Second part of an article reviewing structural formulas. (SL)

There is mounting evidence for the existence of the principle: syntropy--or "negative entropy"--through the influence of which forms tend to reach higher and higher levels of organization, order, and dynamic harmony. Presented at the Symposium on the Relationship between the Biological and Physical Sciences at Columbia University.…

Describes a computer program that allows undergraduate students to undertake nomenclature tutorials in organic chemistry, where user response is evaluated based on a set of rules that determine appropriate feedback. Design of the software is described, including the use of computer graphics, and results of students' evaluations are briefly…

Details ab initio crystal orbital calculations using all-trans-polyethylene as a model. Describes calculations based on various forms of translational symmetry. Compares these calculations with ab initio molecular orbital calculations discussed in a preceding article. Discusses three major approximations made in the crystal case. (CW)

In this article, the third part of a series, the results of ab initio polymer calculations presented in part 2 are discussed. The electronic structure of polymers, symmetry properties of band structure, and generalizations are presented. (CW)

Discusses the difficulties that some students have in understanding the concept of chemical reactions. Proposes that instructors try to consider the various difficulties during a chemistry course when students form their concepts of element conservation. (TW)

Discusses the variety of explanations in organic chemistry textbooks of a physical property of organic compounds. Focuses on those concepts explaining attractive forces between molecules. Concludes that induction interactions play a major role in alkyl halides and other polar organic molecules and should be given wider exposure in chemistry texts.…

Explains the structural organization of DNA by providing information on the primary, secondary, tertiary, and higher organization levels of the molecule. Also includes illustrations and descriptions of sign-inversion and rotating models for supercoiling of DNA. (ML)

Determined the factor structure of tasks which require students to visualize how diagrams should be drawn to represent effects of rotating three-dimensional structures about the three Cartesian axes. Results obtained from 149 English and 231 Singapore students show that visualization about X-, Y-, and Z-axes are factorially distinct. (DH)

Various typs of DNA are discussed. Areas considered include highly repetitive and satellite sequences, genes encoding, ribosomal RNA, histone protein genes, and dispersed repeated genes that jump. Regulated genetic misbehavior, structure and use of unique genes, and higher order complexities of chromosomes are also discussed. (JN)

Summarizes the structures, shapes, linkages, chain lengths, and physical and chemical properties of polymers, copolymers, and proteins with a background of knowledge of monomer units. (CC)

One application of modeling is studying the ways in which molecules fit together to form chemical compounds. Describes the forces acting between molecules and how three-dimensional graphical modeling is employed in developing rational principles for drug design. (JN)

To make material on Raoult's law more meaningful, students complete exercises on paper, in the laboratory, and with molecular models. Paper exercises give practice using the law; laboratory work illustrates behavior of real solutions; and models show relationships between properties of individual molecules and of matter in bulk. (JN)

Following a comparison of chain-growth and step-growth polymerization, focuses on the latter process by describing requirements for high molecular weight, step-growth polymerization kinetics, synthesis and molecular weight distribution of some linear step-growth polymers, and three-dimensional network step-growth polymers. (JN)

An integral equation for the s-wave bound-state solution is derived and then solved for a square-well potential. It is shown that the scattering solutions continue to exist at negative energies, and when evaluated at the energy of a bound state these solutions do reduce to the bound-state solution.