Matter internal structure

We need insight to think like a chemist. Chemical insight means that, when we look at an everyday object or a sample of a chemical, we can imagine the atoms that make it up. Not only that, we need to be able to plunge, in our mind s eye, deep into the center of matter and imagine the internal structure of atoms. To visualize this structure and how it relates to the chemical properties of elements, we need to understand the electronic structure of an atom, the description of how its electrons are arranged around the nucleus. 

Minerals are the most abundant type of solid matter on the crust of the earth they are homogeneous materials that have a definite composition and an orderly internal structure. Minerals make up most of the bulk of rocks, the comminuted particles of sediments, and the greater part of most soils. Over 3000 minerals have been identified, and new ones are discovered each year. Only a few hundred, however, are common most of the others, such as, for example, the precious stones, are difficult to find (Ernst 1969). Table 3 lists common minerals and mineraloids. Many schemes have been devised for classifying the minerals. In the scheme presented in Table 4, minerals are arranged in classes according to their increasing compositional chemical complexity. 

Electron microscopy is a fairly straightforward technique to determine the size and shape of supported particles. It can also reveal information on the composition and internal structure of the particles, for example by detecting the characteristic X-rays that are produced by the interaction of the electrons with matter, or by analyzing how the electrons are diffracted [1,9],... 

Radiography was thus initiated without any precise understanding of the radiation used, because it was not until 1912 that the exact nature of x-rays was established. In that year the phenomenon of x-ray diffraction by crystals was discovered, and this discovery simultaneously proved the wave nature of x-rays and provided a new method for investigating the fine structure of matter. Although radiography is a very important tool in itself and has a wide field of applicability, it is ordinarily limited in the internal detail it can resolve, or disclose, to sizes of the order of 10 cm. Diffraction, on the other hand, can indirectly reveal details of internal structure of the order of 10 cm in size, and it is with this phenomenon, and its applications to metallurgical problems, that this book is concerned. The properties of x-rays and the internal structure of crystals are here described in the first two chapters as necessary preliminaries to the discussion of the diffraction of x-rays by crystals which follows. 

The physical relationships of various regions of the system and the transfer processes must also be defined. This will include a description of the important chemical reactions and their rate constants, dispersion and transport processes, and the fact that sediments and the oceans share a surface. The internal structure can be complex. For example, the population of kelp in a portion of the ocean can be coupled to the population of sea otters through the harvesting of kelp by the sea urchins and predation of sea urchins by sea otters. Exogenous inputs and outputs such as the influx of solar radiation and meteoritic matter and the efflux of infrared radiation, helium, and hydrogen are obvious examples when the system represents the entire Earth. 

A chemist s primary interest, as described in Chapter 1, is the behavior of matter, but to understand the behavior of matter, we must first understand its internal structure. What are the internal differences between the granite of Half Dome in Yosemite, the olive oil added to your pasta sauce, and the helium in a child s balloon A simple model of the structure of matter will help us begin to answer this question. 

Most people look at a gold nugget and see a shiny metallic substance that can be melted down and made into jewelry. A chemist looks at a substance such as gold and visualizes the internal structure responsible for those external characteristics. Now that we have discussed some of the general features of atoms and elements, we can return to the model of solid, liquid, and gas structures presented in Section 2.1 and continue in our quest to visualize the particle nature of matter. 

The empirical formula for cellulose is C0H10ObV however this does not tell anything about the internal structure of the molecule, With the recent discovery that cellulose, no matter what its Bource, has the same structural makeup, renewed interest has been given to cellulose chemistry. 

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