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…

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…

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…

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…

As simple and ubiquitous redox-active organic molecules, quinones participate in diverse electron transfer processes in chemistry and biological systems for energy transformation and signal transduction. We introduce here a practical exercise to study the redox potentials of benzoquinone and its two derivatives by combining the electrochemistry…

Fundamentals of Macroscopic Chemical Analysis is a newly developed foundation-level course that integrates concepts from traditional physical and analytical chemistry courses. The course was designed to serve majors in chemistry, biochemistry, and biology as well as pre-health professional students. The main goal of this course is to develop the…

Molecules and Computer: Chemistry Calculations in Class (MC[superscript 4]) is a computational laboratory intended for final-year high school or undergraduate students. The topic is the antioxidant potential of anthocyanidins, which is chemically related to their radical scavenging action via the mechanism of hydrogen atom transfer (HAT). This…

Minimizing the energy consumption of desalination processes is an important goal for augmenting freshwater production and mitigating water scarcity. Chemical, civil, mechanical, and environmental engineering students can derive and analyze the energy consumption of desalination processes by applying engineering fundamentals such as thermodynamics,…

The change in enthalpy of a chemical reaction conducted at constant pressure is equal to the heat of the reaction plus the nonexpansion work of the reaction, ?H = qP + w[subscript additional]. After deriving that relationship, most general and physical chemistry textbooks set w[subscript additional] = 0 to arrive at the claim that ?H = qP, and…

In this article, we use a simple lattice model to illustrate the concepts of entropy, free energy, and thermodynamic equilibrium from a microscopic perspective. These physical concepts are based on elementary knowledge of discrete probability distribution and weighted average. Calculations about this model involve basic algebra and counting, which…

The use of free energy plots to understand the concept of thermodynamic equilibrium has been shown to be of great pedagogical value in materials science. Although chemical equilibrium is also amenable to this kind of analysis, it is not part of the agenda of materials science textbooks. Something similar is found in chemistry branches, where free…

The Hofmeister series is a recurring trend that ranks ions' abilities to influence various aqueous processes in solution. Herein, a set of project-based experiments was developed for students in an upper-level physical chemistry laboratory to investigate the specific ion effects on the thermodynamics of caffeine partitioning between aqueous and…

Spontaneity criteria for processes with useful (especially electrical) work have been discussed based on total differentials of thermodynamic functions. Reaction Gibbs energy ([Delta][subscript r]G) and electrochemical reaction Gibbs energy ([Delta][subscript r]G~) have been juxtaposed. Three-dimensional graphs showing the dependencies of…

A versatile and portable apparatus was developed to demonstrate exciting visual displays of catalytic phenomena that introduce basic concepts in catalysis, renewable energy, and chemical safety, in order to pique scientific curiosity in a variety of audiences including middle and high school students, undergraduate and graduate students, and the…

Many types of batteries power an ever-growing number of devices. Electrochemical devices like batteries and fuel cells can, in principle, exceed Carnot efficiency for energy conversion. In this novel laboratory experiment, students explore the partitioning of the enthalpy change of a battery's electrochemical reaction between useful electrical…