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Carbon Disulfide
Carbon disulfide (also spelled as carbon disulphide) is a neurotoxic, colorless, volatile liquid with the formula and structure . The compound is used frequently as a building block in organic chemistry as well as an industrial and chemical non-polar solvent. It has an "ether-like" odor, but commercial samples are typically contaminated with foul-smelling impurities.. It is of comparable toxicity to carbon monoxide. History In 1796, the German chemist Wilhelm August Lampadius (1772–1842) first prepared carbon disulfide by heating pyrite with moist charcoal. He called it "liquid sulfur" (''flüssig Schwefel''). The composition of carbon disulfide was finally determined in 1813 by the team of the Swedish chemist Jöns Jacob Berzelius (1779–1848) and the Swiss-British chemist Alexander Marcet (1770–1822). Their analysis was consistent with an empirical formula of CS2. Occurrence, manufacture, properties Small amounts of carbon disulfide are released by volcanic eruptio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chloroform
Chloroform, or trichloromethane, is an organic compound with chemical formula, formula Carbon, CHydrogen, HChlorine, Cl3 and a common organic solvent. It is a colorless, strong-smelling, dense liquid produced on a large scale as a precursor to PTFE. It is also a precursor to various refrigerants. It is trihalomethane. It is a powerful anesthetic, euphoriant, anxiolytic, and sedative when inhaled or ingested. Structure The molecule adopts a tetrahedral molecular geometry with C3v symmetry group, symmetry. Natural occurrence The total global flux of chloroform through the environment is approximately tonnes per year, and about 90% of emissions are natural in origin. Many kinds of seaweed produce chloroform, and fungi are believed to produce chloroform in soil. Abiotic processes are also believed to contribute to natural chloroform productions in soils although the mechanism is still unclear. Chloroform volatilizes readily from soil and surface water and undergoes degradation in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Solvent
A solvent (s) (from the Latin '' solvō'', "loosen, untie, solve") is a substance that dissolves a solute, resulting in a solution. A solvent is usually a liquid but can also be a solid, a gas, or a supercritical fluid. Water is a solvent for polar molecules and the most common solvent used by living things; all the ions and proteins in a cell are dissolved in water within the cell. The quantity of solute that can dissolve in a specific volume of solvent varies with temperature. Major uses of solvents are in paints, paint removers, inks, and dry cleaning. Specific uses for organic solvents are in dry cleaning (e.g. tetrachloroethylene); as paint thinners (toluene, turpentine); as nail polish removers and solvents of glue (acetone, methyl acetate, ethyl acetate); in spot removers (hexane, petrol ether); in detergents ( citrus terpenes); and in perfumes (ethanol). Solvents find various applications in chemical, pharmaceutical, oil, and gas industries, including in chemical syn ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Silica Gel
Silica gel is an amorphous and porous form of silicon dioxide (silica), consisting of an irregular tridimensional framework of alternating silicon and oxygen atoms with nanometer-scale voids and pores. The voids may contain water or some other liquids, or may be filled by gas or vacuum. In the last case, the material is properly called silica xerogel. Silica xerogel with an average pore size of 2.4 nanometers has a strong affinity for water molecules and is widely used as a desiccant. It is hard and translucent, but considerably softer than massive silica glass or quartz; and remains hard when saturated with water. Silica xerogel is usually commercialized as coarse granules or beads, a few millimeters in diameter. Some grains may contain small amounts of indicator substance that changes color when they have absorbed some water. Small paper envelopes containing silica xerogel pellets, usually with a "do not eat" warning, are often included in dry food packages to absorb any h ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Natural Gas
Natural gas (also called fossil gas or simply gas) is a naturally occurring mixture of gaseous hydrocarbons consisting primarily of methane in addition to various smaller amounts of other higher alkanes. Low levels of trace gases like carbon dioxide, nitrogen, hydrogen sulfide, and helium are also usually present. Natural gas is colorless and odorless, so odorizers such as mercaptan (which smells like sulfur or rotten eggs) are commonly added to natural gas supplies for safety so that leaks can be readily detected. Natural gas is a fossil fuel and non-renewable resource that is formed when layers of organic matter (primarily marine microorganisms) decompose under anaerobic conditions and are subjected to intense heat and pressure underground over millions of years. The energy that the decayed organisms originally obtained from the sun via photosynthesis is stored as chemical energy within the molecules of methane and other hydrocarbons. Natural gas can be burned fo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sulfur
Sulfur (or sulphur in British English) is a chemical element with the symbol S and atomic number 16. It is abundant, multivalent and nonmetallic. Under normal conditions, sulfur atoms form cyclic octatomic molecules with a chemical formula S8. Elemental sulfur is a bright yellow, crystalline solid at room temperature. Sulfur is the tenth most abundant element by mass in the universe and the fifth most on Earth. Though sometimes found in pure, native form, sulfur on Earth usually occurs as sulfide and sulfate minerals. Being abundant in native form, sulfur was known in ancient times, being mentioned for its uses in ancient India, ancient Greece, China, and ancient Egypt. Historically and in literature sulfur is also called brimstone, which means "burning stone". Today, almost all elemental sulfur is produced as a byproduct of removing sulfur-containing contaminants from natural gas and petroleum.. Downloahere The greatest commercial use of the element is the production o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Coke (fuel)
Coke is a grey, hard, and porous coal-based fuel with a high carbon content and few impurities, made by heating coal or oil in the absence of air—a destructive distillation process. It is an important industrial product, used mainly in iron ore smelting, but also as a fuel in stoves and forges when air pollution is a concern. The unqualified term "coke" usually refers to the product derived from low-ash and low-sulphur bituminous coal by a process called coking. A similar product called petroleum coke, or pet coke, is obtained from crude oil in oil refineries. Coke may also be formed naturally by geologic processes.B. Kwiecińska and H. I. Petersen (2004): "Graphite, semi-graphite, natural coke, and natural char classification — ICCP system". ''International Journal of Coal Geology'', volume 57, issue 2, pages 99-116. History China Historical sources dating to the 4th century describe the production of coke in ancient China. The Chinese first used coke for heating ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carbon
Carbon () is a chemical element with the symbol C and atomic number 6. It is nonmetallic and tetravalent In chemistry, the valence (US spelling) or valency (British spelling) of an element is the measure of its combining capacity with other atoms when it forms chemical compounds or molecules. Description The combining capacity, or affinity of an ...—its atom making four electrons available to form covalent bond, covalent chemical bonds. It belongs to group 14 of the periodic table. Carbon makes up only about 0.025 percent of Earth's crust. Three Isotopes of carbon, isotopes occur naturally, Carbon-12, C and Carbon-13, C being stable, while Carbon-14, C is a radionuclide, decaying with a half-life of about 5,730 years. Carbon is one of the Timeline of chemical element discoveries#Ancient discoveries, few elements known since antiquity. Carbon is the 15th Abundance of elements in Earth's crust, most abundant element in the Earth's crust, and the Abundance of the c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Marsh
A marsh is a wetland that is dominated by herbaceous rather than woody plant species.Keddy, P.A. 2010. Wetland Ecology: Principles and Conservation (2nd edition). Cambridge University Press, Cambridge, UK. 497 p Marshes can often be found at the edges of lakes and streams, where they form a transition between the aquatic and terrestrial ecosystems. They are often dominated by grasses, rushes or reeds. If woody plants are present they tend to be low-growing shrubs, and the marsh is sometimes called a carr. This form of vegetation is what differentiates marshes from other types of wetland such as swamps, which are dominated by trees, and mires, which are wetlands that have accumulated deposits of acidic peat. Marshes provide habitats for many kinds of invertebrates, fish, amphibians, waterfowl and aquatic mammals. This biological productivity means that marshes contain 0.1% of global sequestered terrestrial carbon. Moreover, they have an outsized influence on climate resi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Volcano
A volcano is a rupture in the crust of a planetary-mass object, such as Earth, that allows hot lava, volcanic ash, and gases to escape from a magma chamber below the surface. On Earth, volcanoes are most often found where tectonic plates are diverging or converging, and most are found underwater. For example, a mid-ocean ridge, such as the Mid-Atlantic Ridge, has volcanoes caused by divergent tectonic plates whereas the Pacific Ring of Fire has volcanoes caused by convergent tectonic plates. Volcanoes can also form where there is stretching and thinning of the crust's plates, such as in the East African Rift and the Wells Gray-Clearwater volcanic field and Rio Grande rift in North America. Volcanism away from plate boundaries has been postulated to arise from upwelling diapirs from the core–mantle boundary, deep in the Earth. This results in hotspot volcanism, of which the Hawaiian hotspot is an example. Volcanoes are usually not created where two tectonic plates slide ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Empirical Formula
In chemistry, the empirical formula of a chemical compound is the simplest whole number ratio of atoms present in a compound. A simple example of this concept is that the empirical formula of sulfur monoxide, or SO, would simply be SO, as is the empirical formula of disulfur dioxide, S2O2. Thus, sulfur monoxide and disulfur dioxide, both compounds of sulfur and oxygen, have the same empirical formula. However, their molecular formulas, which express the number of atoms in each molecule of a chemical compound, are not the same. An empirical formula makes no mention of the arrangement or number of atoms. It is standard for many ionic compounds, like calcium chloride (CaCl2), and for macromolecules, such as silicon dioxide (SiO2). The molecular formula, on the other hand, shows the number of each type of atom in a molecule. The structural formula shows the arrangement of the molecule. It is also possible for different types of compounds to have equal empirical formulas. Sampl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alexander Marcet
Alexander John Gaspard Marcet FRS (1 August 1770 – 19 October 1822), was a Genevan-born physician who became a British citizen in 1800. His wife Jane Marcet was a prolific author, whose series of books entitled 'Conversations' treated topics such as chemistry, botany, religion and economics. Biography Marcet was born at Geneva, and received his school education there. In 1794 he went to the University of Edinburgh, where he graduated with an MD on 24 June 1797. He wrote a thesis on diabetes, printed at Edinburgh in the same year. He then took a house in London, worked as assistant physician at Cary Street Dispensary, and was admitted a licentiate of the Royal College of Physicians on 25 June 1799. He then became a physician at Finsbury Dispensary, and at Guy's Hospital on 18 April 1804. He lectured there on chemistry between 1805 and 1819. Marcet took charge of the temporary military hospital at Portsmouth in 1809 for some months, when it contained invalids from Walcheren. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Jöns Jacob Berzelius
Baron Jöns Jacob Berzelius (; by himself and his contemporaries named only Jacob Berzelius, 20 August 1779 – 7 August 1848) was a Swedish chemist. Berzelius is considered, along with Robert Boyle, John Dalton, and Antoine Lavoisier, to be one of the founders of modern chemistry. Berzelius became a member of the Royal Swedish Academy of Sciences in 1808 and served from 1818 as its principal functionary. He is known in Sweden as the "Father of Swedish Chemistry". Berzelius Day is celebrated on 20 August in honour of him. Although Berzelius began his career as a physician, his enduring contributions were in the fields of electrochemistry, chemical bonding and stoichiometry. In particular, he is noted for his determination of atomic weights and his experiments that led to a more complete understanding of the principles of stoichiometry, which is the branch of chemistry pertaining to the quantitative relationships between elements in chemical compounds and chemical reactions and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
