanics is at an introductory level, so those who do not follow the math would find results interesting.

Light-scattering technology in the undergraduate curriculum is discussed. At the University of Northern Iowa, a Wyatt miniDAWN light-scattering detector was acquired and experiments using the technology to measure the molecular weight of macromolecules replaced an outdated experiment using determination of molecular weight using freezing-point depression. The technique also has great potential in biochemistry teaching and in other areas of undergraduate instruction and is valuable for undergraduate research. Practical and pedagogical problems are discussed.

Undergraduate students of chemistry should learn how to use the available software as computer algebra systems increase and cost goes down. Mathematica is shown to be a powerful tool when used to do the extensive algebra inherent in certain types of derivations and calculations. Illustrating the actual Mathematica instructions that lead to the virial coefficients for the van der Waals equation of state for physical chemistry students was the goal. The instructions can be a model for more sophisticated equations of state. Derivation of virial coefficients using different equations of state, as studied by students of physical chemistry, are discussed. The Redlich-Kwong equation and the Gibbons-Laughton modification are used.

Teaching students of physical chemistry about the thermodynamics of mixing real gases is discussed. The discussion covered is designed to follow in a continuum coverage of ideal gas mixtures. It will draw on the knowledge they already have of gases and intermolecular forces and will connect to newly learned topics. The goal is to impress upon students that gas-phase thermodynamics is an engaging, vital topic that can test understanding of molecular behavior. Topics include Gibbs energy of mixing real gases and excess thermodynamic functions for binary mixtures.

Use of KaleidaGraph in the physical chemistry teaching laboratory is discussed. Nonlinear least-squares can be achieved using microcomputer data analysis programs. Advantages and limitations of KaleidaGraph from Synergy Software (Reading, PA) are listed.

Electrochemical thermodynamics can be taught to honors chemistry advanced-placement, first-year college students and even first-year high-school classes using guided discovery, entropy analysis, and galvanic cells. Students are often shown the Gibbs free energy relationship without an explanation of its basis. The foundation is thus shaky and conceptual misunderstandings arise.

A simple method of determining heat engine efficiency, temperature-entropy (TS) diagrams, has been used to help clear up confusion around the Carnot cycle and the efficiency of heat engines, as presented in physical chemistry textbooks. Only the Carnot cycle has the efficiency given by the classic equation. Reversible heat engines operate between the same two temperatures using other cycles have lower efficiency. Even though thermodynamics is emphasized less now than in the past in chemistry, these topics are still staples in physical chemistry textbooks. Coupling a Stirling cycle with a regenerator is covered.

Orbital plots can be set up by physical chemistry students using Gnuplot, a free many-platform general-purpose easy-to-use plotting program. There are various ways of displaying the one-electron hydrogen orbitals. For Gnuplot syntax for specifying a plot involves writing a plotting file for an orbital by transcribing the analytical form of the function to be plotted. Skills learned may be used elsewhere as well. It is good for students to be knowledgeable about Gnuplot because it is found in so many places on so many kinds of computers. It can be run through a Web page interface. Two- and thre-dimensional and contour plots are discussed.

Students of physical chemistry may use spectral experiments and vibrational analysis to study C(sub.60). An explanation of the drastic reduction in the numbers of observed IR and Raman bands in C(sub.60) is presented, and the basis in known structure for predicting the numbers is discussed. The molecule in question has the form of a regular truncated icosahedron of 20 hexagonal and 12 pentagonal faces and exhibits only 4 IR and 10 Raman bands. Topics include classification of normal vibrations into symmetry species, IR and Raman selection rules, and the number of normal vibrations in each symmetry species. The correlation method as applied to vibrational spectra of C(sub.60) and other fullerenes is discussed. Chemistry students should apply the correlation method to predict numbers of IR and Raman-active bands for a number of fullerenes. They should use molecular models made of paper, folding them and taping them together. Data is given.

Undergraduate students of physical-organic chemistry can learn about chemical instrumentation through use of photoacoustic calorimetry (PAC), which gives direct measurement of energy released nonradiatively after photostimulation. Two separate studies that show different interpretations of data collected by the same laboratory procedures and hardware for discrete chemical systems are presented. Only a digital oscilloscope, a nitrogen laser, a transducer, and a joulemeter or another transducer are needed.

The correctness of lack thereof of the concept that absolute temperature is always positive and that a negative value violates laws of thermodynamics is discussed. The absolute temperature concept has been based on the second law. It is shown that although in general absolute temperature can have only positive value, particular cases where only a finite number of energy levels are available can have negative values.

Moth balls or other products made of para-dichlorobenzene can be used in the chemistry classroom in a sealed container (some safety precautions are called for) to show students that crystals appear in the container in a warm atmosphere. An ice cube on an inverted jar is used. To show evaporation and condensation of liquid water and food coloring can be placed in an inverted closed jar with an ice cube on it. Sublimation illustrations are given. Odor perception and its use to demonstrate molecules traveling in gas are discussed.

Stoichiometry is a difficult subject to teach secondary school students but it is essential for understanding qualitative and quantitative chemical reactions. It is therefore essential that teachers design and use appropriate strategies to address these difficulties and to help students become conceptual problem solvers. A new study of students' problem solving strategies classifies them into three categories: correct, incorrect and incomplete strategies. Details of the study are further presented.

This article is an account of author's scientific achievements in physical chemistry teaching and research from his student years to the academic pursuits. Author discusses his works in chemical kinetics, molecular spectroscopy, and reaction dynamics.

Student perspectives on small-group learning in physical chemistry have been investigated at a university in an action research project. The project gave insight into how and why small-group learning gives positive outcomes as it builds community. The goals were to learn what small-group learning activities meant to the students, how the activities could be improved, and how perception of small-group learning had changed for students. Cooperative and collaborative learning environments are discussed in literature on group learning, but this project did not distinguish, as the type of task and how it is set up by the teacher would be determinants.

An undergraduate student of physical chemistry or a research student in electrochemistry can perform realistic linear-sweep numerical simulation of a curve reflecting what could be an actual situation in the laboratory with a newly developed method. The reverse procedure can be used to estimate electrochemical parameters. Students can get a feeling of how chemical quantities, among them transfer coefficients of exchange current densities and operating parameters, will affect measurement outcome. Teachers of electrochemical kinetics and those involved in metal deposition may be especially interested. The linear-sweep voltammetric (LSV) method applies a potential ramp using a potentiostat.

Luminescence quenching can be used in microemulsion studies and students of chemistry can use a probe method in luminescence experiments to study slow microemulsion dynamics in detail and to identify entropy as the quantity responsible for this behavior, which they will find unusual. A broad range of topics can be covered, among them kinetics, thermodynamics, statistics, quantum mechanics, and aspects of soft condensed matter.

Molecular photography can be used in the undergraduate chemistry laboratory for identification of functional groups using scanning tunneling microscopy. Easy-to-use scanning probe microscopes (SPMs) can have an important role acting as atomic or molecular cameras. Students not only take snapshots of atoms of bare surfaces but also identify chemically significant portions of molecular adsorbates placed on the surfaces. Students feel empowered as they obtain visual evidence for concepts that have seemed abstract.

Contact angle goniometry can be used by undergraduate physical chemistry students as a tool for surface tension measurements of solids, using the Zisman plot method. Accurate equipment that is not expensive is available. Commercial tensiometers, Wilhelmy balances and contact angle goniometers can be used, as can some other instruments that can be cheaply put together. The method of determining Young's contact angle, the Zisman plot, and a simple and dependable group method of obtaining surface tensions of a variety of solids are discussed.

A streamlined approach to solving complex and simple kinetic systems analytically has been developed for use in teaching students of chemistry. The material is presented in a simple and unified way so as to give firm foundation for more complex kinetic examples. A set of simple polynomial equations are to be used instead of solving simultaneous ordinary differential equations. Derivation of the rate expression for chemical reaction schemes involves mathematics significantly and some teachers are not comfortable with it. Topics discussed include Laplace transforms defined and applied to unimolecular transformations and rate equations for elementary steps.

Students can be taught about light scattering to help them learn about basic principles. Students tend to forget the fact that static light scattering is based in thermodynamics they learned in Freshman chemistry and physical chemistry. The relationships among osmotic pressure, the ideal gas law, and the fundamental theory of static light scattering are discussed. Light scattering can be used to apply wave interference concepts. Linearization and data fitting require some choices.

Chemical kinetics in constant-pressure systems is discussed. A treatment that can easily be extended to systems in which several reactions occur is presented. It is restricted to nonflow systems. Examples with implications for the material normally covered in constant-volume kinetics are given. The constant-volume case cannot be specialized to the constant-pressure case, but the latter case can be reduced to the former by specifying certain parameters.