Foundations of Chemistry最新文献

Spectroscopy is a scientific topic at the interface between Chemistry and Physics, which is taught at high school level in relation with its fundamental applications in Analytical Chemistry. In the first part of the paper, the topic of spectroscopy is analyzed having in mind the well-known Johnstone’s triangle of chemistry education, putting in evidence the way spectroscopy is usually taught at the three levels of chemical knowledge: macroscopic/phenomenological, sub-microscopic/molecular and symbolic ones. Among these three levels, following Johnstone’s recommendations the macroscopic one is the most useful for high school students who learn spectroscopy for the first time. Starting from these premises, in the second part of the paper, we propose a didactic sequence which is inspired by the historical evolution of spectroscopic instruments from the first spectroscopes invented by Gustav Kirchhoff and Robert Bunsen in 1860 to the UV–vis spectrophotometers which became common since the 1960s. The idea behind our research is to analyze the conceptual advancements through the history of spectroscopy and to identify the key episodes/experiments and spectroscopic instruments. For each of them, a didactic activity, typically an experiment, is then proposed underlining the relevant aspects from the chemistry education point of view. The present paper is the occasion to reflect on the potentialities of an historical approach combined with a laboratorial one, and to discuss the role of historical instruments and related technological improvements to teach spectroscopy.

The way of thinking of mathematicians and chemists in their respective disciplines seems to have very different levels of abstractions. While the firsts are involved in the most abstract of all sciences, the seconds are engaged in a practical, mainly experimental discipline. Therefore, it is surprising that many luminaries of the mathematics universe have studied chemistry as their main subject. Others have started studying chemistry before swapping to mathematics or have declared some admiration and even love for this discipline. Here I reveal some of these mathematicians who were involved in chemistry from a biographical perspective. Then, I analyze what these remarkable mathematicians and statisticians could have learned while studying chemical subjects. I found analogies between code-breaking and molecular structure elucidation, inspiration for statistics in quantitative analytical chemistry, and on the role of topology in the study of some organic molecules. I also analyze some parallelisms between the way of thinking of organic chemists and mathematicians in terms of the use of backward analysis, search for patterns, and use of pictures in their respective researches.

Slater’s method is an integral part of the undergraduate experience. In actuality, Slater’s method is part of an atomic model and not simply a set of rules. Slater’s rules are a simple means for computing the effective nuclear charge experienced by an orbital. These rules are based on the shell-like structure of the Slater atom in which outer shell electrons are incapable of shielding inner electrons. Slater’s model provides a qualitative description of the valence electrons in multi-electron atoms with tremendous ease. The model is useful for explaining atomic properties such as ionisation energy, electron affinity and atomic radius qualitatively. Slater’s rules also correctly reproduce the Madelung rule of filling and the ionisation sequence (4s before 3d); however, these rules are not able to reproduce the anomalous configurations of atoms such as Cr and Cu. It is found that the atomic properties that Slater’s model reproduces are all related to the exponential decay factor of the Slater orbital. We find—from estimating the polarity of a diatomic molecule using a simple model—that molecular polarity is related to the difference in the exponential decay factors of the valence orbitals of the two atoms, implying that the decay factor acts as the electronegativity of the atom.

It is widely recognized that conceptual and theoretical innovations and the employment of new instruments and experimental techniques are important factors in explaining the growth of scientific knowledge in chemistry. This study examines another dimension of research in chemistry, collaboration and co-authorship. I focus specifically on Theodore Richards’ career and publications. During the period in which Richards worked, co-authorship was beginning to become more common than it had been previously. Richards was the first American chemist to be awarded a Nobel Prize and he was at the forefront in this new trend in chemistry. He collaborated more than was typical for his time, with many scientists, in different sized groups, and he often had persistent collaborative relationships, extending over a number of years. Further, it appears that these collaborations benefited Richards, his collaborators, and the field of chemistry as a whole.

Compelling evidence is presented that Glauber worked as a laborator (laboratory assistant) for Landgrave Georg of Hesse-Darmstadt from 1632/33 till he was appointed apothecary in Giessen in 1635. During this time, he was also used as laborator by the landgrave’s personal physician, Helwig Dieterich. Glauber became a famous chemist, whose alchemical secrets were keenly solicited by King Frederik III of Denmark, Queen Christina of Sweden, and, according to the 1662 diary of Ole Borch, King Charles II of England. A 1689 letter to Queen Christina contains detailed descriptions of Glauber’s alkahest, his decomposition and redintegration of saltpeter, and his ‘most secret sal armoniacum’, which is interpreted here for the first time.

Théophile De Donder, a Belgian mathematician born in Brussels, elaborated two important ideas that created a bridge between thermodynamics and chemical kinetics. He invented the concept of the degree of advancement of a reaction, and, in 1922, he provided a precise mathematical form to the already known chemical affinity by translating Clausius’s uncompensated heat into formal language. These concepts merge in an important inequality that was the starting point for the formalization of non-equilibrium thermodynamics. The present article aims to reconstruct how De Donder elaborated his ideas and developed them by exploring his teaching activity and its connection with his scientific production. Furthermore, it emphasizes the role played by the discussions with his disciples who became his collaborators. The paper analyzes De Donder’s efforts in participating in the second Solvay Chemistry Council in 1925 to call the attention of chemists to his mathematical approach. We explain why his work did not receive much attention at the time, and how, despite this, his formalization of chemical affinity became the basis for the birth of the so-called Brussels school of thermodynamics.