A new method for obtaining Russell-Saunders terms of atomic configurations is reported. This new method is significantly different from, while at the same time complementary to, previously published methods for obtaining atomic terms. This novel procedure is elicited by the method used to determine the splitting of S, P, D terms in weak ligand…

An undergraduate first-semester general chemistry laboratory experiment introducing face-centered, body-centered, and simple cubic unit cells is presented. Emphasis is placed on the stacking arrangement of solid spheres used to produce a particular unit cell. Marbles and spherical magnets are employed to prepare each stacking arrangement. Packing…

In this exercise, students apply a combination of techniques to investigate the impact of metal identity and ligand field strength on the spin states of three d[superscript 5] transition-metal complexes: Fe(acac)[subscript 3], K[subscript 3][Fe(CN)[subscript 6]], and Ru(acac)[subscript 3], where acac[superscript -] is acetylacetonate. Students…

Formula unit (or molecular) volume, "V[subscript m]", is related to many thermodynamic and physical properties of materials, so that knowledge of "V[subscript m]" is useful in prediction of such properties for known and even hypothetical materials. The symbol "Z" represents the number of formula units in a crystallographic unit cell; "Z" thus…

For most materials, the solid at and near the triple-point temperature is denser than the liquid with which it is in equilibrium. However, for water and certain other materials, the densities of the phases are reversed, with the solid being less dense. The profound consequences for the appearance of the "pVT" diagram of one-component materials…

Changes in entropy can "sometimes" be interpreted in terms of changes in disorder. On the other hand, changes in entropy can "always" be interpreted in terms of changes in Shannon's measure of information. Mixing and demixing processes are used to highlight the pitfalls in the association of entropy with disorder. (Contains 3 figures.)

The acid ionization constant, K[subscript a], of acetic acid and the base ionization constant, K[subscript b], of ammonia are determined easily and rapidly using a datalogger, a pH sensor, and a conductivity sensor. To decrease sample preparation time and to minimize waste, sequential aliquots of a concentrated standard are added to a known volume…

X-ray fluorescence (XRF) data from an energy-dispersive XRF instrument were used to investigate the chlorine K[alpha] and K[beta] peaks in several group 1 salts. The ratio of the peak intensity is sensitive to the local chemical environment of the chlorine atoms studied in this experiment and it shows a periodic trend for these salts. (Contains 1…

An open-access, Web-based mnemonic game is described whereby introductory chemistry knowledge is tested using mahjong solitaire game play. Several tile sets and board layouts are included that are themed upon different chemical topics. Introductory tile sets can be selected that prompt the player to match element names to symbols and metric…

Many students find product prediction in ozonolysis reactions of alkenes and alkynes difficult, and they often have greater difficulty discerning the starting compounds when presented with ozonolysis products. The mnemonic device suggested here can help students figure out what the ozonolysis product (or products) will be. Once mastered, this…

We present a demonstration involving the oxidative photobleaching of a raspberry juice dye under visible laser light irradiation using the semiconductor titanium dioxide. A plausible interpretation of the phenomenon is discussed that aids in the understanding of semiconductor energetics and the nature of light. (Contains 2 figures.)

To diversify the measurement techniques of Avogadro's number in physics teaching, I propose a simple acoustic method for the experimental determination of Avogadro's number based only on the measurement of the speed of sound in metals, provided that their Debye temperatures are known. (Contains 2 figures.)

Portable Energy-Dispersive X-Ray Fluorescence (XRF) analyzers have undergone significant improvements over the past decade. Salient advantages of XRF for elemental analysis include minimal sample preparation, multielement analysis capabilities, detection limits in the low parts per million (ppm) range, and analysis times on the order of 1 min.…

Saturation transfer difference (STD) NMR has emerged as one of the most popular ligand-based NMR techniques for the study of protein-ligand interactions. The success of this technique is a consequence of its robustness and the fact that it is focused on the signals of the ligand, without any need of processing NMR information about the receptor…

This experiment describes a method for cyclohexene oxidation to "trans"-1,2-cyclohexanediol using "p"-toluenesulfonic acid ("p"-TsOH) as promoter and hydrogen peroxide as oxidant in a biphasic system. This method allows conversions up to 97.9% (monitored by [superscript 1]H NMR). "trans"-1,2-Cyclohexanediol was not easily separated from the…