Basic Chemical Principles

The tendency of the halogens to form chain-like polyanions that are stabilized by delocalization of the negative charge [15,34] is a basic chemical principle. Donor-acceptor interactions between Lewis-acidic Br2 and halide anions, but also with polyhalides acting as Lewis bases, give rise to the formation of a variety of homo and heteroatomic adducts. The maximum number of atoms in these chains increases with the atomic weights... 

Although poly(vinyl chloride) (PVC) is one of the most important commercial polymers, its outdoor use has been restricted by its photochemical instability. The reasons for this instability are incompletely understood, but some progress has been made recently on this problem, and the present paper attempts to summarize the current status of fundamental knowledge in this field. This survey is not intended to be comprehensive it is concerned primarily with work published since the early 1970 s and with basic chemical principles rather than technological developments. The photodegradation of PVC has been discussed in other recent reviews (1,2, 3 4) ... 

Whether for a dramatic scene or a science-fiction fantasy, the use of artificial fog to create ambience and special effects is commonplace in theatrical and film productions. On what basic chemical principles do fog machines operate ... 

Eddowes M.J., Direct immunochemical sensing basic chemical principles and fundamental limitations, Biosens 1987 3 1-15. 

This equation can be said to represent the condition of complete saturation of all predetermined (in relation to the periodic system) anionic and cationic valences. There are, however, numerous examples of compounds whose predetermined classic valences do not satisfy Eqn. II.4. Although these inconsistencies could, in principle, have been cured in several ways, chemists have traditionally got round the problem by maintaining the anionic valences, and leaving the adjustable cationic valences to be determined from Eqn. II.4 or equivalents thereof. It follows that Eqn. II.4 can no longer be seen as an expression having general significance for required saturation of all valences, since it now merely expresses the already invoked saturation of anionic valences. There are many cases where it is not even sufficient to manipulate the cationic valences. Therefore, the apparent symmetry of Eqn. II.4 does not represent a basic chemical principle. 

Summary This chapter on basic chemical principles should serve as a review if you have had a pre-AP chemistry course in school. We assume (and we all know about assumptions) that you know about such things as the scientific method, elements, compounds, and mixtures. We may mention elementary chemistry topics like this, but we will not spend a lot of time discussing them. When you are using this book, have your textbook handy. If we mention a topic and it doesn t sound familiar, go to your textbook and review it in depth. We will be covering topics that are on the AP exam. There is a lot of good information in your text that is not covered on the AP exam, so if you want more, read your text. 

To gain an understanding of how these beautiful effects are produced, we will begin with a review of some basic chemical principles and then proceed to discuss various pyrotechnic systems. 

Chemistry and the Environment is designed to intentionally motivate and engage students by connecting basic chemical principles and civic engagement through public issues such as air quality, ozone depletion,... 

For readers requiring knowledge of basic chemical principles R.M. Harrison and S.J. de Mora, Introductory Chemistry for the Environmental Sciences, 2nd edn, Cambridge University Press, Cambridge, 1996. 

The substantial changes include more emphasis on organic chemistry, soils, contaminants in continental water and remediation of contaminated land. T> do this effectively, the terrestrial environments chapter from the first edition has been split into two chapters dealing broadly with solids and water. We have reorganized the box structure of the book and have placed some of the original box material, augmented by new sections, to form a new chapter outlining some of the basic chemical principles that underpin most sections of the book. 

The importance of pH as a master variable controlling chemical reactions in soils has been stressed in previous chapters. However, soils subjected to fluctuations in water content come under the influence of another master variable the reduction-oxidation (or redox) potential Under conditions of water saturation, the lack of molecular oxygen can result in a sequence of redox reactions that changes the soil pH. In this sense the redox state of the soil exerts control over the pH. The nature of redox reactions will be discussed in this chapter, as these reactions profoundly influence metal ion solubility and the chemical form of ions and molecules dissolved in soil solution. The reader is referred to section 1.2f in Chapter 1 for a review of the basic chemical principles necessary for the understanding of redox reactions. 

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