CHEMICAL AND PHYSICAL TRANSFORMATIONS OF MATTER

A principal goal of the chemical sciences is to understand and manipulate chemical and physical transformations of matter. We are using the term transfor- 

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Chapter 4 discusses chemical and physical transformations of matter, both those that occur naturally in the environment and in living organisms and those that are invented by chemical scientists. The study of transformations spans the range from efforts to gain a fundamental understanding of naturally occurring... 

THE CHEMICAL AND PHYSICAL TRANSFORMATION OF DETRITAL PARTICULATE ORGANIC MATTER... 

Pieces of coal are mixtures of materials somewhat randomly distributed in differing amounts. The mineral matter can be readily distinguished from the organic, which is itself a mixture. Coal properties reflect the individual constituents and the relative proportions. By analogy to geologic formations, the macerals are the constituents that correspond to minerals that make up individual rocks. For coals, macerals, which tend to be consistent in their properties, represent particular classes of plant parts that have been transformed into coal (40). Most detailed chemical and physical studies of coal have been made on macerals or samples rich in a particular maceral, because maceral separation is time consuming. 

The combustion is an extremely complex process including many chemical and physical phenomena of transformation of matter. The need and desire to know and control this process urges man to study its various aspects. Organic polymers are but one example of the multitude of materials used by man. They possess peculiar features and properties which individually affect the material behavior in a critical fire situation. It is, therefore, important to study the flammability characteristics of polymeric materials and the factors affecting them. 

The fundamental premise of chemistry is that all matter consists of molecules. The physical and chemical properties of matter are those of the constituent molecules, and the transformation of matter into different materials (compounds) is the result of their reactions to form new molecules. A molecule consists of two or more atoms held in a relatively fixed array via valence-electron orbital overlap (covalent bonds chemical bonds). 

Waste deposited in landfills undergoes biological, chemical and physical transformations that cause changes in solid, liquid (leachate) and gas phases. As much as 90% of the carbon that is released during the decomposition of organic matter in the waste migrates to landfill gas in the form of CH, COj and various hydrocarbons, whereas only 10% enters the leachate (Huber-Humer, 2007). The complex composition of the gas emitted from landfills and its uncontrolled emission into the atmosphere poses multiple threats and problems at different levels of coverage. 

Movement of raw and transformed materials can take place within the soil and results in zones of accumulation, depletion, or mixing. Formation, migration, and accumulation of different elements, clays, oxides, and organic matter can occur in different parts of the soil. These different zones or layers in soil that are approximately parallel to the surface are called soil horizons. Depleted or enriched soil horizons result in different depths in the soil having different chemical and physical properties. Translocations are caused by a combination of physical, chemical, and biological processes. 

Metal oxides have a significant role in influencing physical, chemical, and biological properties of soils. They may exist as ciystalline minerals, as short-range ordered (SRO) mineral colloids, or as surface coatings on clay minerals and organic matter. Organic compounds influence the formation, transformation, and surface properties of these metal oxides. The SRO A1... 

Many of the unsolved problems of physics and chemistry were concerned with combustion and detonation. A really well-developed scheme of normal combustion is seldom realized in nature. The most common form of gaseous combustion - turbulent combustion - was found to be the result of the hydrodynamic instability of the combustion process in a flow. Even in the simplest system, the physical scheme of turbulent combustion is very far from being perfectly understood. Just as in the analysis of detonative combustion, it is still possible to speak only of the universal instability of the hydrodynamic process accompanying the chemical transformation of matter. Actually, "turbulence is hardly the term for the result of the manifestation of this instability - the appearance of a multifront shockwave in the detonation front. However, the derivation of a complete physical scheme of detonation (especially in relation to condensed expls) will eventually follow from further research in this field... 

In earlier chapters, we investigated the nature of the solid, liquid, and gaseous states of matter in this chapter, we extend the discussion and look at transformations between these states. The discussion introduces the concept of equilibrium between different phases of a substance, and that concept will prove to be of the greatest importance when, in the following chapter, we turn to chemical transformations. The presence of solutes alters the physical properties of the solvent and gives rise to a number of important effects, including the flow of nutrients into and out of living cells. 

This review is organized as follows in Sec. 2, the large scale phenomenological physics of meteors is discussed, detailing observations as well as the respective current interpretations. Meteorites will not be discussed in this review. Studies of the chemical and physical processes associated with meteorites have been largely concerned with composition, phase transformations and entrapment of noble gases in the solid meteorites. The reader is referred to several reviews and textbooks on the subject.The elementary gas-phase molecular dynamics relevant to the meteor environment is discussed in Sec. 3, and will primarily focus on the hyperthermal nonequilibrium processes, in concert with the subject matter of this book. 

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