molecular weight

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Related to molecular weights: Molar mass

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.

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.

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.

molecular weight

The sum of the weights of all the atoms in the molecule.

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.
References in periodicals archive ?
Peanut allergens: By comparing proteins in the peanut extracts with the allergen database on the basis of their molecular weights, a protein of 64 KDa was found as Ara h 1 Cupin (Vicillin-type 7S globulin).
Toward this end, studies on the extent to which polymers' physical properties, such as [T.sub.g], molecular weight, and chemical structure, influence the process of interface formation and interfacial thickness are necessary.
The drug could cause human fetal harm based on the animal data, mechanism of action, relatively low molecular weight (about 556), and terminal half-life (17 hours).
Because of this, commercial plastics have polymers with a molecular weight distribution.
In the DPPH assay, the free radical scavenging activity of the high molecular weight chitosan (39 g of Trolox equivalent per ml) was higher than that of the low molecular weight chitosan (31.2 g of Trolox equivalent per ml).
Controlling molecular weight and molecular weight distribution is crucial because of the influence these parameters have on a range of polymer properties.
Repetition of this process results in a molecule of high molecular weight. Such a process is called addition polymerization.
High molecular weight polyesters are desired in many applications.
The results from the one-dimensional SDS-PAGE revealed the existence of high molecular weight bands that the scientists suspected to be plasminogen.
argentatum, from the Asteridae, because it was known to provide one of the simplest rubber-producing systems known; and Ficus elastica Roxb., from the Dilleniidae, because it was readily available, easy to grow and produces a lower molecular weight, poorer quality polymer.
Figure 4 shows the changes of absolute weight average molecular weights ([M.sub.w.MALLS]) and polydispersities (PDI = [M.sub.w]/[M.sub.n]) with MA conversion.
Metallocene catalysis provides precise control of molecular weight and low levels of catalyst and residual monomer, says McNally.

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