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B. F
B is the second letter of the Latin alphabet. B may also refer to: Science, technology, and mathematics Astronomy * Astronomical objects in the Barnard list of dark nebulae (abbreviation B) * Latitude (''b'') in the galactic coordinate system Biology and medicine * Haplogroup B (mtDNA), a human mitochondrial DNA (mtDNA) haplogroup * Haplogroup B (Y-DNA), a Y-chromosomal DNA (Y-DNA) haplogroup * Blood type B * ATC code B ''Blood and blood forming organs'', a section of the Anatomical Therapeutic Chemical Classification System * Vitamin B * Hepatitis B * Berlin Botanical Garden and Botanical Museum, assigned the abbreviation B as a repository of herbarium specimens Computing * B (programming language) * B-Method, for computer software development * B-tree, a data structure * Bit (b) * Byte (B) * , an HTML element denoting bold text Physical and chemical quantities and units * One of the reciprocal lattice vectors (''b*'') * Breadth (''b''); see length * Impact parameter ( ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
List Of Dark Nebulae
This is a list of dark nebulae (absorption nebulae), also called "dark clouds". List *E Nebula ( Barnard 142 and 143) *Barnard 68, possibly the closest to Earth at about 400 light-years. *Bernes 157 (Sandqvist and Lindroos, SL 39-41), another close dark nebula of the Corona Australis Molecular Cloud, which includes NGC 6729 Named absorption nebulae See also the references to names from other cultures at dark cloud constellations: *Coalsack Nebula *Cone Nebula *Dark Doodad Nebula * Dark Horse Nebula *Horsehead Nebula ( Barnard 33) *Pipe Nebula (also see Dark Horse Nebula; includes Barnard 59, 77 and 78) * Snake Nebula (also see Dark Horse Nebula) * Keyhole Nebula Barnard objects See also *Lists of astronomical objects *Nebula *Dark nebulae * Bok globules External linksEast Valley Astronomical Society Barnard Dark Nebulae Observing Program [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Molality
Molality is a measure of the number of moles of solute in a solution corresponding to 1 kg or 1000 g of solvent. This contrasts with the definition of molarity which is based on a specified volume of solution. A commonly used unit for molality in chemistry is Mole (unit), mol/kilogram, kg. A solution of concentration 1 mol/kg is also sometimes denoted as ''1 molal''. The unit ''mol/kg'' requires that molar mass be expressed in ''kg/mol'', instead of the usual ''g/mol'' or ''kg/kmol''. Definition The molality (''b''), of a Solution (chemistry), solution is defined as the amount of substance (in mole (unit), moles) of solute, ''n''solute, divided by the mass (in kg) of the solvent, ''m''solvent: :b = \frac In the case of solutions with more than one solvent, molality can be defined for the mixed solvent considered as a pure pseudo-solvent. Instead of mole solute per kilogram solvent as in the binary case, units are defined as mole solute per kilogram mixed solvent. Ori ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
