Sodium carbonate, molecular weight 105.99. The purity of chemicals is more than 99.5% (mass fraction), which is also called soda ash, but it belongs to salt, not alkali. Also known as soda or alkali ash in international trade. It is an important organic chemical raw material, mainly used in the production of flat glass, glass products and ceramic glaze. It is also widely used in domestic washing, acid neutralization and food processing.
Sodium Bicarbonate, commonly known as "baking soda", "baking soda powder" and "Chongcao", is white and fine crystals, and its solubility in water is less than that of sodium carbonate. Solids begin to decompose gradually to produce sodium carbonate, carbon dioxide and water above 50℃, and completely decompose at 270℃.
Sodium bicarbonate is an acid salt formed by neutralization of strong base and weak acid, and it is weakly alkaline when dissolved in water. This characteristic is often used as a leavening agent in food production. Sodium bicarbonate will remain sodium carbonate after the action, and too much use will make the finished product have an alkaline taste.
Extended data?
I. Physical properties of sodium carbonate
1, character
Sodium carbonate is white and odorless powder or particles at room temperature. It has water absorption, and gradually absorbs 1mol/L moisture (about = 15%) when exposed to air.
2. Solubility
Sodium carbonate is easily soluble in water and glycerol. 20g of sodium carbonate can be dissolved in 100g of water at 20℃, and the solubility is the highest at 35.4℃. In100g of water, 49.7g of sodium carbonate can be dissolved, which is slightly soluble in anhydrous ethanol and hardly soluble in propanol. The solution is alkaline and can turn phenolphthalein red.
Second, the physical properties of baking soda
Sodium bicarbonate is a white crystal or a fine crystal of opaque monoclinic system. Specific gravity 2. 15. Odorless, nontoxic, salty, soluble in water and slightly soluble in ethanol. It is soluble in 10 part of water at 25℃ and 12 part of water at about 18℃.
Its aqueous solution is slightly alkaline due to hydrolysis, stable at room temperature, easily decomposed when heated, gradually decomposed above 50℃, completely lost carbon dioxide at 270℃, unchanged in dry air, and slowly deliquesced in humid air.