Considers the thermodynamic limitation to the efficiency with which light energy can be converted into work, indicating that no single chemical system converting solar energy into useful work can be very efficient. Also indicates that if solar energy is absorbed as heat for heating purposes, it is almost completely used. (JN)

Discusses the nature of experimental resonance energy, explaining how its magnitude depends upon choice of reference molecules from which bond energies are derived. Also explains how it can be evaluated more simply, without recourse to bond energies, as enthalpy change for a reaction predetermined by choice of reference molecules. (JN)

Analytical chemistry deals with the qualitative and quantitative identification, characterization, and measurement of the chemical species present in a sample. A description of and comments on preparing for a career in this branch of chemistry are provided. (JN)

Suggests polymer topics for study in inorganic chemistry courses. Commercial materials (including list of inorganic compounds utilized in polymer industry), anchored metal catalysis, polymers modified or formed by coordination, polysiloxanes, phosphazene or phosphonitrilic halide polymers, and hetergeneous polymerization catalysts are considered.…

High school chemistry students begin the school year by reading and studying "The Double Helix" by James B. Watson. Rationale, objectives, and instructional strategies for this assignment are discussed. Sample discussion questions based on the book are included. (JN)

Discusses factors which control rate and orientation of free radical addition to alkenes. Although based primarily on results involving behavior of alkyl radicals, arguments developed apply to addition of atoms and hetero-radicals to olefins. (JN)

Discusses use of microcomputers for grading, simulating laboratory experiments, data collection, and for communicating with students. Database systems, word processing, and an electronic spreadsheet program are also considered. Programing tips for several of these areas are included. (JN)

Peroxides are unstable, shock-, thermal-, and friction-sensitive compounds whose sensitivity increases with concentration. In addition, peroxides can form in aging organic solvents and stored alkali metals. Cautions related to storage, use, and disposal of peroxides in the secondary school chemistry laboratory are discussed. (JN)

Provided are procedures and list of materials needed to demonstrate that the pressure inside a container with a porous surface can be changed due to the rate of diffusion of low molecular weight gases. Typical results obtained are included. (JN)

Background information, procedures, and typical results are provided for an experiment illustrating the potential of hydrated salts for solar energy storage. The experiment involves a demonstration often used to illustrate the ease with which some transition metal ions can change their coordination numbers. (JN)

Provided are experiments to acquaint students with basic spectrophotometer components and their functions, to use the instrument in an openended-experiment, and to use Beer's Law in several different ways. In addition, the detectability (tolerance) of the spectrophotometer with visual detection limits is provided as an optional activity. (JN)

Background information, procedures, and results are provided for an experiment in which lead-210 is separated from bismuth-210 and polonium-210 by means of solvent extraction of their diethyldithiocarbamate complexes. The method involves a simple extraction procedure which allows complete separation of lead-210 from commercially available…

The separation of lead and bismuth by chelate solvent extraction is of interest because of the simplicity which the use of radiotracers allows in its demonstration. Theoretical background information, procedures, materials needed, and typical results are provided for an experiment involving the extraction. (JN)

Although determination of phosphorus is important in biology, physiology, and environmental science, traditional gravimetric and colorimetric methods are cumbersome and lack the requisite sensitivity. Therefore, a derivative activation analysis method is suggested. Background information, procedures, and results are provided. (JN)

High performance liquid chromatography (HPLC) is used to separate and quantitate beta-carotene, chlorophyll a, and chlorophyll b originating from collard greens. Experimental procedures used and typical results obtained are discussed. (JN)