Classifying According to Chemical Composition

Hormones can be classified according to chemical composition, solubility properties, location of receptors, and the namre of the signal used to mediate hormonal action within the cell. A classification based on the last two properties is illustrated in Table 42-3, and general feamres of each group are illustrated in Table 42-. ... 

Silica Brick. Under ASTM C416, types A and B silica bricks are classified according to chemical composition and strength. Silica brick must have an average modulus of rupture of 3.5 MPa (500 psi), <1.5% A O no more than 0.2% Ti02, <2.50% Fe203, and <4.00% CaO. Type A brick must have a flux factor <0.5. The flux factor is equal to the percent alumina plus twice the percent of alkalies. Type B are all other silica brick covered by the standard chemical and strength specifications. 

Solvents have been classified on various arbitrary bases (1) boiling point, (2) evaporation rate, (3) polarity, (4) industrial applications, (5) chemical composition, (6) proton donor and proton acceptor relationships, and (7) behavior toward a dye, Magdala Red, Thus on the basis of industrial application one can classify solvents as those for (1) acctyl-ccliulosc, (2) pyroxylin, 13) resins and lubber, (4) cellulose ether, (5) chlorinated rubber, (6) synthetic resins, and (7) solvents and blending agents for cellulose ester lacquers. Solvents classified according to chemical composition are noted below. 

Virtually every element in the periodic table is found in the atmosphere however, when classifying atmospheric species according to chemical composition, it proves to be convenient to use a small number of major groupings such as... 

It comes as no surprise that chemists classified materials differently in different practical and commercial contexts. CXu analyses in parts II and III, however, will not focus on these types of differences. Rather, we are mainly concerned with taxonomic diversity in contexts of conceptual or philosophical inquiry, and we will show that even in contexts of predominantly conceptual concerns chemists classified substances in different ways. The most important classificatory difference in the context of conceptual inquiry was classification according to chemical composition versus classification according to perceptible properties and provenance. Qassification of substances according to chemical composition was restricted to a comparatively small range of substances, which were then mapped by chemical tables. The classi-... 

In the new system minerals were classified according to their composition, determined by chemical analysis. He summarized his new views in a book 1758, which in 1770 was translated into Enghsh with the title Attempt at Mineralogy or the Arrangement of the Mineral Sphere. 

Plastics and resins can be classified in several different ways. They can be grouped according to chemical composition (polyolefin, poly acrylate) according to physical characteristics (elastomeric, thermoplastic, thermoset) according to form (sheet, film, fiber) and according to function (packaging film, structural adhesive, engineering thermoplastic). 

Examination of the chemical composition of cells reveals a dazzling variety of organic compounds covering a wide range of molecular dimensions (Table 1.2). As this complexity is sorted out and biomolecules are classified according to the similarities in size and chemical properties, an organizational pat-... 

The chemical composition of wood fuels on dry basis can be simplified by the average empirical formula CH1.4O0.7 [66], The major components of wood fuels can be classified according to Figure 50. 

Solid-state systems are frequently classified according to their physical, structural or chemical properties. Such schemes are extremely helpful since properties related to any such classification are typically known and facilitate identifying solids with special material classes. The best-known examples of these schemes are conductivity or resistivity measurements by means of which metals are easily distinguishable from insulators. However, frequently clear-cut decisions between material classes are not possible, since anisotropy, chemical composition, binding forces and local effects wash out distinct properties and lead to competition or coexistence. 

Organic solvents are usually classified according to their chemical composition. The aliphatic hydrocarbons, which are straight or branched chains saturated with hydrogen, act primarily as depressants to the central nervous system, but otherwise they are generally as inert biochemically as they are chemically. 

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