Describes a laboratory technique for quantitative analysis of caffeine by an isotopic dilution method for coupled gas chromatography-mass spectroscopy. Discusses caffeine analysis and experimental methodology. Lists sample caffeine concentrations found in common products. (MVL)

Described are the energetics involved in the formation of molecular hydrogen using concepts that should be familiar to students beginning the study of molecular orbital theory. Emphasized are experimental data on ionization energies. Included are two-electron atomic and molecular systems. (CW)

Defines and discusses activated complexes, transition species, and reaction intermediates in composite reactions. Stresses the importance of the precise use of language in science. (CW)

Describes a study of perceived difficulty of chemistry courses among secondary school and college students in Kenya. Concludes that organic chemistry may not be as difficult as many people believe. (CW)

Describes a simplified redox method for total iron analysis suitable for execution in a three-hour laboratory period by general chemistry students. Discusses materials, procedures, analyses, and student performance. (CW)

Describes a laboratory experiment to determine the rate law for a substitution reaction of a transition metal. Derives the corresponding rate law from the accepted mechanism for the reaction using the steady state approximation and determines the conditions under which the two agree. (CW)

Proposed is a flow-chart and related formulas to obtain expressions for the derivatives of the old thermodynamic function in terms of new variables, the new function and its derivatives, and derivatives of the old function, involving only measurable quantities. (CW)

Presents a review focusing on techniques and their application to the analysis of geological and inorganic materials that offer significant changes to research and routine work. Covers geostandards, spectroscopy, plasmas, microbeam techniques, synchrotron X-ray methods, nuclear activation methods, chromatography, and electroanalytical methods.…

Describes an experimental procedure to acquaint inorganic chemistry students with stereochemical concepts using tris-(2,3-butanediamine)cobalt(III). Notes two isomeric forms exist and both form metal chelates. Separation is accomplished by chromatography and analysis is by NMR and infrared spectroscopy. Provides spectra of isomers. (MVL)

Described is an analytical method that may be used to replace the more difficult, traditional approach for the analysis of silicates. It is argued that this method allows the use of smaller samples and is more sensitive than other techniques. (CW)

Presents four articles dealing with chaotic systems. Lists sources for nine demonstrations or experiments dealing with self-organization. Provides a vocabulary review of self-organization. Describes three chemical oscillator models. Discusses the role of chaos in flow systems. (MVL)

Discusses a student exercise which requires the optimizing of the charring and atomization temperatures by producing a plot of absorbance versus temperature for each temperature parameter. Notes that although the graphite furnace atomic absorption spectroscopy technique has widespread industrial use, there are no published, structured experiments…

Notes that the rigorous kinetic theory, based on the Boltzmann equation, does not yield exact results although some texts claim this to be so. Stresses that they should be presented as approximations with an indication that refinements in the values are possible. (MVL)

Discussed are selected application and future trends in supercritical fluid chromatography (SFC). The greatest application for SFC involves those analytes that are difficult to separate using GC or LC methods. Optimum conditions for SFC are examined. Provided are several example chromatograms. (MVL)

Attempts to show that in the closed loops of cyclic structures the protons situated in conic regions above and below the ring will be shielded. Uses the diamagnetic and air stable octahedral tin(IV) complexes of porphyrins for study. Notes complexes crystallize easily and offer spectacular purple colors. (MVL)