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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 usually spread at rates of between 40 and 300 kg/ha (35 to 270 lbs/acre) but rates vary. Smaller applications incur lower losses due to leaching. During summer, urea is often spread just before or during rain to minimize losses from volatilization (a process wherein nitrogen is lost to the atmosphere as ammonia gas).
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.
Molecular weight (M.W.) (for molecular compounds) and formula weight (F.W.) (for non-molecular compounds), are older terms for what is now more correctly called the relative molar mass (M r). [8] This is a dimensionless quantity (i.e., a pure number, without units) equal to the molar mass divided by the molar mass constant .
Ammonium carbamate is an intermediate in the industrial production of urea. A typical industrial plant that makes urea can produce up to 4000 tons a day. [15] in this reactor and can then be dehydrated to urea according to the following equation: [14] [NH 2 CO 2][NH 4] → (NH 2) 2 CO + H 2 O
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.
The molecular weight is either 480 kDa or 545 kDa for jack-bean urease (calculated mass from the amino acid sequence). 840 amino acids per molecule, of which 90 are cysteine residues. [ 10 ] The optimum pH is 7.4 and optimum temperature is 60 °C.
The second number ("P value") is the percentage by weight of phosphorus pentoxide P 2 O 5. The third number ("K value") is the equivalent content of potassium oxide K 2 O. [3] For example, a 15-13-20 fertilizer would contain 15% by weight of nitrogen, 13% by weight of P 2 O 5, 20% by weight of K 2 O, and 52% of some inert ingredient.