Search results
Results From The WOW.Com Content Network
The combination of urea and ammonium nitrate has an extremely low critical relative humidity (18% at 30 °C) and can therefore only be used in liquid fertilizers. The most commonly used grade of these fertilizer solutions is UAN 32.0.0 (32%N) known as UN32 or UN-32, which consists of 45% ammonium nitrate, 35% urea and only 20% water. Other ...
The soil's pH also has a strong effect on the amount of volatilization. Specifically, highly alkaline soils (pH~8.2 or higher) have proven to increase urea hydrolysis. One study has shown complete hydrolysis of urea within two days of application on such soils. In acidic soils (pH 5.2) the urea took twice as long to hydrolyze. [7]
The structure of the molecule of urea is O=C(−NH 2) 2.The urea molecule is planar when in a solid crystal because of sp 2 hybridization of the N orbitals. [8] [9] It is non-planar with C 2 symmetry when in the gas phase [10] or in aqueous solution, [9] with C–N–H and H–N–H bond angles that are intermediate between the trigonal planar angle of 120° and the tetrahedral angle of 109.5°.
Urea is highly soluble in water and is therefore also very suitable for use in fertilizer solutions (in combination with ammonium nitrate: UAN), e.g., in 'foliar feed' fertilizers. For fertilizer use, granules are preferred over prills because of their narrower particle size distribution, which is an advantage for mechanical application.
UAN is a solution of urea and ammonium nitrate in water used as a fertilizer. Uan or UAN may also refer to: Adapa, an alternate name for the first of the Mesopotamian seven sages; Autonomous University of Nayarit (in Spanish: Universidad Autónoma de Nayarit), a Mexican public university based in the city of Tepic, Nayarit
These can be called urea adducts or if a solvent is involved, a urea solvate, and the process is called urea extraction crystallization. Urea can also be a neutral ligand if it is coordinated to a central metal atom. Urea can form hydrogen bonds to other oxygen and nitrogen atoms in the substance it crystallises with.
1,1-Dimethylurea (DMU) is a urea derivative used as a polar solvent and a reagent in organic reactions. It is a solid, but forms a eutectic with a low melting point in combination with various hydroxylic additives that can serve as a environmentally sustainable solvent for various chemical reactions.
Biotin, a water-soluble B vitamin, is a bicyclic urea.. In chemistry, ureas are a class of organic compounds with the formula (R 2 N) 2 CO where R = H, alkyl, aryl, etc. Thus, in addition to describing the specific chemical compound urea ((H 2 N) 2 CO), urea is the name of a functional group that is found in many compounds and materials of both practical and theoretical interest.