Gram-molecular weight definition

The expression (2-4) provides the definition of a partial molal quantity if the gram-molecular weight (mole) is the unit of mass and of a partial specific quantity if the gram is the unit of mass. In the future, the symbol i will denote a partial molal quantity defined by the relation... 

Suppose we have a sample of polymer of weight w grams containing Nq molecules. By definition, the number average molecular weight is given by... 

Here ),p, the specific viscosity, is equal to the relative viscosity minus one. Staudinger designates C as the concentration of the solution in basal moles or the number of moles of the polymeric repeating unit per liter thus, for a starch acetate, it is the number of grams per liter divided by 288. K , is a constant particular to a definite series of homologues measured in a definite solvent, and M is the molecular weight. Ordinarily, this equation is employed for viscosity values extrapolated to zero concentration. Although the relationship is by no means exact " ... 

The K parameter in Equation 12.7 is related, by definition [20], to the molar stiffness function (also called the molar limiting viscosity number function) K and the molecular weight M per repeat unit (Equation 12.9), so that Equation 12.7 can be rewritten as Equation 12.10. If units of cc/gram are used for [r ] , then K is in units of grams°-25 cm1-5/mole0-75. 

A word of caution involves the definition of mole. As indicated above, SI moles are gram moles, the mass in grams of 6.02 x 10 molecules. There is an inconsistency in the SI system of units that may cause problems when converting molar densities and molar flow rates to mass densities and mass flow rates. A point in the system with molar concentrations (i.e., molar densities) of a and b has a mass density of p = qMa + bMs, where Ma and Mb are the molecular weights of the two components. 

The mole (abbreviated mol) is defined as the amount of a substance comprising as many elementary units as there are atoms in 12 g of The definition of the mole is equivalent to the statement that the mass of one mole of a pure substance in grams is numerically equal to its molecular weight calculated from the standard table of atomic weights, in which the atomic weight of carbon is given as 12.01115. This number differs from 12 because it applies to the natural isotopic mixture of carbon rather than to pure... 

The specification of molecular weight of the protein, in the definition of the protein component, is largely a matter of convenience. What is essential is that the mass and chemical nature of the protein component (or components) added to the system should be definitely specified. The value of Z2 must, of course, always be expressed so that it is stoichio-metrically correct the mean number of protons bound to, or removed from, the isoionic protein, -per gram protein, must obviously depend only on the stoichiometric composition of the system, not on the assumed molecularweight. For instance, Edsall, Edelhoch, Lontie and Morrison (1950) assumed the value of 69,000 for the molecular weight of their serum albumin preparations. The value of Z2 which they employed, therefore, represented the mols of H+ ion bound or removed, per gram protein, multiplied by the factor 69,000. 

Saponification value is a measure of the molecular weights of the triacylglycerides in coconut oils. The triacylglycerides with high value of saponification value are considered to make better quality soaps than those with low saponification value. As definition, saponification value is the number of milligrams of potassium hydroxide required to saponify completely the fatty material present and also to neutralize the free fatty acids present in one gram of the coconut oil. 

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