Calcium oxide - a white crystalline compound.Other names of the substance - slaked lime, calcium oxide, "Killer Bee", "quicklime".Calcium oxide whose formula CaO, and its reaction product with (H2O) water - Ca (OH) 2 ("pushonka" or slaked lime) are widely used in the building trade.
How to get calcium oxide?
1. The industrial process for the preparation of the substance is thermal (due to temperature) decomposition of limestone (calcium carbonate):
CaCO3 (limestone) = CaO (calcium oxide) + CO2 (carbon dioxide)
2. Also, calcium oxideIt can be prepared by reacting the simple substances:
2Ca (calcium) + O2 (oxygen) = 2CaO (calcium oxide)
3. A third method of producing calcium oxide is thermal decomposition of calcium hydroxide (Ca (OH) 2) and calcium salts of severaloxygen-containing acids:
2Ca (NO3) 2 (calcium nitrate) = 2CaO (derived substance) + 4NO2 (nitric oxide) + O2 (oxygen)
physical properties of calcium oxide
1. Appearance: white crystalline compound.Type crystallized sodium chloride (NaCl) in the face centered cubic crystal lattice.
2. The molar mass of 55.07 grams / mole.
3. The density is 3.3 g / santimetr³.
Thermal properties of calcium oxide
1. The melting point is 2570 degrees
2. The boiling point of 2850 degrees
3. The molar heat capacity (at standard conditions) is equal to 42.06 J / (mol · K)
4.The enthalpy of formation (under standard conditions) is -635 kJ / mol
chemical properties of calcium oxide
Calcium oxide (formula CaO) - is the main oxide.Therefore, it can:
- dissolved in water (H2O), releasing energy.This forms calcium hydroxide.This reaction is as follows:
CaO (calcium oxide) + H2O (water) = Ca (OH) 2 (calcium hydroxide) + 63.7 kJ / mol;
- react with acids and acid oxides.In this form the salt.Here are some examples of reactions:
CaO (calcium oxide) + SO2 (sulfur dioxide) = CaSO3 (calcium sulfite)
CaO (calcium oxide) + 2HCl (hydrochloric acid) = CaCl2 (calcium chloride) + H2O (water).
The use of calcium oxide:
1. The main volumes of the substance under consideration used in the production of silica brick in the construction.Previously, burnt lime was used as lime cement.His was prepared with it mixed with water (H2O).The resulting calcium oxide is passed into sodium hydroxide, which is then, by absorbing atmospheric carbon dioxide (CO2), highly hardened, turning into calcium carbonate (CaCO3).Despite the low cost of this method it is now practically no lime cement used in construction, as it has a good ability to absorb and store a liquid.
2. As calcium oxide refractory material suitable inexpensive and available material.Fused calcium oxide has a resistance to water (H2O), which allowed him to use as a refractory where the use of expensive materials impractical.
3. The laboratory uses the highest calcium oxide for drying substances that do not react with it.
4. In the food industry the substance is registered as a food additive under the designation E 529 is used as an emulsifier to create a homogeneous mixture of immiscible with each other substances - water, oil and grease.
5. In industry calcium oxide is used to remove sulfur dioxide (SO2) from the flue gas.Apply, as a rule, 15% solution of water.The reaction, in which the interaction of hydrated lime and sulfur dioxide, gypsum is obtained CaCO4 and CaCO3.In the experiments, the scientists sought target of 98% cleaning up fumes from sulfur dioxide.
6. Used special "samogreyuscheysya" dishes.Vessel with a small amount of calcium oxide is disposed between the two walls of the vessel.When piercing the capsule in the water reaction begins with the release of some heat.
