Molecular weight multiple value

The latter value is about half of the former thus if we combine the two, we obtain a minimum of 16 500 g mol for the molecular weight. This value would correspond to one atom of iron and two atoms of sulfur per molecule. Of course the true molecular weight may be any integral multiple of sr 16 500. 

Strictly speaking, the terms molar mass and molecular weight refer to different quantities. Molar mass is the mass of one mole of polymer molecules and measured in g/mol, whereas molecular weight is dimensionless and refers to the weight (mass) of a single polymer molecule measured as multiples of the atomic mass unit u. The numerical values of both quantities are identical. Usually, no such strict distinction is made in the literature, and also in this contribution both terms will be used as synonyms for the strict term molar mass. 

For some compounds in the Wilschut database more than one permeability coefficient was gathered from literature. In some cases, the differences in kp were greater than one log unit underlining the interlaboratory variations of such measurements. For the development of a new QSPR model one may now either choose one representative data point for each molecule or combine the multiple data points in a reasonable way. In some cases authors even employed all the available data for a single compound. Apart from the permeability data, the data on the partition coefficient and even on the molecular weight may vary from one report to another. Differences in the partition coefficient are easily explained Some collections list experimentally determined values which depend on the experimental procedure employed... 

Because of the high numerical value of the argument M it is allowed to replace the summation (step function) by an integration (smooth curve), despite the discrete nature of the values of AM which are equal to the integer multiple of the molecular weight of the repeating unit, Mq, in the case of homopolymers ... 

By means of equations (30) and (36) it is possible to calculate the number of aromatic rings per average molecule of mineral oil fractions with Ra < 1 and Ra > 1, respectively, from the molecular weights and the percentages of carbon atoms in aromatic structure. The calculated values are not exact values since it is assumed that the multiple ring systems are kata-condensed however, this often seems to be the case. 

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