Keto-enol tautomerization is paramount to understanding the mechanisms involved in many organic reactions and biochemical transformations. Isomerization of an enol to a carbonyl compound is typically introduced during the discussion of the acid-catalyzed electrophilic addition of water to alkynes. The tautomerization of carbonyl compounds to enol…

The dissolution of cobalt­(II) chloride in an appropriate binary alcohol solvent yields an equilibrium mixture, consisting of the differently colored octahedral (pink in color) and tetrahedral (blue in color) cobalt­(II) coordination complexes, which can exhibit a brilliant and reversible pink-to-blue color transition over a ~10 °C window - i.e.,…

Under the appropriate conditions, oscillatory chemical reactions have the capacity to generate chemical waves and spatial patterns. Among these structures, Turing patterns are a distinct class that, to date, has not been commonly demonstrated in a classroom environment. We present here a novel, practical procedure for the demonstration of Turing…

A laboratory experiment in which [superscript 1]H NMR and UV-vis spectroscopies are applied to probe the temperature dependence of a monomer-dimer equilibrium involving a cyclopentadienone derivative is described and discussed. Details of the data analysis for extraction of equilibrium constants from the raw experimental data from both techniques…

Energy conversion devices such as fuel cells, metal-air batteries, and electrolyzers have been envisaged as possible solutions for cutting down the continuous accumulation of greenhouse gases resulting from the combustion of fossil fuel. The bottleneck reaction for these devices is the oxygen reduction reaction (ORR) occurring at the cathode. The…

Isothermal titration calorimetry (ITC) is the method of choice for thermodynamic binding profiling. As a label-free in-solution technique, ITC experiments do not require modified or immobilized proteins or ligands and hence can be performed under close-to-native environmental conditions. It directly follows the released heat of the molecular…

Periodicity in electronic molar entropy values has been shown on the basis of the electronic structures of the elements. Also, with the approximations discussed herein, one can estimate the electronic molar entropy without atomic spectroscopy results. All of this can be accomplished by showing the connection between the vector model of the atom…

An activity is described that uses simple materials and an easy-to-perform protocol to estimate the Curie temperature of nickel, which is the temperature at which nickel loses its ferromagnetism. To do so, an object made of nickel metal is heated with a lighter until it loses its ferromagnetism. The metal is allowed to drop into a beaker that…

The COVID-19 pandemic and its related restrictions forced the reorganization of learning methodology and gave a central role to remote learning. Laboratory experiments are the most affected activity, and several alternatives were described. This work proposes to create calculation tools by simply programming in Visual Basic of Excel to emulate the…

The acid-catalyzed dehydration of regioisomeric methylcyclohexanols is a classic organic chemistry experiment featured in a variety of laboratory textbooks and literature. The mechanistic details of this reaction have received an inconsistent and occasionally inaccurate treatment, wherein the reaction has been described as a mix of E1, E2-like,…

We describe an experiment in which students use research-grade instrumentation to collect gas adsorption data in triplicate in a single 3 h laboratory period. The experiment reinforces the thermodynamic concepts taught in upper level physical chemistry courses and hands-on experience with instrumentation used in research laboratories. The speed of…

The inexorable rise in atmospheric carbon dioxide impacts not only global warming but also the acidity of the ocean. Increasing ocean acidity causes a decline in carbonate (as it is protonated), which in turn will negatively impact the ability of calcifying marine organisms to build their calcium carbonate shells. A simple set of equilibrium…

In this laboratory experiment, students modify a series of surfaces and explore the effects of varying surface chemistry and texture on wettability by different probe liquids. Students begin by building a simple contact angle goniometer utilizing their mobile phone cameras. Next, they contrast the wettability of planar glass substrates…

A novel demonstration device for realizing the intuitive visual observation of the system's internal energy change is proposed. The device is safe, simple, and efficient, combining an infrared camera with a water bottle sprayer. With this setup, the changes of thermal images for air and helium during the compression and expansion processes were…

Under most conditions, a liquid mixture does not have long-range structural order and may be considered to be a homogeneous collection of molecules in random motion. However, if a single-phase critical mixture of a partially miscible liquid--liquid system is subjected to a small temperature jump into the two-phase region, then structural coherence…