Background information, materials needed, and procedures used are provided for potentiometric fluoride, halide, orthophosphate, and sulfate titrations. Typical results obtained are also provided for each type of titration. (JN)

Background information, procedures used, and typical results obtained are provided for a simple homogeneous precipitation preparation of chromium(II) acetate. (JN)

Assessed Venezuelan college freshmen's (N=709) level of formal or concrete operations and its correlation with performance in various courses. Findings show 84 percent were concrete; achievement in chemistry had the highest correlation with formal operations, and decreasing correlations occurred with mathematics, biology, biology lab,…

Four papers are reviewed. They include a description of how instructional modules and small group problem-solving (PS) in a second-year plant anatomy course produced excellent PS skills and various ideas on PS in the context of chemistry. Also reviews guided-design as a strategy to help develop PS skills. (JN)

Discusses direct chemical information that can be obtained from modern nuclear magnetic resonance (NMR) methods, concentrating on the types of problems that can be solved. Shows how selected methods provide information about polymers, bipolymers, biochemistry, small organic molecules, inorganic compounds, and compounds oriented in a magnetic…

Describes a convenient procedure, the Odd-Even Rule, for predicting the allowedness of forbiddenness of ground-state, pericyclic reactions. The rule is applied to a number of specific reactions. In contrast to the Woodward-Hoffman approach, the application to each reaction is always the same. (JN)

The design and use of an inexpensive thermistor thermometer is described. In addition to providing a rugged thermometer, using the instruments offers an opportunity to have students become familiar with new principles and techniques, such as principles of thermistors, the Wheatstone bridge, and the concept of calibration. (JN)

Because the names, interrelations, and oxidation levels of the organic compounds of phosphorus and sulfur tend to confuse students, a simple way to organize these compounds has been developed. The system consists of grouping them by oxidation state and extent of carbon substitution. (JN)

Describes an experiment that involves the extraction of lead from gasoline into an aqueous solvent using iodine monochloride reagent. This method (which avoids the aspiration of organic solvents) also illustrates the use of wavelengths other than the most sensitive wavelength and effects of flame stoichiometry and burner height upon absorbance.…

Background information, experimental procedures used, and typical results obtained are provided for an experiment that demonstrates the stereospecific arrangement of cyclopropyl halides to allylic halides. (JN)

Describes the use of phase transfer conditions to prepare a sulfur and phosphorus ylide. Background information and procedures are provided for the experiment (which can be completed in one three-hour laboratory period). (JN)

Describes the use of rubber hand-stamps to generate molecular pictures. These stamps (prepared with shapes of atoms and molecules at little cost by small, local print shops) can be used in creating pictures representing the microscopic state that can be linked to macroscopic descriptions for active conceptual exploration. (JN)

Provides procedures to measure the calcium concentration in fruit juice by atomic absorption. Fruit juice is used because: (1) it is an important consumer product; (2) large samples are available; and (3) calcium exists in fruit juice at concentrations that do not require excessive dilution or preconcentration prior to measurement. (JN)

Although it is a major synthetic reaction, the Wittig reaction has not been used in undergraduate laboratories due to the potential hazard and difficulty associated with the preparation/use of the strong bases needed to generate the required ylides. Procedures are presented for an experiment in which these difficulties are avoided. (JN)

Describes an experiment which shows: (1) how measurements of the reaction electromotive force for the cell (Pt/glass/NaCl(aq,m),buffer/AgCl/Ag/Pt) can be utilized in determining the absolute pH of the buffer; and (2) the demonstration of the use of the Debye-Huckel model of an electrolyte solution in solving an important electrochemical problem.…