The Solid Crust

The surface has three interactive parts the solid crust, the aqueous components - oceans, seas, rivers, lakes - and the atmosphere. As stated, the thickness of these zones put together is only little more than 1-2% of the Earth s radius. The elements are in compounds in these layers, the environment,... 

Bromine.—J. H. L. Vogt-5 estimates that bromine occupies about the 25th place in the list of elements arranged in the relative order of their abundance and that the total crust of the earth has about O OOl per cent, of bromine—the solid portion O OOOOl per cent. The ratio of bromine to chlorine is about the same in sea water and in the solid crust, and amounts to 1 150. The ratio of chlorides to... 

Preparation of Lithium Nitride by Reacting Lithium with Nitrogen. Assemble an apparatus as shown in Fig. 83. Insert an iron tube into quartz tube 9. Using pincers, extract a small piece of metallic lithium from the kerosene in which it is stored (wear eye protection ), put it in a mortar, and carefully remove the solid crust covering the surface of the metal from all its sides with a thin knife. Lower the cleaned piece of lithium for two or three seconds into a beaker with methanol (why ) and put it into an iron boat. Put the latter into the iron tube. 

In compound form, fluorine is a fairly abundant element which constitutes approximately 0.1% of the solid crust of the earth. The chief fluorine-bearing minerals are fluorspar (CaF2), cryolite (Na3AlF6), and fluorapatite CaF2[Ca3(P04)2]3. ... 

It has seemed quite natural to think of silicon only in terms of the oxide, for practically all of the earth s silicon is bound up with oxygen. Together these two elements constitute some 76 per cent of the solid crust of the earth, and there is more than enough oxygen to combine with all the silicon. Free silicon therefore does not occur in nature, nor do its organic compounds. The only natural substance which has been demonstrated to have carbon-silicon bonds is the rare mineral moissanite, which is silicon carbide, and this ordinarily is not thought of as an organosilicon compound. 

Oxygen, silicon, and aluminum are the most abundant elements in the surface of the SILICATES earth (more than 80% of the atoms in the solid crust are oxygen or silicon, mostly in the form of silicates). The number of compounds and minerals that contain these elements is very large, and their importance in industrial uses matches their number. We can give only a very brief description of some of these compounds and will focus on a few of the silicates. 

The solid crust and the upper mantle make up the region called the lithosphere. Oxygen is the most abundant element in the lithosphere. Unlike the hydrosphere and the atmosphere, the lithosphere contains a large variety of other elements, including deposits of alkali, alkahne earth, and transition metal elements. Table 26-3 lists the most abundant elements in the continental crust portion of the hthosphere. With the exception of gold, platinum, and a few other rare metals that are found free in nature, most metallic elements occur as compounds in minerals. A mineral is a solid, inorganic compound found in nature. Minerals have distinct crystalhne structures and chemical compositions. Most are combinations of metals and nonmetals. 

Oxygen, for example, accounts for but a fraction of one per cent of the substance of the universe, yet it comprises 89 per cent of the weight of clouds and water and 46 per cent of the solid crust of the earth. 

Reviewing the roles of the various elements on earth, we find oxygen to be outstanding in many respects. It is by far the most abundant element in man himself as well as in the solid crust of the earth and in the oceans. It is the most important element in the atmosphere, and it is essential to man in hundreds of different forms. 

So constant and characteristic is the majestically slow decay of uranium that it can be used to measure the age of the earth. In 1907, the American chemist Bertram Borden Boltwood (1870-1927) suggested that the lead content of uranium minerals would serve as guide in this respect. If it is assumed that all the lead in the mineral originated from uranium decay, it would be easy to calculate how long a time must have elapsed to bring that amount of lead into existence. It was eventually calculated in this way that the solid crust of the earth must have been in existence for at least four billion years. 

If the air temperature exceeds the boiling point of the droplet solution, then a vapor will be formed. As the solid crust forms around each droplet, vapor pressure within the droplet is formed and the resultant effect of this pressure is dependent on the nature of the crust. A porous crust will release the vapor, but a nonporous crust may rupture resulting in fractured particles or fines from disintegrated particles. 

In both cases, the porosity of the solid crust is often evident in the characteristics of the falling rate period of the drying curve. If the film is highly nonporous, the rate will fall sharply and the evaporation time will be prolonged. However, if a highly... 

The collision that caused the moon remelted and mixed the rest of the Earth. Then the Earth and the moon cooled from the outside in. The solid crust, in contact with cold outer space, was rich in magnesium and iron, which balanced their positive charges with negative silicate. Magnesium in particular makes strong bonds and fits right into a silicate network with no space wasted (similar to how it fit with phosphates in Chapter 1), making the first rock in Earth s foundations out of four of the Big Six elements Mg, Si, O, and Fe. 

The oldest rocks on earth have been dated at 3.8 X lO y. The rocks at the earth s surface have been subjected to extensive weathering, so even older rocks may have existed. This age, 3.8 X lO y, thraefore represents the minimum possible age of the earth—the time since the solid crust first formed. Ages of meteorites, assumed to have solidified at the same time as other solid objects in the solar system, including earth, have been determined to be 4.4 X 10 y to 4.6 X 10 y. It is now believed from this and other evidence that the age of the earth is 4.6 X 10 y. 

If the interaction between solid SPH particles is as high as between liquid ones, the capillary effect is superimposed by the tendency of solid particles to narrow the pores. The net effect of capillarity is therefore much less pronounced and the formation of a solid crust sets in very early. In comparison to the simulation at 40° contact angle in Fig. 3.8, the solid crust grows into the direction, where the closest primary particle is located, whereas in the previous simulation the crust formation is rather an effect of the absence of liquid with more evenly distributed primary particles at the droplet s surface. In case of a low attraction between the solids, the results are very different. The solid particles do virtually not cluster at all, so that the final product after complete drying will probably be a densely packed, but not very stable agglomerate. 

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