Explanation in chemistry

By and large, a pejorative view of the methodological sophistication of chemical science has prevailed, notably, in comparison to physics. The structure of scientific explanation in chemistry often has been deemed child s play, or kitchen work. Chemistry frequently is characterized as a handmaiden, "like the maid occupied with daily civilization she is busy with fertilizers, medicines, glass, [and] insecticides. .. for which she dispenses the recipes."3 The Toulouse physicist Henri Bouasse enraged his colleague Paul Sabatier, who was awarded a Nobel Prize in chemistry in 1912, by jibing that chemists only aim to "faire la cuisine."4... 

Robert Boyle and Isaac Newton wanted to explain the properties of substances in terms of the properties of constituent corpuscles, which might be complex aggregates or else simple atoms. There was no contradiction between this approach and the alchemical ideas that they built into their chemical practice. But although they both advocated mechanical explanations in chemistry, they meant different things by mechanical. 

Explanation in chemistry displays a few characteristics worth noting, as follow. 

These distinctive features of explanation in chemistry might be useful for understanding the essential goals of the discipline. They also provide further evidence that... 

Zielonacka-Lis. E. 1998. "Some Remarks on the Specificity of Scientific Explanation in Chemistry." Presentation at the Second International Society for the Philosophy of Chemistry, 3-7 August 1998, Sidney Sussex College, U. K. 

Johannes Hunger (Chapter 7) takes on another of the standard topics in the philosophy of science, explanation. Hunger examines, in detail, various ways that chemists explain and predict the structural properties of molecules. We learn about ab initio methods, empirical force field models and neural network models, each of which have been used to explain and predict molecular structure. And we learn that none of these approaches can be subsumed under either hypothetico-deductive or causal models of explanation. Either chemistry does not offer proper explanations (the normative option) or our philosophical models for explanation are inadequate to cover explanation in chemistry (the descriptive option). Hunger takes the descriptive option and sketches a more pragmatic approach to the explanation that develops Bas van Fraassen s approach to explanation for chemistry. Once again, we find that the philosophy of science has much to learn from the philosophy of chemistry. 

Add and base behaviour can be explained using different theories. How are the explanations in chemistry different from explanations in other subjects such as history ... 

Almost every argument and explanation in chemistry boils down to a consideration of some aspect of a single property the energy. Energy determines what molecules can form, what reactions can occur, how fast they can occur, and (with a refinement in our conception of energy) in which direction a reaction has a tendency to occur. 

Still on the periodic table, the second paper examines attempts to explain the periodic system through electronic configurations of atoms. The decision to place this article in the present section is based on the fact that the question of reduction is being restricted to asking about the status of the periodic system rather than chemistry as a whole as in the case of the papers in section A. The article in question also provides an opportunity to consider different levels of explanation in chemistry. From a methodological point of view it involves an examination of the major kinds of approaches in computational quantum chemistry, namely the wavefunction and density functional approaches respectively. 

Eilks, L, Witteck, T., Pietzner, V. (2012). The role and potential dangers of visualisation when learning about submicroscopic explanations in chemistry education. Centre for Educational Policy Studies Journal, 2, 125-145. 

The meaning of logical cormectives (e.g., thus, because, however ) is vital in the conduct of explanation in chemistry, but may not be understood (Gardner, 1975). This potential problem should not be overlooked in the design of informal resources. 

These ideas, developed for an electrochemical cell, have great importance in chemistry because they are also applicable to chemical reactions that occur in a single beaker. Without an electric circuit or an opportunity for electric current to flow, the chemical changes that occur in a cell can be duplicated in a single solution. It is reasonable to apply the same explanation. 

There have been a number of attempts to meet the "Lowdin challenge," as it has been called. Allen and Knight published an explanation in the International Journal of Quantum Chemistry, which has turned out to be rather problematic as I have recently argued [25-27], In addition, Ostrovsky has published an account in which he claims to explain the n + ( rule, but this account is far from transparent, or convincing, at least to this author [28],... 

Oversby, J. (2000). Models in explanations of chemistry The case of acidity. In J. K. Gilbert C. J. Boulter (Eds.), Developing models in. science education. Dordrecht/Boston/London Kluwer academic publishers. 

This study suggests that much more research is needed into aspects of metacog-nitive capability and into the use of the Model of Modelling if we are to provide fuller explanations of the processes involved in understanding the three levels of representation in chemistry . For example ... 

Basically, three reactions were evoked to support the occurrence of 5a-C-centered radicals 10 in tocopherol chemistry. The first one is the formation of 5a-substituted derivatives (8) in the reaction of a-tocopherol (1) with radicals and radical initiators. The most prominent example here is the reaction of 1 with dibenzoyl peroxide leading to 5a-a-tocopheryl benzoate (11) in fair yields,12 so that a typical radical recombination mechanism was postulated (Fig. 6.6). Similarly, low yields of 5a-alkoxy-a-tocopherols were obtained by oxidation of a-tocopherol with tert-butyl hydroperoxide or other peroxides in inert solvents containing various alcohols,23 24 although the involvement of 5 a-C-centered radicals in the formation mechanism was not evoked for explanation in these cases. 

FIG. 2.1. The Periodic Table of the elements, the full understanding of which provides ideally a reductionist approach to the explanation of chemistry. The essential bulk and trace elements for living cells are also shown but knowledge of them is not in any way adequate for an explanation of biology... 

A very brief introduction to the important topic of bioinorganic electron transfer mechanisms has been included in Section 1.8 (Electron Transfer) of Chapter 1. Discussions of Marcus theory for protein-protein electron transfer and electron or nuclear tunneling are included in the texts mentioned in Chapter 1 (references 3-7). A definitive explanation of the underlying theory is found in the article entitled Electron-Transfer in Chemistry and Biology, written by R. A. Marcus and N. Sutin and published in Biochem. Biophys. Acta, 1985, 811, 265-322. 

The question whether atoms exist or not.. . belongs rather to metaphysics. In chemistry we have only to decide whether the assumption of atoms is an hypothesis adapted to the explanation of chemical phenomena. . . [and] whether a further development of the atomic hypothesis promises to advance our knowledge of the mechanisms of chemical phenomena.. .. I rather expect that we shall some day find, for what we now call atoms, a mathematico-mechanical explanation, which will render an account of atomic weight, of atomicity, and of numerous other properties of the so-called atoms. 50... 

More radically, it can be argued that chemists recognized before most physicists the conventional character of the basic definitions and premises of scientific explanation systems, an argument usually identified in physics with Heinrich Hertz, Henri Poincare, and Edouard LeRoy at the end of the nineteenth century. And finally, chemists recognized early on that multiple explanations are superior to a simple but wrong explanation. In short, chemistry had a principle of complementarity long before physics did. 

Some substances will dissolve in a particular solvent and others will not. There is a general rule in chemistry that states that like dissolves like. This general statement may serve as an answer in the multiple-choice questions, but does not serve as an explanation in the free-response questions. This simply means that polar substances (salts, alcohols, etc.) will dissolve in polar solvents such as water, and nonpolar solutes, such as iodine, will dissolve in nonpolar solvents such as carbon tetrachloride. The solubility of a particular solute is normally expressed in terms of grams solute per 100 ml. of solvent (g/mL) at a specified temperature. The temperature must be specified because the solubility of a particular substance will vary with the temperature Normally, the solubility of solids dissolving in liquids increases with increasing temperature, while the reverse is true for gases dissolving in liquids. 

Interviewees provided several explanations for choosing chemistry as a major. One interviewee explained When I entered college, students told me not to major in chemistry because it was hard. I think we [interviewee and friends] did it (majored in chemistry) because it sounded like a challenge. One remarked It seemed like it was a powerful discipline to me. You could make, discover and invent new things. ... 

These calculations are so basic to the field that you should go back and carefully review the two examples in this section the calculation of weight percents in N2O and the inference of the formula for aluminum oxide. Then you can practice stoichiometric calculations on the following pair of problems, which are answered and explained in Appendix A. Many such practice exercises are included in this book so you can determine whether you understand the major concepts of chemistry. It is well worth your time to study these examples and their explanations in Appendix A until you can do the calculations correctly. 

Group theory has been useful in chemistry in several ways. First, it has provided simple, qualitahve explanations for the behavior of matter. For example, why can the states of electrons in any atom be classified, to a good approximation, by the four quantum numbers n, I, rrii and m Why, in their ground states, is BeH2 a linear molecule but H2O bent Why do certain transitions not appear in an absorption spectrum Lengthy computations can provide correct but uninformative answers to these questions group theory can provide perspicuous explanations of the factors that determine these answers. 

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