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Calcium Oxide (CaO)
Quicklime and burnt lime are common names for calcium oxide, which has the chemical formula CaO. Because of its nature, physical, and chemical features, it is a white, caustic, alkaline, and crystalline chemical compound that has been widely employed in industries and pharmaceutical firms.
The chemical substance calcium oxide is specially referred to as quicklime. Free lime is calcium oxide that has passed through the production stage without reacting in building materials such as cement. It is an alkaline material that has been utilized by humans since the medieval era, earning calcium oxide the title of the oldest chemical employed by humans. It is also recognised for its physical properties, which include a medium to high rate of expansion and contraction.
Even at ceramic temperatures, the material is not volatile, making it heat resistant. It is also available in khaki and tomato red hues. Quicklime is a reasonably inexpensive mineral. Quick lime and its chemical counterpart calcium hydroxide, popularly known as lime water, are both valuable commodity chemicals.
Structure of Calcium Oxide
Calcium oxide is often produced by the thermal breakdown of minerals such as seashells or limestone. These materials contain a high concentration of calcium carbonate and are processed into calcium oxide in a lime kiln or rotary kiln. This is performed by heating the material above 1070 degrees Celsius. This is referred to as calcination or lime-burning. The heating is used to liberate a molecule of carbon dioxide, resulting in only quicklime as a product. This process begins with the thermal breakdown of materials rich in calcium carbonate, such as seashells or limestones, at high temperatures but without reaching their melting point. As we know the reaction is exothermic, carbon dioxide is produced instantly in the lime kiln. It does, however, leave behind a white caustic material known as calcium oxide. According to the Le-Chatelier principle, the carbon dioxide must be eliminated from the kiln as soon as possible. This is a reversible reaction that is also an exothermic reaction because it releases heat. The chemical process is depicted below:
CaCO3→CaO+CO2
One calcium cation with a charge of +2 and one oxygen anion with a charge of -2 make up calcium oxide. As indicated, calcium oxide decomposes into its constituent ionsCa+2 O2-
As a result, calcium oxide can be thought of as an ionic substance with an ionic link between calcium and oxygen.
When calcium oxide is exposed to water, lime water is created. This reaction, however, is very exothermic since it liberates a large quantity of heat and so produces a large volume of steam cloud. Calcium hydroxide is the resulting chemical compound. The following is an example of the reaction:
CaO + H2O → Ca(OH)2
Calcium Oxide Properties:
1.CaO has a molar mass or molecular mass of 56.0774g/mol.
2.The molecule has a density of 3.34g/cm3.
3.The standard molar entropy associated with calcium oxide is 40j/molK.
4.It is soluble in both water and glycerol.
5.It has a melting point of 2815 degrees Celsius.
6.It has a boiling point of 3098 degrees Celsius.
7.It is a chemical that is extremely stable and can tolerate high temperatures.
8.When this oxide, like all other oxides, comes into contact with acid, it forms salt.
9.When heated to temperatures exceeding 2643K, this chemical is known to create a bright glow.
Applications of Calcium Oxide
1.It is mostly employed in medicine as well as the creation of insecticides and pesticides.
2.It is used in the manufacturing of raw materials such as papers, steels, and cements.
3.It is commonly used in laboratories for chemical processes that need precipitation, dehydration, and so on.
4.Following additional reactions, the calcium oxide yields calcium compounds that are important for animal life for the creation of bones, teeth, shells, and so on.
5.It is used to identify the age of various geological strata because the accumulation of clay and lime in soil profiles demonstrates the outcome of their transfer through time.
Reactions with halogens
Calcium is very reactive towards the halogens fluorine, chlorine, bromine and iodine, and burns to form calcium(II) dihalides.
Ca(s) + F2(g) →CaF2(s)
Ca(s) + Cl2(g) → CaCl2(s)
Ca(s) + Br2(g) → CaBr2(s)
Ca(s) + I2(g) → CaI2(s)
The reactions with bromine and iodine require heat to enable the formation of the products.
Conclusion
Calcium oxide is frequently used in industry, for example, in the production of porcelain and glass, in the purification of sugar, in the preparation of bleaching powder, calcium carbide, and calcium cyanamide, in water softeners, and in mortars and cements. It is used in agriculture to remediate acidic soils.
