Weight average molecular weight (M w) measuring system includes the mass of individual chains, which contributes to the overall molecular weight of the polymer. Molecular weight is commonly abbreviated by M.W. molecular weight meaning: 1. another term for relative molecular mass specialized 2. another term for relative molecular mass…. This is because the mass is given per one mole. It is based on the fact that bigger molecules contain more mass than smaller molecules. Definition of molar mass averages. Also called relative molecular mass . Although the definition and units are different for molar mass and molecular weight, the value is the same. 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 The definition of molecular weight is most authoritatively synonymous with molecular mass; however, in common practice, it is also highly variable as are the units used in conjunction with it. The old symbol was amu, while the most correct symbol is u (a lower-case letter u). The molecular weight of a polymer is a way of describing how long the polymer chains are Each monomer has a molecular weight (often called the formula weight) Adding the monomers together to make polymers increases the molecular weight The longer the chains, the higher the molecular weight . A good example is molecular mass or molecular weight. Atomic weight is a common name for relative atomic mass, which is defined as the ratio of the average mass of one atom of an element to 1 12 \frac{1}{12} 1 2 1 of the mass of an atom of carbon-12. ¹ Source: wiktionary.com. 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. Molecular Mass Definition. The average atomic mass is measured in the unified mass unit (u). 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. Molecular mass is a number equal to the sum of the atomic masses of the atoms in a molecule. Meaning of gram-molecular weight. ‘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.’ 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. In the SI system the unit of M is [kg/kmol] and in the English system the unit is [lb/lbmol], while in the cgs system the unit of M is [g/mol]. Unlike pure compounds, polymers form as a mixture of different molecules (pure compounds contain … For instance a particular polythylene molecule with $$DP = 1000$$ will have a molecular weight of 28,000. Since larger molecules in a sample … 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). Molecular weight is either unitless or expressed in terms of atomic mass units (amu) or Daltons (Da). An atomic mass unit is described as 1/12 th the weight of the carbon-12 isotope. Different average values can be defined, depending on the statistical method applied. 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 definition, of or relating to or caused by molecules: molecular structure. History. The unified mass unit is related to the molar mass constant (M … The weight in atomic mass units of each of the atoms in a given formula is the molecular weight of a substance. 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. or MW. ‘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.’ 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 … These are defined below. Often, the terms are called weight rather than mass and used interchangeably. Definition of gram-molecular weight in the Definitions.net dictionary. Effect of Molecular Weight 10 For example, let’s look at hydrocarbons Very short chain … The key difference between number average and weight average molecular weight is that the number average molecular weight refers to the mole fraction of molecules in a polymer sample whereas the weight average molecular weight is the weight fraction of molecules in a polymer sample.. Define molecular weight ratio. 1. What does gram-molecular weight mean? Molar Mass: Molecular Weight: Definition: It is the mass of a mole of a particular substance: It is the mass of a molecule: Unit: Kgmol-1: Atomic mass units: Calculation: It is calculated by dividing the mass of a substance by the amount of the substance: It is calculated as the mass of substance relative to the 1/12 th of the mass of the carbon-12 atom. 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 A molecular weight is simply the weight of one mole (6.022x10^23 molecules) of a compound. Search molecular weight and thousands of other words in English definition and synonym dictionary from Reverso. 2.4.2 Weight Average Molecular Weight. 1. 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