Foundations of Chemistry最新文献

In this contribution, the role of epistemology in understanding quantum chemistry is discussed. Quantum chemistry is the study of the behavior of atoms and molecules using the principles of quantum mechanics. Epistemology helps us evaluate claims to knowledge, distinguish between justified and unjustified beliefs, and assess the reliability of scientific methods. In quantum chemistry, the epistemology of knowledge is heavily influenced by the mathematical nature of quantum mechanics, and models can be tested, proven, and validated through experimentation. This paper also discusses key concepts used in quantum chemistry, such as the wave-particle duality of matter and the uncertainty principle. This work utilizes Kant’s philosophy of science to frame debates and discussions in quantum chemistry, particularly with regard to the interplay between empirical observation and theory. Additionally, the text explores how Kant’s ideas about the role of the mind in constructing our understanding of the world can help us comprehend the counterintuitive phenomena of quantum mechanics and its applications in quantum chemistry theory.

From organic synthesis to quantum chemical calculation, chemists interact with chemical substances in a wide variety of ways. But what even is a chemical substance? My aim is to propose a notion of chemical substance that is consistent with the way in which chemical substances are individuated in chemistry, addressing gaps in previous conceptions of chemical substance. Water is employed as a case study to develop the account, not only because it is a familiar example of a chemical substance, but also because its structural peculiarities make it an ideal test case for drawing out potential issues and limitations. Examining four distinct views of chemical substance—the microstructural, thermodynamic, purification, and a functional/relational account—I conclude that each has considerable drawbacks when used as a standalone concept. However, these accounts are not rendered obsolete, but are combined into a semi-pluralist conceptual patchwork. My interactive account of chemical substance is consistent with existing substance descriptions and chemical practice.

J. Willard Gibbs derived the following equation to quantify the maximum work possible for a chemical reaction

({text{Maximum work }} = , - Delta {text{G}}_{{{text{rxn}}}} = , - left( {Delta {text{H}}_{{{text{rxn}}}} {-}{text{ T}}Delta {text{S}}_{{{text{rxn}}}} } right) {text{ constant T}},{text{P}})

∆H_rxn is the enthalpy change of reaction as measured in a reaction calorimeter and ∆G_rxn the change in Gibbs energy as measured, if feasible, in an electrochemical cell by the voltage across the two half-cells. To Gibbs, reaction spontaneity corresponds to negative values of ∆G_rxn. But what is T∆S_rxn, absolute temperature times the change in entropy? Gibbs stated that this term quantifies the heating/cooling required to maintain constant temperature in an electrochemical cell. Seeking a deeper explanation than this, one involving the behaviors of atoms and molecules that cause these thermodynamic phenomena, I employed an “atoms first” approach to decipher the physical underpinning of T∆S_rxn and, in so doing, developed the hypothesis that this term quantifies the change in “structural energy” of the system during a chemical reaction. This hypothesis now challenges me to similarly explain the physical underpinning of the Gibbs–Helmholtz equation

({text{d}}left( {Delta {text{G}}_{{{text{rxn}}}} } right)/{text{dT}} = - Delta {text{S}}_{{{text{rxn}}}} left( {text{constant P}} right))

While this equation illustrates a relationship between ∆G_rxn and ∆S_rxn, I don’t understand how this is so, especially since orbital electron energies that I hypothesize are responsible for ∆G_rxn are not directly involved in the entropy determination of atoms and molecules that are responsible for ∆S_rxn. I write this paper to both share my progress and also to seek help from any who can clarify this for me.

The new mathematical connection of De Donder’s differential entropy production with the differential changes of thermodynamic potentials (Helmholtz free energy, enthalpy, and Gibbs free energy) was obtained through the linear sequence of equations (direct, straightforward path), in which we use rigorous thermodynamic definitions of the partial molar thermodynamic properties. This new connection uses a global approach to the problem of reversibility and irreversibility, which is vital to global learners’ view and standardizes the linking procedure for thermodynamic potentials (Helmholtz free energy, enthalpy, and and Gibbs free energy)—preferably to the sensing learners. It is shown that De Donder’s differential entropy production in an isolated composite system is equal to the differential change in total entropy and that De Donder’s equation agrees with Clausius’ inequality. The useful work of the irreversible process is discussed, which with the decrease of irreversibility tends towards the hypothetical maximum useful work of the reversible process.

Graphical abstract

Hydrogen is troublesome in any periodic table classification. This being so it may as well be placed in a position that confers desirable attributes to the arrangement of the elements, while notionally recognising its lineage to the group 1 alkali metals and the group 17 halogens. Since the noble gases bridge the halogens and the alkali metals, and hydrogen encompasses the transition from the alkali metals to the halogens, there is more to the idea of hydrogen over helium.

Hydrogen…seems to claim an exceptional position (Meyer 1870, p. 357)

The real voyage of discovery consists not in seeking new lands but in seeing with new eyes (Proust 1927, p. 559)

The 2016 Royal Society of Chemistry’s report Future of the Chemical Sciences presents four different scenarios for the future of chemistry: chemistry saves the world; push-button chemistry; a world without chemists; and free market chemistry. In this paper we ethically assess them. If chemistry is to solve many of the greatest challenges facing the contemporary world, prioritization of research topics will need to be done explicitly on the basis of moral values, ​​such as solidarity and equity, but also environmental justice, which will have to be central in determining a research agenda for chemistry. The decentralization of chemistry will also present ethical challenges to the research standards established by the scientific community. Ethical education in chemistry may help counteract these risks. We also argue that if chemistry and its subdisciplines are to fulfil their goal of generating knowledge and helping us solve the great challenges of the contemporary world, then it is ethically imperative that scientists from different disciplines be more open to interdisciplinary work. Finally, if the future of chemistry is in free market forms, then it is necessary that we pay more attention to the possible risks that this model has. We call attention to two: first, it is likely that problems that affect the lowest income countries or the most disadvantaged sectors of society, who do not have the means to pay for some of the goods and services, will not be addressed; second, the free market tends to foster unsustainable forms of development.

This paper proposes a theoretical approach to discuss the relations among reality, chemists’ interactions with it, and the resulting interpretation and representation of the acquired scientific knowledge. Taking into account that such relations are of semiotic nature, this paper aims at discussing in the light of Peirce’s theory of signs different descriptions of chemical activity and chemical education proposed by Alex Johnstone and elaborated by other science educators. In order to discuss the contributions and limitations of the proposed theoretical framework, and considering its potential interest for chemical education, an example on the communication strategies for the content ‘vapour pressure’ found in twentieth-century general chemistry university textbooks is also presented.

The incompatibility within the context of modeling cannot be established simpliciter. The fact that modeling is understood as an activity whose representational power can only be partially established, may minimize the supposed existence of incompatible models. Indeed, it is argued from perspectivism that incompatibility can be dissolved, meaning that it becomes trivial or simply false due to the inherently pragmatic and partial nature of the act of representation and modeling. From this perspective, incompatibility can only be a consequence of a misunderstanding of the very nature of modeling and representation In this sense, in order to tackle this strategy at its root from perspectivism, we will first need to outline the maximal perspectivism thesis, attempting to identify the possible escape routes that perspectivism could find in order to explain incompatibility as an illusory incompatibility. Then, we will analyze Valence Bond Model and Molecular Model of covalent bonds, and we will conclude that the dissuasive strategies used to minimize and/or disregard incompatibility prove to be fruitless.

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.