A classroom demonstration detailing the procedure for the separation of a ternary mixture consisting of intensely colored compounds using silica gel column chromatography is described. The audience can follow the compounds during their passage through the column as individual, colored bands while learning about different tools and techniques used…

The titration of HCl with NaOH has traditionally been used to introduce beginning chemistry students to the concepts of acid-base chemistry and stoichiometry. The demonstration described in this article utilizes this reaction as a means of providing students an opportunity to observe the dynamic motion associated with a swirling vortex and its…

Drops of oil in Mn(SO[subscript 4])(aq) and drops of the solution in oil show opposite effects when brought near a rare earth magnet. Oxygen, nitrogen, and air bubbles atop water show expected attraction, repulsion, and null behavior, respectively. Air bubbles atop aqueous Mn(SO[subscript 4]) show paradoxical behavior because the magnet's…

Measured magnetic susceptibilities of paramagnetic substances must typically be corrected for their underlying diamagnetism. This correction is often accomplished by using tabulated values for the diamagnetism of atoms, ions, or whole molecules. These tabulated values can be problematic since many sources contain incomplete and conflicting data.…

Nuclear magnetic resonance (NMR) spectroscopy is widely used by chemists. Furthermore, the use of NMR spectroscopy to solve structures of macromolecules or to examine protein-ligand interactions is popular. Yet, few students entering graduate education in biological sciences have been introduced to this method or its utility. Over the last six…

"If protons, quarks, and other elementary particles are too small to be seen, how do scientists know they exist? And if these particles do exist, how can one estimate their size, structure, and or their arrangement in atoms?" These are some of the most frequently asked questions by students who study atomic theory. Atomic structure is an important…

I describe how data pooling and data visualization can be employed in the first-semester general chemistry laboratory to introduce core statistical concepts such as central tendency and dispersion of a data set. The pooled data are plotted as a 1-D scatterplot, a purpose-designed number line through which statistical features of the data are…

Waste newspaper is pulped with acid and its cellulose is hydrolyzed. The resulting glucose syrup is fermented with yeast and distilled to give ethanol. The experiment highlights the potential of applied chemistry to confront problems of economic importance, that is, the effective utilization of biomass to reduce dependence on non-renewable…

Treatment of phenylacetic acid with 90% HNO[subscript 3] yields a product, I, whose observed melting point is 175-179 degrees C and whose equivalent weight is approximately 226 grams. Treatment of phenylacetic acid with 70% HNO[subscript 3] yields a product, II, whose observed melting point is 106-111 degrees C and whose equivalent weight is…

The aryl sulfonate ester, menthyl N-acetylsulfanilate, is synthesized from N-acetylsulfanilyl chloride and menthol in pyridine, then pyrolyzed (thermally decomposed) at reduced pressure. The volatile (elimination) products of the reaction are analyzed using gas chromatography, and the resulting product distribution is used to determine whether the…

This article describes the rapid, green synthesis of a biaryl compound (4-phenylphenol) via a Pd(0)-catalyzed Suzuki cross-coupling reaction in water. Mild reaction conditions and operational simplicity makes this experiment especially amenable to both mid- and upper-level undergraduates. The methodology exposes students to purely aqueous…

Seven p-nitrophenyl benzoate esters (p-nitrophenyl benzoate, p-nitrophenyl m-anisate, p-nitrophenyl p-anisate, p-nitrophenyl m-chlorobenzoate, p-nitrophenyl p-chlorobenzoate, p-nitrophenyl m-toluate, p-nitrophenyl p-toluate) were synthesized and characterized by students in a second-semester organic laboratory course. In a subsequent laboratory…

The cryophorus dramatically demonstrates the cooling effect of evaporation. This article describes some simple and easy-to-make cryophoruses, ideal for demonstrating evaporative cooling to students at all levels. The most dramatic effects occurred with cyclohexane and benzene, with water generally freezing more slowly. (Contains 4 notes, 2 tables,…

In this lab experiment, screen-printed electrode strips are used to illustrate the essential concepts of electrochemistry, giving students an opportunity to explore metal electrodeposition processes. In the past, metal electrodeposition experiments were seldom included in general chemistry labs because of the difficulty of maintaining separate…

A statistical analysis of multiple-choice answers is performed to identify anomalies that can be used as evidence of student cheating. The ratio of exact errors in common (EEIC: two students put the same wrong answer for a question) to differences (D: two students get different answers) was found to be a good indicator of cheating under a wide…