Oxide CaO

Some carbonates are important industrial chemicals. Calcium carbonate occurs naturally in several forms, including limestone, and is used in the production of quicklime, calcium oxide CaO, slaked (or hydrated) lime, calcium hydroxide Ca(OH)2 and cement. 

After drying over quicklime, calcium oxide CaO, the ammonia is collected by upward delivery. (N.B. Both of the common drying agents, calcium chloride and concentrated sulphuric acid, combine with the gas.)... 

Portland Cement. Portland cement is obtained by calcining a mixture of substances to produce an appropriate ratio of the oxides CaO, MgO, AI2O2, Fe202, and Si02 (9) (see Cement). 

The chemical formula for limestone is CaCOj and upon burning forms calcium oxide (CaO), which is known as burnt lime. Calcium oxide, when mixed with water, forms calcium hydroxide (Ca(OH)2). Calcium hydroxide is used to treat water as a coagulation aid along with aluminum sulfate. 

I German degree. = i part calcium oxide (CaO) per 100,000 parts of water... 

Determination of oxalate as calcium oxalate and as calcium carbonate or calcium oxide Discussion. The neutral solution of alkali oxalate is acidified with acetic (ethanoic) acid, heated to boiling, and precipitated with boiling calcium chloride solution. After standing for 12 hours, the precipitate is filtered off, washed with hot water, and weighed either as calcium oxalate, or after heating, as calcium carbonate, CaC03, or as calcium oxide, CaO. Further details are given in Section 11.22. 

If a limestone or dolomite sorbant is added to the hot sand bed, the calcium oxide (CaO) produced reacts and combines with S02, thus reducing the emission of the pollutant. 

Calcium carbonate decomposes to calcium oxide, CaO, or quicklime, when heated ... 

Three other compounds of s-block elements—calcium oxide (CaO, known as lime ), sodium hydroxide (NaOH), and sodium carbonate (Na2 CO3)—are among the top 15 industrial chemicals in annual production. Lime is perennially in the top 10 because it is the key ingredient in construction materials such as concrete, cement, mortar, and plaster. Two other compounds, calcium chloride (CaCl2 ) and sodium sulfate (Na2 SO4 ), rank just below the top 50 in industrial importance. 

When it is heated to about 840 °C., it forms calcium oxide, CaO, by solid state reaction, vis ... 

Expanding additives improve the filtering properties of a cement [21,1720]. An expanding additive is based on calcium oxide (CaO) fired at high... 

Carbon Dioxide Separation for Fuel Reforming Carbon dioxide separation reforming in the above mentioned is one of useful methodologies for efficient hydrogen production [29]. Calcium oxide (CaO) carbonation can absorb CO2 from the reformed gas and fix it. 

Silver white, relatively soft metal that is only applied in alloys. Oxygen and water attack pure Ca. The most prominent compound is the oxide (CaO) = burnt calcium, which hardens to calcium carbonate in mortar. Annual production of about 120 million tons. Burnt gypsum (CaS04 0.5 H20) hardens with water. A great step in evolution was the replacement of hard shells of brittle calcium carbonate by an internal skeleton of tough calcium phosphate (hydroxylapatite)-protein composite. Calcium is essential for all life forms. The daily requirement is 0.7-1.0 g. Humans (70 kg) contain 1 kg of calcium. Calcium silicate is the main component of cement. Marble is calcium carbonate in polycrystalline form and the favorite material of sculptors. 

Five common desiccant materials are used to adsorb water vapor montmorillonite clay ([(Na,Cao.5)o.33(Al,Mg)2Si40io(OH)2 H20], silica gel, molecular sieves (synthetic zeolite), calcium sulfate (CaS04), and calcium oxide (CaO). These desiccants remove water by a variety of physical and chemical methods adsorption, a process whereby a layer or layers of water molecules adhere to the surface of the desiccant capillary condensation, a procedure whereby the small pores of the desiccant become filled with water and chemical action, a procedure whereby the desiccant undergoes a chemical reaction with water. 

Chemical of the Week Lime—Calcium Oxide CaO, University of Wisconsin, http //scifun.chem.wisc.edu/chemweek/lime/lime.html... 

Kamitakahara, M., Kawashita, M., Miyata, N., Kokubo, T. and Nakamura, T. (2004) Degradation of bioactive polydimethylxiloxane- CaO-SiOj-TiOj and poly(tetramethylene oxide)-CaO-Ti02 hybrids in a simulated body fluid. Journal of the American Ceramic Society, 87, 235-239. 

Determine the order of this reaction with respect to ethylene oxide at 20°C, and the value of the rate constant. The reaction goes virtually to completion, and the initial concentration of ethylene oxide (cAo) was 0.12 mol L-1. 

Titration of soil pH is an old method that is not widely used today. Basically, an acid soil suspension is prepared and titrated with a standardized base, often sodium hydroxide, although various basic calcium compounds such as calcium oxide (CaO) and calcium hydroxide [Ca(OH)2] can also be used. Because of the dark color of many soils, they are often titrated using a pH meter as the indicator of the end point. A setup for the titration of soil is shown in Figure 10.1. Titration is slow in that it takes some time after the addition of titrant for some semblance of equilibrium to be reached. Once this happens, a reading can be made or simply another addition of titrant made. 

True/False. Adding calcium oxide, CaO, to the following equilibrium will have no effect. CaC03(s) 5 CaO(s) + C02(g)... 

O Calcium oxide, CaO, reacts with carbon in the form of graphite. Calcium carbide, CaC2, and carbon monoxide, CO, are produced in an endothermic reaction. 

Today, just about all mercury is produced via the reduction of cinnabar (HgS) by using a reducing agent, such as oxygen, iron, or calcium oxide (CaO). The resulting mercury vapor is passed through water where it liquefies (changes into its normal metallic state and sinks to the bottom of the water bath) while all the impurities float to the surface. 

The neutralizing value is expressed as a percentage by weight of calcium oxide (CaO) and refers to the undried sample as received. Thus the formula becomes ... 

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