Quicklime or Calcium Oxide

Inorganic compound, white or grayish white solid, chemical formula CaO, made by roasting limestone (calcium carbonate, CaCO3) until all the carbon dioxide (CO2) is driven off. One of the four most important basic chemical commodities, it is used as a refractory, as a flux in steel manufacture, as a CO2 absorbent, to remove contaminants from stack gases, to neutralize various acids, in pulp and paper, in insecticides and fungicides, in sewage treatment, and in the manufacture of glass, calcium carbide, and sodium carbonate. Adding water to lime yields calcium hydroxide (slaked lime, calcium hydrate, hydrated lime, or caustic lime), which is used in mortar, plasters, cements, whitewash, hide dehairing, and water softening and purification and as a source of other calcium salts.

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calcium oxide

calcium oxide, chemical compound, CaO, a colorless, cubic crystalline or white amorphous substance. It is also called lime, quicklime, or caustic lime, but commercial lime often contains impurities, e.g., silica, iron, alumina, and magnesia. It is prepared by heating calcium carbonate calcium carbonate, CaCO3, white chemical compound that is the most common nonsiliceous mineral. It occurs in two crystal forms: calcite, which is hexagonal, and aragonite, which is rhombohedral.. (e.g., limestone limestone, sedimentary rock wholly or in large part composed of calcium carbonate. It is ordinarily white but may be colored by impurities, iron oxide making it brown, yellow, or red and carbon making it blue, black, or gray. The texture varies from coarse to fine.in a special lime kiln to about 500°C; to 600°C;, decomposing it into the oxide and carbon dioxide. Calcium oxide is widely used in industry, e.g., in making porcelain and glass; in purifying sugar; in preparing bleaching powder bleaching powder, white or nearly white powder that is usually a mixture of calcium chloride hypochlorite, CaCl(OCl); calcium hypochlorite, Ca(OCl)2; and calcium chloride, CaCl2. , calcium carbide, and calcium cyanamide; in water softeners; and in mortars and cements. In agriculture it is used for treating acidic soils (liming liming (lim`ing), application to the soil of calcium in various forms, generally as ground limestone, but also as marl, chalk, . It is incandescent when heated to high temperatures; the Drummond light, or limelight, provides a brilliant white light by heating a cylinder of lime with the flame of an oxyhydrogen torch. Calcium oxide is a basic anhydride, reacting with water to form calcium hydroxide calcium hydroxide, Ca(OH)2, colorless crystal or white powder. It is prepared by reacting calcium oxide (lime) with water, a process called slaking, and is also known as hydrated lime or slaked lime. the link for more information. ; during the reaction (slaking) much heat is given off and the solid nearly doubles its volume.

Limestone

Limestone is a "chemical" sedimentary rock that is composed mostly of calcite (CaCO3) that precipitates from seawater. Limestone, the most common chemical sedimentary rock in Texas, is commonly white to gray. Because the dominant mineral is calcite, limestone reacts with a strong effervescence when tested using a dilute acid such as hydrochloric acid or vinegar. Groundwater is slightly acidic and, hence, slowly dissolves limestone. This process has produced the caves of Texas.

Variations of limestone include marl, a muddy limestone, and chalk, a limestone composed of microscopic calcareous algae and tiny shells of marine organisms. Limestone is common in the Hill Country and the Trans-Pecos of Texas. Limestone in Texas is quarried for cement, aggregate, and building stone. High-calcium-content limestone is used in water purification and sewage treatment.

The limestone sample in the Texas Rock Kit was collected in Travis County and is Cretaceous in age.