A model proposed by Rioux to explain Hund's rule is investigated. Although the largest contribution to the singlet-triplet splitting in the two-electron atomic systems is the nuclear attraction term, this arises from different optimum scale factors in the two states and that difference is driven by the electron-electron exchange term. The…

A general result for the integrals of the Gaussian function over the harmonic oscillator wavefunctions is derived using generating functions. Using this result, an example problem of a harmonic oscillator with various Gaussian perturbations is explored in order to compare the results of precise numerical solution, the variational method, and…

The changes that have taken place in the organic chemistry laboratory course since 1980s are reviewed with reference to the quantity and diversity of discovery-based experiments available to date. The data illustrates that significant progress is towards accomplishing dramatic changes such as the almost universal adoption of microscale, the use of…

The relationship between aromaticity and stability in molecules on the basis of quantities such as hardness and electrophilicity is explored. The findings reveal that aromatic molecules are less energetic, harder, less polarizable, and less electrophilic as compared to antiaromatic molecules, as expected from the electronic structure principles.

The plausible and frequently used explanation of the singlet and triplet wave functions for a two-electron system is presented. Its findings reveal that the antisymmetric triplet spatial wave function keeps electrons apart, while the symmetric singlet spatial wave function permits electrons to be close together.

Random-climb models enable undergraduate chemistry students to visualize polymer molecules, quantify their configurational properties, and relate molecular structure to a variety of physical properties. The model could serve as an introduction to more elaborate models of polymer molecules and could help in learning topics such as lattice models of…

The impact of biodiesel on classrooms and teaching laboratories has potential similar to country's energy security and could help introduce environmental concepts, thermodynamics, titrations, combustion and chemical reactions. While researchers are exploring new methods and approaches to alternative fuels and renewable energy, the educators could…

Middle or high school students celebrate Earth Day on April 22, 2007 by participating in the activity to separate commingled recyclable trash to simulate sorting in a recycling center. Students would gain an appreciation for recyclable trash, after it is taken to a recycling center and learn about properties of recyclables.

The safety and health hazards related to recycling of used rubber, due to the scarcity and high price of virgin rubber are reported. Various threats like stagnant water pools trapped in tires leading to diseases and ignited tires, which become very difficult to extinguish and generating smoke that is extremely detrimental to the environment, have…

The history behind the association of Avogadro's name related to the hypothesis that equal volumes of gases at constant temperature and pressure contain equal numbers of molecules is explored. The findings suggest that the index entry "Avogadro's Number" did not become common in American college texts until the 1930s and was rare in American high…

The concentration game can be used as a complete class or a portion of it to help reinforce the material being presented or for review sessions. An environmental chemistry class review is presented with the use of the concentration game.

Participation of environmental chemistry students in mock congressional hearings is described, as a means of helping them better develop their speaking and debating skills. The activity brings active learning principles into the classroom and greatly increases student participation in an otherwise traditional lecture course.

A new special-topics course on green chemistry would help students to critically evaluate policy decisions in an environmentally conscientious manner. The actively acquired knowledge would allow students to spread the word about green chemistry in the long term to the world, where they would pursue their future goals of life.

A multi-tool approach incorporating traditional lectures, multimedia learning objects, and a laboratory activity were introduced as the concepts surrounding hydrogen fuel-cell technology in college chemistry courses. The new tools are adaptable, facilitating use in different educational environments and address variety of learning styles to…

Examples of plastic solar-cell technology to illustrate core concepts in chemistry are presented. The principles of operations of a plastic solar cell could be used to introduce key concepts, which are fundamentally important to understand photosynthesis and the basic process that govern most novel optoelectronic devices.