This is because the mass is given per one mole. See more. Formula Mass: Formula mass is the sum of the masses of atoms present in the empirical formula. Molecular weight is a measure of the sum of the atomic weight values of the atoms in a molecule. In practice four averages are used, representing the weighted mean taken with the mole fraction, the weight fraction, and two other functions which can be related to measured quantities: . The polymers produced in polymerization … Thus larger the size of molecule more its contribution to the molecular weight average. Protein molecular weight markers, sometimes identified as protein standards or protein ladders, are used to estimate the molecular weight of proteins of interest, to monitor the progress of electrophoretic separation or transfer, and as a positive control for analysis conditions. gram-molecular weight, amount of a molecular substance whose weight, in grams, is numerically equal to the molecular weight molecular weight, weight of a molecule of a substance expressed in atomic mass units (amu). Molecular weight is used in chemistry to determine stoichiometry in chemical reactions and equations. relative molecular mass n the sum of all the relative atomic masses of the atoms in a molecule; the ratio of the average mass per molecule of a specified isotopic composition of a substance to one-twelfth the mass of an atom of carbon-12., (Symbol) Mr (Abbrev) r.m.m (Former name) molecular weight Sponsored Links . The mass of one mole of carbon 12 atoms is exactly 12 grams, which is its molar mass is exactly 12 grams per mole. Molecular Mass Definition . The definition of molecular weight is directly related to the carbon-12 isotope. 1. Definition of gram-molecular weight in the Definitions.net dictionary. Definition and molecular weight (molar mass) of some common substances . Information and translations of gram-molecular weight in the most comprehensive dictionary definitions resource on the web. The molecular weight of a particular polymer molecule is a product of the degree of polymerization and the molecular weight of the repeating unit. Effect of Molecular Weight 10 For example, let’s look at hydrocarbons Very short chain … A molecular weight marker is a molecule used to provide an estimate of the size of molecules subjected to gel electrophoresis.This is a technique in which DNA, RNA, or proteins are separated by size, using an electrical current on a gel.This term should not be confused with molecular markers in genetics — areas in which an organism’s DNA differs from the rest of the population and … ‘The ethyl group has a greater molecular weight than the smallest alkyl radical which is the methyl group.’ ‘Alcohols and ethers having higher molecular weights do not dissolve well in water, however, because the water molecules can not completely surround those molecules.’ The mass of one mole of carbon 12 atoms is exactly 12 grams, which is its molar mass is exactly 12 grams per mole. molecular weight to be calculated, the peak molecular weight Mp, defined as: Mp = molecular weight of the highest peak Therefore, Mp is the mode of the molecular weight distribution. The sum of the atomic weight's 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). The molecular mass gives the mass of a molecule relative to that of the 12 C atom, which is taken to have a mass of 12. The old symbol was amu, while the most correct symbol is u (a lower-case letter u). ‘The ethyl group has a greater molecular weight than the smallest alkyl radical which is the methyl group.’ ‘Alcohols and ethers having higher molecular weights do not dissolve well in water, however, because the water molecules can not completely surround those molecules.’ Molecular Mass Definition. The molecular mass gives the mass of a molecule relative to that of the 12 C atom, which is taken to have a mass of 12. n. The sum of the atomic weights of all the atoms in a molecule. The main difference between molar mass and molecular weight is that molar mass gives the mass of a mole of a particular substance whereas molecular weight is the mass of a molecule of a particular substance. Like the gram atomic weight, in the case of molecules, we describe the weight of one mole (6.022 x 10^23 molecules) as the gram molecular weight. Because virtually all polymers are mixtures of many large molecules, we have to resort to averages to describe polymer molecular weight. Molecular mass is a number equal to the sum of the atomic masses of the atoms in a molecule. Definition of average molecular weight c. z average molecular weight ( MZ ) M Z= NiMi (ultracentrifugation) 2 d. general equation of average molecular weight : M = ( a=0 , Mn … Meaning of gram-molecular weight. The highest molecular weight polymers are obtained under strictly controlled stoichiometric conditions, that is to say, an exact 1:1 molar ratio of two functional groups is necessary according to the classical theory of polycondensation. Two experimentally determined values are common: \(M_n\), the number average molecular weight, is calculated from the mole fraction distribution of different sized molecules in a sample, and \(M_w\), the weight average molecular weight, is calculated from the weight fraction distribution of different sized molecules. ¹ Source: wiktionary.com. Different average values can be defined, depending on the statistical method applied.