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Topic: Molecular weight

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In the News (Tue 19 Mar 19)

  AllRefer.com - molecular weight (Chemistry) - Encyclopedia
The molecular weight may be calculated from the molecular formula of the substance; it is the sum of the atomic weights of the atoms making up the molecule.
Molecular weights of substances may be determined experimentally in various ways, the method employed usually depending on the state (solid, liquid, or gas) of the substance.
The molecular weights of substances that are not normally gaseous and do not evaporate without decomposition are sometimes determined from their effects on the melting point, boiling point, vapor pressure, or osmotic pressure of some solvent (see colligative properties).
reference.allrefer.com /encyclopedia/M/molecwght.html   (569 words)

 Molecular mass - Wikipedia, the free encyclopedia
The molecular mass of a substance (less accurately called molecular weight and abbreviated as MW) is the mass of one molecule of that substance, relative to the unified atomic mass unit u (equal to 1/12 the mass of one atom of carbon-12).
Molecular mass or molar mass are used in stoichiometry calculations.
Thus the molecular weight of calcium carbonate is 100 therefore the gram-molecular weight is 100 g.
www.wikipedia.org /wiki/Molecular_mass   (383 words)

 Molecular Weight   (Site not responding. Last check: 2007-11-07)
The weight of a molecule is the sum of the weights of the atoms of which it is made.
The unit of weight is the dalton, one-twelfth the weight of an atom of
a mole is the quantity of a substance whose weight in grams in equal to the molecular weight of the substance.
users.rcn.com /jkimball.ma.ultranet/BiologyPages/M/Mole.html   (494 words)

 Atomic and Molecular Mass   (Site not responding. Last check: 2007-11-07)
Weight is the pull of gravity on an object's mass, so it varies from location to location on earth, though it's not a great variation.
There is no possible way to measure the weight of an atom since it is far too small to be measured on the most sensitive of scales.
The weight of the empty beaker is 145.68 g.
www.carlton.paschools.pa.sk.ca /chemical/molemass/moles1.htm   (309 words)

 Low molecular weight heparin or unfractionated heparin in the treatment of patients with uncomplicated deep vein ...
Subcutaneous low weight molecular weight heparin compared with continuous intravenous heparin in the treatment of proximal vein thrombosis.
A comparison of low molecular weight heparin administered primarily at home with unfractionated heparin administered in the hospital for proximal vein thrombosis.
Comparison of low molecular weight heparin, administered primarily at home, with unfractionated heparin, administered in hospital and subcutaneous heparin administered at home for deep vein thrombosis.
emj.bmjjournals.com /cgi/content/full/17/6/402   (410 words)

 CHEMTUTOR ATOMIC STRUCTURE   (Site not responding. Last check: 2007-11-07)
The formula weight is the most general term that includes atomic weight and molecular weight.
The molecular weight of HCl is 36.461 g/mol, the sum of the atomic weights of hydrogen and chlorine.
The way to calculate the molecular weight of any formula is to add up the atomic weights of all the atoms in the formula.
www.chemtutor.com /struct.htm   (4244 words)

 Molecular Weight Calculator
ChemicaLogic's Molecular Weight Calculator is a free add-in for spreadsheets that you can use to calculate the molecular weight of chemicals.
Molecular weight calculator recognizes over 100 atomic species and uses the standard IUPAC atomic weights.
Try out the Molecular Weight Java Applet which is an on-line version of the popular Molecular Weight Calculator.
www.chemicalogic.com /mwcalc   (90 words)

 Number Average and Weight Average Molecular Weight for Macrogalleria
The number average molecular weight is the total weight of the sample divided by the number of molecules in the sample.
For weight fraction of one type of molecule, it is the weight of that type of molecule divided by the total weight of the sample.
The distribution of molecular weights in a polymer sample is often described by the ratio of the weight average molecular weight to the number average molecular weight.
www.pslc.ws /macrog/activity/average.htm   (516 words)

 Low molecular weight heparins in medicine and anaesthesia
Therefore, the FDA has asked all manufacturers of low molecular weight heparins and heparinoids to revise their package inserts to provide further information for the safe and effective use of these drugs.
When neuraxial anesthesia (epidural/spinal anesthesia) or spinal puncture is employed, patients anticoagulated or scheduled to be anticoagulated with low molecular weight heparins or heparinoids for prevention of thromboembolic complications are at risk of developing an epidural or spinal hematoma which can result in long-term or permanent paralysis.
Low Molecular Weight Heparins (LMWH) are at least as effective as unfractionated heparin (UFH) in the prevention of deep venous thrombosis and subsequent embolism.
www.4um.com /tutorial/currents/lmwh.htm   (2719 words)

 Conjugates of superoxide dismutase coupled to high molecular weight polyalkylene glycols (US5006333)
Preferred is a PAG with an average molecular weight of about 40,000 or greater but no greater than 200,000 and especially preferred is an average molecular weight for the PAG of about 40,000-150,000.
However, the molecular weight of the PAG polymer used for the preparation of the conjugate in the present invention is greater than 20,000 and preferably in the 35,000 to 200,000 MW range and especially about 40,000 to 150,000.
Thus, by using fewer strands of high molecular weight PAG, as in the present invention, the adducts retain most, if not substantially all of the activity of the parent molecule, while also demonstrating increased persistence in the bloodstream.
www.delphion.com /details?pn=US05006333__   (2473 words)

 Molecular Weight of a Volatile Compound
The ideal gas law serves as the basis for the Dumas Method for the determination of molecular weight.
Thus, the molecular weight of an ideal gas can be calculated if its mass, pressure, temperature, and volume are known.
In the Dumas Method a small volume of the liquid compound whose molecular weight is to be determined is placed in a flask of known mass and volume.
wwwchem.csustan.edu /chem1102/molwt.htm   (759 words)

 ChemTeam: Molecular Weight
The molecular weight of a substance is the weight in atomic mass units of all the atoms in a given formula.
The molecular weight of a substance is needed to tell us how many grams are in one mole of that substance.
Also, atomic weight values are periodically redetermined and refined and this may contribute to minor differences in the weights used.
dbhs.wvusd.k12.ca.us /webdocs/Mole/MolecWt.html   (770 words)

 Molecular-weight-dependent effects of nonanticoagulant heparins on allergic airway responses -- Campo et al. 86 (2): ...
It has been suggested that the antiallergic activity of inhaled fractionated heparins is molecular weight dependent (32).
molecular weight of fractionated heparins was observed (32).
Immunologic mast cell-mediated responses and histamine release are attenuated by heparin.
www.jap.org /cgi/content/full/86/2/549   (4885 words)

 Molecular weight calculations
The relative molecular weight of the substance will be defined as the sum of relative atomic weights of the elements, multiplied by the number of atoms in the formula of this substance.
For example, when manual calculating the relative molecular weight of lead-nitrate, you must type the correct chemical formula.
Sum of weights of the each elements give relative molecular weight of the lead-nitrate.
www.ktf-split.hr /periodni/en/calculator.html   (609 words)

 Linux4Chemistry - Linux software for chemistry: molecular modeling, visualization, graphic, quantum mechanic, dynamic, ...   (Site not responding. Last check: 2007-11-07)
Molecular modeling software package which allows the user to construct and graphically manipulate both simple and complex chemical structures, to apply molecular mechanics and dynamics techniques to evaluate the energies and geometries of molecules in vacuo or in solution, and to display and examine graphically the results of the modeling calculations.
Molecular Operating Environment is a unique and flexible software system designed specifically for chemical computing with two run-time variants of MOE: MOE the full graphical interface used by methods developers, computational experts and occasional modeling users, and MOE/batch intended for use on contended for use on compute, Web and database servers.
YASARA is an interactive real-time molecular dynamics program, covering a wide range of topics in the rapidly growing field of structural bioinformatics: Molecular visualization, protein folding (based on any amount of information available: from sequence alone to fully assigned NMR spectra), docking and parallel macromolecular dynamics.
zeus.polsl.gliwice.pl /~nikodem/linux4chemistry.html   (9678 words)

 Synthesis high-molecular-weight epoxy resins under microwave irradiation
Abstract: A new method of synthesis of high molecular weight epoxy resins is presented.
Schematic reaction of synthesis of high molecular weight epoxy resins is shown in Figure 1.
It is necessary to use an atmosphere of nitrogen to improve the colour of the synthesised epoxy resins.
www.mdpi.net /ecsoc-5/e0035/e0035.htm   (694 words)

 Molecular Weight Lab   (Site not responding. Last check: 2007-11-07)
To determine the molecular weight of a volatile liquid.
An inherent error in determining the unknown's molecular weight is the design of the apparatus: the boiling water bath does not envelop the upper part of the Erlenmeyer flask.
From the class values listed on the chalkboard for the molecular weight of the unknown liquid determine which ones would be considered outliers at the 96% confidence level and rejected.
chem.lapeer.org /Chem2Docs/Dumas.html   (791 words)

 The MSDS HyperGlossary: Mole
The mole is simply a convenient unit for dealing with large numbers just like it is easier to talk about the weight of a ship in tons rather than ounces.
of a substance is the sum of the atomic weights of each atom in the chemical formula.
The formula and molecular weights are also included on MSDS's in case one needs to calculate a molarity, for example.
www.ilpi.com /msds/ref/mole.html   (582 words)

 Prevention of Exercise-induced Bronchoconstriction by Inhaled Low-molecular-weight Heparin -- AHMED et al. 160 (2): 576 ...
weight and the antiallergic activity was observed (20).
Many biological actions of heparin are molecular weight dependent (6, 18, 22).
Molecular weight-dependent effects of non-anticoagulant heparins on allergic airway responses.
www.ajrccm.org /cgi/content/full/160/2/576   (3609 words)

 High molecular weight caldesmon positive stromal cells in the capsule of thyroid follicular tumours and tumour-like ...
High molecular weight caldesmon positive stromal cells in the capsule of thyroid follicular tumours and tumour-like lesions -- Nakayama et al.
High molecular weight caldesmon positive stromal cells in the capsule of thyroid follicular tumours and tumour-like lesions
Expression of high molecular weight caldesmon during phenotypic modulation of smooth muscle cells.
jcp.bmjjournals.com /cgi/content/full/55/12/917   (2008 words)

 Molecular Weight Forms of Inhibin A and Inhibin B in the Bovine Testis Change with Age -- Kaneko et al. 68 (5): 1918 -- ...
molecular weight forms of inhibin present in the testis [20].
Molecular weight distribution of total inhibin, inhibin A, and inhibin B in bull testes at 4–5 (a), 31–32 (b), and 49–56 (c) wk of age.
The vertical broken lines represent molecular weights and positions of marker proteins used to calibrate the gel.
www.biolreprod.org /cgi/content/full/68/5/1918   (4767 words)

 Conjugation of Low-Molecular-Weight Heparin and Deoxycholic Acid for the Development of a New Oral Anticoagulant Agent ...   (Site not responding. Last check: 2007-11-07)
subtracting the molecular weight of heparin from the molecular
the bioactivity of heparin with respect to its molecular weight.
As the molecular weight decreased, the bioactivity measured
circ.ahajournals.org /cgi/content/full/104/25/3116   (3017 words)

 Domain 5 of high molecular weight kininogen (kininostatin) down-regulates endothelial cell proliferation and migration ...
Plasma HK (high molecular weight kininogen) is coded for by a single gene.
High molecular weight kininogen inhibits thrombin-induced platelet aggregation and cleavage of aggregin by inhibiting binding of thrombin to platelets.
High molecular weight kininogen peptides inhibit the formation of kallikrein on endothelial cell surfaces and subsequent urokinase-dependent plasmin formation.
www.bloodjournal.org /cgi/content/full/95/2/543   (6143 words)

 Encyclopedia: Molecular weight   (Site not responding. Last check: 2007-11-07)
Updated 244 days 11 hours 18 minutes ago.
For example: the atomic mass of hydrogen is 1.00784 u and that of oxygen is 15.9994 u; therefore, the molecular mass of water with formula H
Click for other authoritative sources for this topic (summarised at Factbites.com).
www.nationmaster.com /encyclopedia/Molecular-weight   (236 words)

 molecular formula
The search can be interrupted part way through, and the elements which have been fully investigated will be listed.
The test is approximate, and is likely to allow some improbable molecules.
The data for atomic weights and isotope distributions can be examined using the periodic table applet.
www.ch.cam.ac.uk /magnus/EadFormW.html   (118 words)

 Molecular Weight Search
Note: This search is by molecular weight based on single (most-abundant) isotope atomic masses.
These weights may vary significantly from molecular weights based on average atomic masses.
The molecular weights reported elsewhere in this site are based on average atomic masses.
webbook.nist.gov /chemistry/mw-ser.html   (295 words)

 Current trends in the management of thromboembolic events -- De Lorenzo et al. 94 (4): 179 -- QJM
Low molecular weight heparin vs regular heparin or aspirin in the treatment of unstable angina and silent ischaemia.
Subcutaneous low molecular weight heparin with continuous intravenous heparin in the treatment of proximal vein thrombosis.
A comparison of low molecular weight heparin administered primarly at home with unfractionated heparin administered in the hospital for proximal deep-vein thrombosis.
qjmed.oupjournals.org /cgi/content/full/94/4/179   (3336 words)

 Amazon.com: Books: Determination of Molecular Weight   (Site not responding. Last check: 2007-11-07)
Presents the state-of-the-art in molecular weight distribution of polymeric materials.
First chapter covers the concepts of molecular averages and distribution functions for polydisperse polymer systems.
Following chapters cover all the modern techniques for determining molecular weight, including classical light scattering, x-ray scattering, neutron scattering, use of the ultracentrifuge, viscometric determination, viscoelastic measurements, fractionation techniques, chromatographic techniques, mass spectrometry, as well as methods for characterizing insoluble polymers.
www.amazon.com /exec/obidos/tg/detail/-/0471058939?v=glance   (544 words)

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