This module is designed to give the learner an understanding of the nature of light and how its properties are used in the design of spectrophotometers. Problems promote the use of spectrophotometers in qualitative analysis, the optical elements used in a monochromator, and the physical properties of the prism and the diffraction grating. Other…

This course presents the student with a performance approach to biology. Each technique is covered in standard lecture format and in guided, independent laboratories. Examinations and grading are competency-based and require knowledge of both the use and limitations of the techniques. (BB)

This article describes how a gas chromatograph may be used to determine the amount of carbon dioxide in exhaled air. The experiment has been used as part of a demonstration exercise at a local science fair and proved of interest to all age groups. (Author/BB)

Shows how the Archimedes method is used to determine the density of a single crystal of ammonium oxalate monohydrate. Also shows how to calculate the density of other chemicals when they are available as single crystals. Experimental procedures and materials needed are included. (JN)

Reports a consecutive first-order reaction for which the concentrations of reactant, intermediate, and products can be determined simulataneously. This reaction is the epoxidation of 2,5-di-tert-butyl-1,4-benzoquinone (I) by alkaline hydroperoxidation using tert-butyl hydroperoxide and benzyltrimethylammonium hydroxide (Triton B) catalyst.…

Explains an experiment in which the rotation of a patch of skin on a tadpole results in a frog with rotated spots, proving that the spot pattern is determined long before it becomes visible. Procedures used are included. (DH)

Background information, procedures used, and results obtained are provided for an experiment in which a phase diagram is determined using a differential scanning calorimeter. Commercial samples of D-camphoric anhydride (Eastman Kodak) and D,L-camphoric anhydride (Aldrich) were used in the experiment. (JN)

Background information, procedures used, and typical results obtained are provided for an experiment in which students determine and compare the Arrhenius activation energies (Ea) for the hydrolysis of salicin. This reaction is subject to catalysis both by acid and by the enzyme emulsin (beta-d-glucoside glycohydrolase). (JN)

Shows that nitric acid can be used as a rapid, versatile, and economical oxidant for selected organic substances. The experiments (with background information, procedures, and results provided) require one three-hour laboratory period but could serve as open-ended projects since substrates not described could be oxidized. (JN)

Describes an experiment which offers a simple means of generating the liquidus curve of a temperature-composition diagram for a binary mixture of volatile liquids. Includes background information, materials list, procedures used (which can be accomplished by beginning organic chemistry students), and typical results obtained. (JN)

Describes this reaction sequence involving reactivity and synthesis of heterocycles: (1) synthesis of 2,4,6-triphenylpyrylium tetrafluoroborate, II; (2) its reaction with nucleophiles; (3) reaction of pyrylium salt II with a primary amine (benzylamine, p-methoxybenzylamine, and furfurylamine) to form the N-substituted-2,4,6-triphenylpyridinium…

Errors in determining the effectiveness of mouthwashes, disinfectants, and other household products as antibacterial agents may result from using broth cultures and/or irregularly shaped bits of filter paper. Presents procedures for a better technique and, for advanced students, two additional procedures for introducing quantitative analysis into…

Reports results in the attempted synthesis of the ethyl ester hydrochlorides of 21 common L-amino acids. Procedures used in the synthesis are outlined. (JN)

Background information and experimental procedures are provided for the multistep synthesis of frontalin. The experiment exposes students to a range of practical laboratory problems and important synthetic reactions and provides experiences in working on a medium-size, as well as a relatively small-size scale. (JN)

Describes a series of experiments (requiring six hours/week for six to eight weeks) involving the synthesis and methanolysis of substituted benzyl tosylates. The experiments provide students with experiences in kinetic data manipulation and an introduction and firm basis for structure-activity relationships and solvent effects in organic…