ChemTexts

Abstract A guided, stepwise thermodynamic analysis of the ammonia synthesis reaction is presented in the form of a multipart student problem with an accompanying guided computational solution. The activity is designed to strengthen student understanding of chemical potentials ( µ ), Gibbs ( G ), and Helmholtz ( A ) free energies, and their quantitative connection to chemical equilibrium under dif…

Abstract Lithium-ion batteries (LIBs) dominate the electrochemical energy storage field currently, yet undergraduate materials science and engineering students often encounter LIB technology primarily via classroom studies. Despite having a fundamental knowledge of electrochemistry, still hands-on experience with cell construction, testing, and performance analysis is missing. This article descri…

Abstract The Chernobyl nuclear disaster of April 1986 released significant radioactive contamination by means of radionuclides across Europe, presenting unprecedented challenges to environmental, radiochemistry, human and veterinary medicine. Among the most effective countermeasures developed was ammonium iron hexacyanoferrate, a Prussian blue compound that efficiently binds radiocesium in the di…

Abstract The quasi-steady-state approximation of chemical kinetics consists of equating to zero the time derivatives of the concentrations of intermediate species in the rate equations. It is remarkably successful in simplifying those equations, but that does not imply that any conclusions drawn are correct. Singular-perturbation theory has proved effective in deciding such questions, but is not …

Abstract Galvani postulated the existence of animal electricity in 1791 after observing that touching the nerves and muscles of a skinned frog with an arc made of two different metals (e.g. Ag and Zn) caused convulsive movement. Alessandro Volta attributed the generation of electricity to the potential difference that arises when different metals come into contact ( metallic electricity , 1796). …

Abstract This article explores the historical case of the Pine Institute in Aquitaine (France) to examine whether resin chemistry between 1900 and 1970 can be regarded as a precursor to modern green and sustainable chemistry. By situating the Institute’s activities within broader scientific, economic, and ecological contexts, the study challenges the common perception that sustainability in chemi…

Abstract Painting, from its beginnings over 30,000 years ago, has been conditioned by the availability of pigments, whether mineral or synthesised by ingenious craftsmen and manufacturers. While the yellow (yellow ochre) and red (red ochre) colours from surface minerals and black from charcoal used in cave paintings (30,000–15,000 BC) were readily available, the blue of sky and water was the last…

Abstract This lecture text presents the chemical analysis used for the investigation of a suspected poisoning in clinical and forensic toxicology. Following the discussion of the huge number and structural diversity of toxic substances, typical indications of a poisoning are given, which derive from the case history, the site where the unconscious person or the corpse was found, clinical symptoms…

Abstract Tyrosinases (TYRs) are a family of copper-containing metalloenzymes that are present in all domains of life. TYRs catalyze the reactions that start the biosynthesis of melanin, the main pigment of the animal kingdom, and are also involved in the formation of the bright colors seen on the caps of mushrooms and in the petals of flowers. TYRs catalyze the ortho -hydroxylation and oxidation …

Abstract van’t Hoff and Clausius–Clapeyron equations correspond to chemical and phase equilibria, respectively, but the Clausius–Clapeyron equation can be also a result of the application of van’t Hoff equation to the liquid–vapor or solid–vapor phase equilibrium of pure substances. Moreover, the application of van’t Hoff to gas–liquid and solid–liquid equilibrium data makes it possible to obtain…

Abstract Neutron scattering is a very high-performance method for studying the structure and dynamics of condensed matter with similar approaches in wide ranges of space and time, matching dimensions in space from single atoms to macromolecules and in time from atomic vibrations over crystal phonons to low-lying transitions in the microwave range, and to motions of large molecular units. Concerni…

Abstract This lecture text focuses on surface forces and interactions in a liquid medium, with particular emphasis on the surface-surface interactions described by the DLVO theory, i.e., van der Waals attraction and electric double-layer repulsion. The text begins by describing the fundamental forces of nature, their connection to intermolecular interactions, and how the latter result in measurab…

Abstract In the last few years, 3D printing has evolved from its original niche applications, such as rapid prototyping and hobbyists, towards many applications in industry, research and everyday life. This involved an evolution in terms of equipment, software and, most of all, in materials. Among the different available 3D printing technologies, the light activated ones need particular attention…

Abstract Macrophages are cells of the innate immune system and represent an important component of the first-line defense against pathogens and tumor cells. Here, their diverse functions in inflammation and tumor defense are described, and the mechanisms, tools, and activation pathways and states applied are presented. The main focus is on the role and origin of reactive oxygen species (ROS), the…

Abstract This text is designed to give the reader a helping hand in writing a scientific paper. It provides generic advice on ways that a scientific paper can be improved. The focus is on the following ethical and non-technical issues: (1) when to start writing, and in what language; (2) how to choose a good title; (3) what should be included in the various sections (abstract, introduction, exper…