In life, we often hear these two words: quicklime and hydrated lime, and many people often can't figure out which is which.
The main component of quicklime is calcium oxide (CaO), calcium carbonate (CaCO₃) can be obtained by forging calcium carbonate (CaCO₃) in a ventilated lime kiln to more than 900 ° C, and the relevant chemical equations we often use in the third grade:
CaCO3=CaO+CO2↑
The process of reacting quicklime (CaO) with water to generate calcium hydroxide, called lime curing or digestion, reacting with water (while releasing a large amount of heat), or absorbing moisture in humid air, that is, calcium hydroxide, chemical formula Ca(OH)2, commonly known as hydrated lime, extinguishing lime. The whole process is like boiling the quicklime, from which the common name comes. The popular hi pot now also uses the characteristics of calcium oxide and water reaction to exothermic a large amount, so that we can eat a mouthful of hot food anytime and anywhere. In addition, if the quicklime accidentally splashes into the eyes, it must not be rinsed with a lot of water, and too much heat generated will damage the eyes.
The chemical reaction equation is: CaO + H2O = Ca(OH)2,
Phenomenon: Experimental exothermic heat, the formation of a slightly soluble substance in water, there is a white precipitation.
Calcium hydroxide is a white powdered solid. After adding water, there are two layers, the upper aqueous solution is called clear lime water, we will often use this reagent in the third chemical, and the suspension of the lower layer is called lime milk or lime slurry. The upper layer of clear liquid clarified lime water can test carbon dioxide, and the lower layer of turbid liquid lime milk is a building material. Calcium hydroxide has a wide range of uses in production and life. Bricks can be bricked with slaked lime mixed with sand, and walls can be painted with lime paste.
Calcium hydroxide reacts with carbon dioxide in the air to form calcium carbonate that is beautiful and economical. In addition, applying lime slurry containing sulfur powder and so on to the tree can protect the tree, prevent frostbite, and prevent pests from spawning eggs. The calcium hydroxide solution reacts with a small amount of carbon dioxide
The equation is: Ca(OH)2 + CO2 = CaCO3 ↓+ H2O
Calcium hydroxide solution reacts with excess carbon dioxide,
The equation is: Ca(OH)2+2CO2=Ca(HCO3)2