molecular weight

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weight

 [wāt]
1. heaviness; the degree to which a body is drawn toward the earth by gravity. (See also Tables of Weights and Measures in the Appendix.) Abbreviated wt.
2. in statistics, the process of assigning greater importance to some observations than to others, or a mathematical factor used to apply such a process.
apothecaries' weight see apothecaries' system.
atomic weight the sum of the masses of the constituents of an atom, expressed in atomic mass units (or daltons), in SI units (i.e., kilograms), or as a dimensionless ratio derived by comparing the mass to the mass of an atom of carbon-12, which is taken as 12.000. Abbreviated At wt.
avoirdupois weight see avoirdupois system.
equivalent weight the amount of substance that combines with or displaces 8.0 g of oxygen (or 1.008 g of hydrogen), usually expressed in grams; for acid/base reactions, one equivalent donates or receives a mole of protons and the equivalent weight is the ratio of the molecular weight to the number of protons involved in the reaction. For oxidation-reduction reactions, one equivalent donates or receives a mole of electrons and the equivalent weight is the ratio of the molecular weight to the number of electrons involved in the reaction.
gram molecular weight the molecular weight of a substance expressed in grams; one gram molecular weight of a molecular substance contains one mole of molecules. See also mole1.
low birth weight (LBW) see under infant.
molecular weight the weight of a molecule of a chemical compound as compared with the weight of an atom of carbon-12; it is equal to the sum of the weights of its constituent atoms and is dimensionless. Abbreviated Mol wt or MW. Although widely used, the term is not technically correct; relative molecular mass is preferable.
very low birth weight (VLBW) see under infant.
Miller-Keane Encyclopedia and Dictionary of Medicine, Nursing, and Allied Health, Seventh Edition. © 2003 by Saunders, an imprint of Elsevier, Inc. All rights reserved.

mo·lec·u·lar weight (mol wt, MW),

the sum of the atomic weights of all the atoms constituting a molecule; the mass of a molecule relative to the mass of a standard atom, now 12C (taken as 12.000). Relative molecular mass (Mr) is the mass relative to the dalton and has no units.
See also: atomic weight.
Farlex Partner Medical Dictionary © Farlex 2012

mo·lec·u·lar weight

(mŏ-lekyū-lăr wāt)
The sum of the atomic weights of all the atoms constituting a molecule; the mass of a molecule relative to the mass of a standard atom, now 12C (taken as 12.000). Relative molecular mass (Mr) is the mass relative to the dalton and has no units.
See also: atomic weight
Synonym(s): molecular weight ratio, relative molecular mass.
Medical Dictionary for the Health Professions and Nursing © Farlex 2012

molecular weight

The sum of the weights of all the atoms in the molecule.
Collins Dictionary of Medicine © Robert M. Youngson 2004, 2005

mo·lec·u·lar weight

(mol wt, MW) (mŏ-lekyū-lăr wāt)
The sum of the atomic weights of all the atoms constituting a molecule.
Synonym(s): molecular weight ratio, relative molecular mass.
Medical Dictionary for the Dental Professions © Farlex 2012
References in periodicals archive ?
Results were presented in a table showing number-average molecular weights, polydispersity and conversion after 5 h at 135[degrees]C.
where N is the Avogadro's number = 6.02268 x [10.sup.23] [mol.sup.-1], M is the number-average molecular weight of the compatibilizer.
Composition of SB Molecular structure [bar.M.sub.n SB] (a) (g/mol) PS/PB:10/90 SB-1 399,000 PS/PB:30/70 SB-2 233,000 PS in block Composition of SB [bar.P.sub.n SB] (b) Total PS (wt%) (wt%) PS/PB:10/90 SB-1 7,015 10.2 6.6 PS/PB:30/70 SB-2 3,633 32.6 25.4 (a) [bar.M.sub.n SB]: Number-average molecular weight of SB copolymer.
When the chains are terminated via both combination and disproportionation, the number-average molecular weight [bar.M.sub.n] (I,J) of the polymer chains produced on node (I,J) can be expressed as
A number-average molecular weight (i.e., [bar.M.sub.n]) of the ENR molecules was also determined using Gel Permeation Chromatograph (GPC), model Waters 1525 (Waters Corporation, USA).
The average molecular weights, such as the number-average molecular weight [M.sub.n] and the weight-average molecular weight [M.sub.w], were determined by a gel permeation chromatographic method as a linear polyethylene standard, and the number of long ([greater than or equal to]C6) branches per 1000 carbon atoms was evaluated by nuclear magnetic resonance.
The water-soluble resins have number-average molecular weights of 40,000-100,000 and excellent solubility in aqueous alkaline solutions.
The number-average molecular weights (([M.sub.n]) of all the liquid rubbers were determined using a Knauer Vapor Pressure Osmometer (VPO), with toluene as the solvent and benzil as a standard.
Table 1 displays the weight-and number-average molecular weights of the four original polyethylenes and the new materials obtained after modifying the polymers with different amounts of peroxide.