
	Where results make sense

Topic: Molecular mass

Related Topics

Kilodalton

Molecular weight

Atomic mass unit

Mole (unit)

Molar gas constant

Pyrrole

Simplified molecular input line entry specification

Relative density

Density

Stoichiometry

Phenol

Biochemistry

CAS registry number

Litre

Indole

In the News (Tue 14 Feb 12)

EXECUTIVE POWER

Iran

ANALYSIS

Pakistan

Family compact

	Molecular Mass
		In theory, the relative molecular mass or molecular weight of a compound is the mass of a molecule of the compound relative to the mass of a carbon atom taken as exactly 12.
		In practice, the molecular mass, MM, (molecular weight, MW) of a compound is the sum of the atomic masses (atomic weights) of the atomic species as given in the molecular formula.
		Calculate the Molecular Mass (MM) of the compound carbon dioxide, CO The formula for carbon dioxide is composed of one atom of carbon and two atoms of oxygen
	www.ausetute.com.au /mmcalcul.html (875 words)

	Molecular mass
		The molecular mass of a substance (less accurately called molecular weight and abbreviated as MW) is the mass of one molecule of that substance and is expressed in terms of the molecular mass unit u (equal to 1/12 the mass of one atom of carbon-12).
		The molecular mass can be calculated as the sum of the atomic masses of all the atoms of any one molecule.
		Strictly speaking, the molecular mass is not precisely equal to the sum of the atomic masses, but a little bit lower.
	www.ebroadcast.com.au /lookup/encyclopedia/mo/Molecular_mass.html (184 words)

	Molecular Mass - nCyclopedia
		The molecular mass (abbreviated MM) of a substance, 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).
		Due to this relativity, the molecular mass of a substance is commonly referred to as the relative molecular mass, and abbreviated to M
		The masses used to compute the monoisotopic molecular mass are found on a table of isotopic masses and are not the same as found on a typical periodic table.
	nanotitan.com /nCyclopedia/molecularMass.htm (473 words)

	Molecular mass Summary
		Due to this relativity, the molecular mass of a substance is commonly referred to as the relative molecular mass, and abbreviated to Mr.
		In mass spectrometry, the molecular mass of a small molecule is usually reported as the monoisotopic mass, that is, the mass of the most common isotope of each element.
		Molecular mass or molar mass are used in stoichiometry calculations.
	www.bookrags.com /Molecular_mass (1878 words)

	Molar Mass of Magnesium
		Masses of atoms are measured relative to the mass of the carbon-12 isotope, which itself is defined to have a mass of exactly 12 atomic mass units (or amu).
		The mass spectrometer is a device used to measure the mass of an atom by reading on a detecting screen the amount of deflection their +1 ions experience in a magnetic field: the smaller the deflection the larger the mass.
		Likewise, the mass of one mole of molecules is the molecular mass expressed in grams.
	ch185.semo.edu /molmassmg/enter.html (837 words)

	Mass Spectrometry
		The highest-mass ion in a spectrum is normally considered to be the molecular ion, and lower-mass ions are fragments from the molecular ion, assuming the sample is a single pure compound.
		The molecular ion is the strongest ion in the spectra of CO and C
		The masses of molecular and fragment ions also reflect the electron count, depending on the number of nitrogen atoms in the species.
	www.cem.msu.edu /~reusch/VirtualText/Spectrpy/MassSpec/masspec1.htm (2839 words)

	Untitled Document
		The observed molecular mass is in good agreement with the theoretical molecular mass of hen egg lysozyme (based on average atomic masses) of 14305.14 Da.
		The mass profile is dominated by a component of molecular mass 14,305.7 Da, with a series of minor peaks at higher mass, which is usually indicative of salt adducting e.g.
		The mass accuracy depends on the type and performance of the analyser of the mass spectrometer, but most modern instruments should be capable of measuring masses to within 0.01% of the molecular mass of the sample, at least up to ca.
	www.astbury.leeds.ac.uk /facil/MStut/mstutorial.htm (5863 words)

	Molecular Mass
		Protons and neutrons have the same mass, so we usually measure the mass of an atom in units of mass that are equal to the mass of one proton, or one neutron.
		Since we can easily get the atomic mass of any atom from the periodic table, it is simple to calculate the molecular mass of a molecule.
		Molecular mass — learn how molecular mass can be a lot more complicated for macromolecules than for small molecules, part of The Macrogalleria from the University of Southern Mississippi.
	www.chemheritage.org /EducationalServices/faces/poly/tutorial/weight.htm (401 words)

	Molar Mass Conversion Factors Help
		The first step in the determination of the molar mass of a molecular compound is to determine the molecular mass of the compound, which is the weighted average mass of the compound’s naturally occurring molecules.
		The number of grams in the molar mass (grams per mole) of a molecular compound is the same as its molecular mass.
		The first step in the determination of the molar mass of an ionic compound is to determine its formula mass, which is the weighted average of the mass of the naturally occurring formula units of the substance.
	www.mpcfaculty.net /mark_bishop/molar_mass_conversion_factors_help.htm (560 words)

	CHEMystery: Chemical Reactions: Empirical and Molecular Formulas (Site not responding. Last check: )
		The molecular, or formula mass of a substance is the sum of all the atomic masses which compose the molecule.
		The gram molecular mass of a compound is the mass (in grams) which equals the molecular mass.
		For CH, the molecular mass is 13 (12 + 1).
	library.thinkquest.org /3659/chmreact/formula.html (416 words)

	BioMed Central \| Full text \| Low molecular mass dinitrosyl nonheme-iron complexes up-regulate noradrenaline release in ...
		There are high molecular mass (protein-bound) and low molecular mass DNIC, paramagnetic and diamagnetic DNIC [9].
		We hypothesised, that low molecular mass DNIC may also affect the process of neuromediator release, which is known to be associated with membrane depolarisation and involves an array of thiol-containing proteins which are usually sensitive to S-nitrosation [13,14].
		Since low molecular mass DNIC were shown to be much more potent S-nitrosative agents than low molecular mass S-nitrosothiols and NO [5], this scenario appears to be very likely.
	www.biomedcentral.com /1471-2210/2/3 (2934 words)

	Mass Spectrometry Glossary : SHIMADZU (Shimadzu Corporation) (Site not responding. Last check: )
		Using a reverse double-focusing mass spectrometer with a magnetic field → electric field sequence, the precursor ions pass through a fixed magnetic field and are then scanned in the electric field to produce the spectrum.
		Normally, 2 mass spectrometers are connected and a specific ion (precursor ion), from among the molecular and fragment ions generated at the ion source, is selectively passed through the first instrument.
		The molecular weight of a molecular compound is an average value and is determined by measuring the mass and proportion of isotopes of the compound using a mass spectrograph.
	www1.shimadzu.com /products/lab/mass/m.html (1410 words)

	Intro to Mass Spectrometry
		The mass spectrometer measures the mass to charge ratio of individual ions commonly written as m/z where m is the mass in amu and z is the charge in units of the charge of a proton.
		Because the mass spectrometer measures the mass to charge ratio of individual ions, the molecular masses are measured by the mass spectrometer for all possible isotopic compositions at natural abundance.
		The peak at m/z=44 is the molecular ion and the peak at m/z=45 is an isotope peak for the molecular ion.
	orgchem.colorado.edu /hndbksupport/ms/atomiso.html (723 words)

	UNM Mass Spectrometry : MS Tutorial
		The level of mass accuracy achieved with this approach would be useful for identifying proteins via peptide mass database searching where the higher mass accuracy will increase the specificity of the identification.
		For large molecular weight biomolecules (e.g., proteins), it is important to recognize that the measured mass is the average mass and that the peak envelope extends over many individual masses.
		The only required input for Maximum Entropy processing is the expected molecular mass range of the compound of interest and an estimate of the peak width for a compound of that mass range with the number of charges needed to produce the observed multi-charged spectrum.
	massspec.unm.edu /ms.htm (1509 words)

	6.1 Molecular Mass (Site not responding. Last check: )
		One of the most important pieces of information a chemist seeks for identification of an unknown is the molar mass of the compound.
		If the mass spectrometer is being used to confirm an identity, the molecular mass should be computed for the proposed structure.
		Measurement of the molecular mass via EI mass spectrometry can get tricky; chemical ionization is a technique that offers less ambiguity in molecular mass assignment.
	www.dsbscience.com /freepubs/forensic_intern/node59.html (106 words)

	ms
		As mass spectrometers separate isotopes, it is necessary to calculate molecular masses using the masses of the most common isotopes rather that the averages that appear in the periodic table.
		Thus the highest molecular mass peak in a spectrum may be from a isotopic molecular ion and not strictly definable as the molecular ion.
		Loss of fragments of molecular mass 3 - 14 are extremely rare and fragments at P - 3 to P - 14 should lead to suspicion of the molecular ion.
	virtual.yosemite.cc.ca.us /smurov/ms.htm (1534 words)

	Office of Research & Sponsored Programs
		Mass of the unknown peptide/protein is deduced by averaging a requisite number of individual TOF measurements (20-1000, obtained by repeated laser firings at up to 20 times per second) and referenced to calibration standards of known mass.
		Since mass spectrometers measure mass to charge ratio, not molecular mass per se, a pure protein gives multiple peaks on a quadrupole MS instrument, corresponding to one for each of its charge states.
		This service is for analysis of peptide molecular mass (crude synthetic or purified), where the user provides 10 pmol of peptide as a solid or solution (µM) without significant buffer or detergent contamination.
	www.med.cornell.edu /research/rea_sup/mass_spec.html (1414 words)

	Protein Mass Spectrometry - Molecular Weight Determination (Site not responding. Last check: )
		Molecular weights of proteins in excess of 10,000 daltons have been successfully determined on this magnetic sector type instrument using FAB ionization.
		The probe is then inserted into the mass spectrometer and the sample bombarded with high energy cesium ions to sputter off intact (usually protonated) molecular ions of the protein in the sample.
		Since mass spectrometers normally measure mass to charge ratio, increasing the number of charges on the ion effectively multiplies the mass range of the instrument.
	www2.musc.edu /Pharm/msgb.html (724 words)

	FAQs
		The mass of the molecular ion is essentially the same as that of the neutral molecule.
		The monoisotopic mass is obtained by summing the isotopic masses of the most abundant naturally occurring stable isotopes of the elements contributing to a molecule.
		The nominal mass of a molecule is the mass derived from the sum of the integer masses of the most abundant naturally occurring stable isotopes.
	www1.wfubmc.edu /mass_spec/FAQs.htm (670 words)

	Mass Spectrometry (Site not responding. Last check: )
		Note that molecular weight, or more correctly formula weight (the mass in grams of one mole of compound), is actually a weighted average of the molecular masses of all the isotopic variants of a given molecule.
		For small organic compounds a mass spectrometer can resolve the individual "isotopomers" and the mass of the major one (the so-called mono-isotopic mass) is very close to the formula weight of the compound.
		All mass spectrometers consist of three basic components, a source for producing ions to analyze, a mass analyzer for separating ions according to their m/z ratios, and a detector for counting the ions (usually a simple photomultiplier tube connected to a computer).
	www.brsl.ku.edu /bioms2.htm (798 words)

	Relative Molecular Mass (Site not responding. Last check: )
		A similar relative scale to the atomic mass scale could be developed for gases using masses of equal volumes of gases as a base for comparison.
		of a substance is equivalent in mass to the relative atomic mass or relative molecular mass in grams.
		is the mass of one mole of a substance.
	www.launc.tased.edu.au /online/sciences/PhysSci/pschem/reactqty/RMM.htm (313 words)

	The Influence of Laser Energy and Matrix of MALDI on the Molecular Mass Distribution of Poly(ethylene glycol)
		The Influence of Laser Energy and Matrix of MALDI on the Molecular Mass Distribution of Poly(ethylene glycol)
		But the characterization of synthetic polymers by MALDI-TOF-MS has yielded inconsistent results, indicating that the MALDI-MS determined molecular mass distribution (MMD) is sensitive to instrumental and sample preparation parameters used to obtain the polymer mass spectrum.
		We considered the effects of laser energy and matrix on the molecular mass distribution of several polymers of varying stability.
	www.nist.gov /sigmaxi/Posters03/Wetzel-abst.html (265 words)

	Scripps Center for Mass Spectrometry - What is Mass Spectrometry?
		A mass spectrometer determines the mass of a molecule by measuring the mass-to-charge ratio (m/z) of its ion.
		The average mass of a molecule is calculated using the weighted average mass of all isotopes of each constituent element of the molecule.
		Tandem mass analysis in space is performed by consecutive analyzers whereas tandem mass analysis in time is performed with the same analyzer, which isolates the ion of interest, fragments it, and analyzes the fragment ions.
	masspec.scripps.edu /MSHistory/whatisms.php (12923 words)

	Mauritz - MALDI-TOF Mass Spectrometry
		Due to the low molar mass of the polymer, the molar mass distribution is easily derived as 58 g/mol from the peak-to-peak mass increments.
		At m/z 23000, the mass resolution is not sufficient to resolve adjacent oligomer molecular ions with a difference of 44 mass units.
		This spectra has a continuous distribution due to convolution of the molecular ions, however, the molar mass for individual oligomers is apparent, as shown in the insert, with a peak-to-peak mass resolution of 104 g/mol.
	www.psrc.usm.edu /mauritz/maldi.html (2520 words)

	mass spectra - the molecular ion (M+) peak
		In the mass spectrum, the heaviest ion (the one with the greatest m/z value) is likely to be the molecular ion.
		The presence of a chlorine atom in a compound causes two peaks in the molecular ion region - the M+ peak and the M+2 peak depending on whether the particular molecular ion contains a chlorine-35 or chlorine-37 isotope.
		The carbon value is 12.0000, of course, because all the other masses are measured on the carbon-12 scale which is based on the carbon-12 isotope having a mass of exactly 12.
	www.chemguide.co.uk /analysis/masspec/mplus.html (904 words)

	Mass Spec Services
		For mass spectral analysis of peptides and proteins, the sample must be soluble in dilute acid and it is recommended the sample undergo at least one round of hplc.
		In the case where the protein sequence is known, the peptide molecular weights obtained are sufficient to identify the sequences that are phosphorylated.
		Mass analysis indicated that this was a phosphatidylinositol phospholipid with C18:0 and C20:4 fatty acyl chains running at m/z 283 and m/z 303, respectively.
	www.pitt.edu /~rsup/massServices.html (1225 words)

	#1 Site For Learning Chemistry
		In all chemical reactions, masses of atoms or molecules have to be considered.
		Atomic mass of O is 16, gram atomic mass of O is 16 gm.
		Molecular mass of water is 18, gram molecular mass of water is 18 gm.
	home.att.net /~cat6a/chem_reac-V.htm (837 words)

Try your search on: Qwika (all wikis)