Urea can be regarded as amino formamide, which has a certain weak alkalinity; When urea reacts with nitric acid and oxalic acid, etc. It forms water-insoluble salts. Urea is an organic compound composed of carbon, nitrogen, oxygen and hydrogen, also known as urea. The international common name is urea. The appearance is white crystal or powder. It is the product of protein metabolism in animals and is usually used as nitrogen fertilizer for plants.
physical features
Urea is easily soluble in water, and 105g is soluble in 100 ml water at 20℃, and the aqueous solution is neutral. There are two kinds of urea products. Crystalline urea is a white needle-like or prismatic crystal, which has strong hygroscopicity and caking after hygroscopicity, and its hygroscopic speed is 12 times faster than that of granular urea. ?
Granular urea is translucent, with a particle size of 1 ~ 2 mm, smooth in appearance and obviously improved in hygroscopicity. At 20℃, the critical moisture absorption point is 80% of the relative humidity, but at 30℃, it drops to 72.5%. Therefore, urea should be avoided to be stored in the open air in humid climate in midsummer. After adding hydrophobic substances such as paraffin wax in urea production, its hygroscopicity is greatly reduced.
Refer to the above content: Baidu Encyclopedia-Urea