The Element Carbon

Some methane is manufactured hv the distillation of coal. Coal is a combustible nick formed from the remains of decayed vegetation. Ii is ihe only rock containing significant amounls of carbon. The elemental composition of coal varies between 60% and 95% carbon. Coal also contains hydrogen and oxygen, with small concentrations of nitrogen, chlorine, sulfur, and several metals. Coals are classified by the amount of volatile material they contain, that is. by how much of Ihe mass is vaporized when the coal is healed to about 900 C in the absence of air. Coal that contains more than 15% volatile material is called bituminous coal. Substances released from bituminous coal when it is distilled, in addition to methane, include water, carbon dioxide, ammonia, benzene, toluene, naphthalene, and anthracene In addition, the distillation also yields oils, tars, and sulfur-containing products. The non-volatile component of coal, which remains after distillation, is coke. Coke is almost pure carbon and is an excellent fuel, However, it may contain metals, such as arsenic and lead, which can he serious pollutants if ihe combustion products are released into the atmosphere. 

Carbon, the element with symbol C, gets its name from the Latin word carbo Carbo in Latin, means a black rock that can burn The word highlights a physical property (its... 

In most publications, including Chemical Abstracts and Beilstein, molecular formulae are given in Hill system order. For organic compounds, the order is C first, then H, and then the remaining element symbols alphabetically. For compounds that do not contain carbon, the element symbols are ordered alphabetically (see Hill, E. A., J. Am. Chem. Soc., 22, 478-490, 1900). 

As shown in Fig. 2, in CSIA, organic compounds are separated with gas chromatography and on-line fed to a combustion imit where they are totally converted to simple gases such as CO2 or H2 (for isotope analysis of carbon and hydrogen, respectively). The combustion gases are transferred to an isotope-ratio mass spectrometer (IRMS) that measures precisely the isotopic composition of these gases. For example, in the case of carbon, the element by far most frequently determined today, the ratio of masses 44 ( C02) and 45 ( C02) is measured. 

The physically-adsorbed gases and vapors can be recovered from the carbon surface by evacuation or by passing an inert gas over the surface of the carbon the elemental sulfur can be removed by extraction with various solvents. The chenusorbed sulfur that is present in the form of very stable carbon-sulfur surface compounds is difficult to recover. It cannot be removed by extraction or by heat treatment alone. It can, however, be conveniently removed by heat treatment in hydrogen gas at 500°C. The formation and properties of carbon-sulfur surface compounds formed on carbons as a result of treatment with sulfur dioxide, hydrogen sulfide, or carbon disulfide is beyond the scope of this book, but they have been dealt with in great detail in our earlier books. Active Carbon and Carbon BlackP... 

Schell and Bames (1986) and Arakel and Hongjun (1992) described the modes of lead transport in aquatic systems. The predominant forms of lead that are bioactive in aquatic systems are lead oxide and lead carbonate, the element being adsorbed and transportable in colloidal species of clay minerals, Fe—Mn oxides and hydroxides, and suspended organic compounds such as humates and fiilvates. Other transportable forms are soluble chelates and ions, or as particulates. 

Simply stated, inorganic chemistry deals with the 117 elements in the periodic table other than carbon. The elements in the periodic table are broadly grouped into three classifications metals, nonmetals, and metalloids (or semimetals). Inorganic chemists describe the physical and chemical properties of the elements themselves, as well as all of the chemical compounds the elements can form, both in nature and in the laboratory. 

In photosynthesis the CO2 of the air and H2O are converted into carbohydrates. Carbohydrates are compounds which contain, in addition to carbon, the elements hydrogen and oxygen in the same ratio as that in which they occur in water. Thus, the simplest carbohydrate has the formula CH2O, as is shown by the equation ... 

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