Chemical explanations

The complex nature of coal as a molecular entity (2,3,24,25,35,37,53) has resulted ia the chemical explanations of coal combustion being confined to the carbon ia the system. The hydrogen and other elements have received much less attention but the system is extremely complex and the heteroatoms, eg, nitrogen, oxygen, and sulfur, exert an influence on the combustion. It is this latter that influences environmental aspects. 

By adopting a perspective from the philosophy of science I will attempt to cross levels of complexity from the most elementary chemical explanations based on electron shells to those based on ab initio methods. Such a juxtaposition is seldom contemplated in the chemical literature. Textbooks provide elementary explanations which necessarily distort the full details but allow for a more conceptual or qualitative grasp of the main ideas. Meanwhile the research literature focuses on the minute details of particular methods or particular chemical systems and does not typically examine the kind of explanation that is being provided. To give a satisfactory discussion of explanation in the context of the periodic table we need to consider both elementary and deeper explanations within a common framework. 

Treagust, D. F., Chittleborough, G., Mamiala, T. (2003). The role of submicroscopic and symbolic representations in chemical explanations. International Journal of Science Education, 25(11), 1353-1368. 

Self-as-explainer This involves the process by means of which chemical explanations are produced, and entails a consideration of what influences people s approaches to explaining things and events and of the way the process has, and does, function. This would be of importance to those who deal with have-cause-to-know chemistry , experts who deal with the general public on real-life issues... 

This is the framework of methodologies that can be used to conduct legitimate enquiries in a subject, meaning those which lead to the production of acceptable scientific knowledge. The natures of each of the types within the representational triplet and their relationships to each other provide an explanatory framework in respect of all chemical phenomena. The macro and submicro types of representation do so for the Group A curriculum at the desired qualitative level, whilst the addition of the symbolic type completes the scope of chemical explanation in the Group B curriculum. 

IV. Physical-Chemical Explanations of Long-Range Structure. 14... 

W. Visser et al. (Amsterdam Editions Rodopi, 1989) 171186 "Chemical Explanation and Physical Dynamics ... 

In the conclusion, the relationship of disciplines to schools and traditions is discussed, both in the particular instances of the Paris and London-Manchester schools and in the more general history of Continental and Anglo-American science, using elements of the disciplinary identity schema developed at the beginning of the book. I end with an inquiry into the views of mid-twentieth-century theoretical chemists and chemical physicists on the commensurability of their disciplines, the reducibility of chemical explanation to physical principles and laws, and the distinctiveness of chemistry from physics. 

We can safely say that chemical explanation from the late eighteenth century onward has been consistently characterized, like physics, by one or more of three kinds of theoretical approaches that are well known to analysts of scientific method (1) "realist," (2) "positive," and (3) "conventional." In this schema, realist theories can be characterized as hypotheticodeductive, with varying degrees of truth probability for their "picture" or "system" of the... 

Natural History and Chemical Explanation in the Nineteenth Century... 

On this occasion, Brodie clearly interchanged the roles in chemical explanation of the rational or constitutional formula and the molecular model, because the rest of his lecture is a critique of the formula. 

A third approach within the newly defined physical chemistry was to prove crucial to dealing with the old problems of affinity and reaction mechanisms. Like thermodynamics and radiation theory, it promised and eventually delivered a conceptual framework that constituted a truly theoretical chemistry. At the same time, this new ionic and electronic approach to chemical explanation served as an important testing ground for theoretical physicists primarily concerned with the physics tradition of ether- and electrodynamics. Helmholtz,... 

In its disciplinary development at the end of the nineteenth century, physical chemistry served as a bridge, not a wedge, between the mathematical abstractions of theoretical physics and the metaphorical descriptions of organic chemistry. Not only through novel theories but also through control of new instrumentation, much of it electrical and optical in nature, physical chemistry was to revitalize and transform techniques in the chemical laboratory and theories of chemical explanation. Notably for our concerns, speculations about reaction mechanisms in hydrocarbon chemistry were to begin to proliferate in the early 1900s. 

A few weeks before the first Solvay chemistry conference in 1922, French chemists signed a letter declining to reestablish relations among chemists of Western and Central Europe. A copy of this letter, 3 April 22, is in the Donnan Papers, UCL. On the Solvay conferences, see M. J. Nye, "Chemical Explanation and Physical Dynamics Two Research Schools at the First Solvay Chemistry Conference, 19221928," Annals of Science 46 (1989) 461480. 

For all his interest in combining physics and chemistry, Lowry was not much convinced in 1925, on the eve of the breakthroughs by Heitler and London, Hund, and Erich Hiickel, that the physicists most recent mechanics had benefited chemists. No doubt, Lowry told colleagues at the second Solvay chemistry conference, the physical chemist should learn to think in terms of quanta and energy levels, but the mineral chemist and the organic chemist had not yet gained much from these latest physical theories.35 In 1931, as we saw in chapter 6, Kirrmann still was of the opinion that the time had not yet arrived for the "mathematical stage" of chemical explanation. 

Chemical Explanation and Physical Dynamics Two Research Schools at the First Solvay Chemistry Conferences, 19221928." Annals of Science 46 (1989) 461480. 

A short chemical explanation is due for the species MLH and MLH1. MLH represents a complex formed between Cu2+, en and one proton. The notation does not indicate the structure of this species. However, there is little doubt that it would be a protonated ethylenediamine, which is coordinated by only one site, acting as a monodentate ligand. 

Many metal objects are vulnerable to damage from corrosion. A famous example is the Statue of Liberty. Research the history of the effects of corrosion on the Statue of Liberty. Give a chemical explanation for the processes involved. Describe the steps taken to solve the problem and the chemical reasons for these steps. 

MSN. 193.1. Prigogine, Chemical kinetics and dynamics, in Chemical Explanation—Characteristics, Development, Autonomy, Ann. New York Acad. Set 988, 128-132 (2003). 

Chemical Basis of Toxicity The toxicity of the peroxyacylnitrates to plants can be the result of several different processes. Any chemical explanation of the toxicity will have to explain the increasing toxicity of the series PAN, PPN, PBN, and PBzN. Three hypotheses have been tested the more toxic homologues are more readily taken up by the... 

The chemical explanation of alkaloid biogenesis is based on the consideration that all reactions are of a chemical nature and that the energy needed for life is produced by chemical reactions. Figure 73 shows a diagram of the chemical explanations for alkaloid biogenesis. From this diagram, it is clear that alkaloid... 

Figure 73. Chemical explanation for alkaloid biogenesis in organisms (c = catalysers).

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