This work shows how the molecular weight of sodium alginate can be determined by measuring the values of the osmotic pressure, P, in the presence of low concentrations of sodium chloride, and extrapolation of P/C to C = 0, where C is the concentration of sodium alginate. For different samples of sodium alginate the slope of the curve P/C against C was independent of the molecular weight. Molecular weight values from 48,000 to 186,000 were obtained. The intrinsic viscosity of the different samples were linearly related to the degree of polymerization.
By FREDERICK GEORGE DONNAN and BRYCE CHUDLEIGH BURT. THE object of the experiments described in this paper was to examine the various solid phases which can separate from the two-component system, water-lithium nitrate, and t o determine the conditions of their existence in contact with the saturated solution. AS the first member of im group, lithium shows many analogies with the elements of the succeeding series, in particular with calcium. I n agreement with this, lithium nitrate is a very deliquescent and extremely soluble salt. It is also characterised by a tendency t o form supersaturated solutions, resembling calcium chloride in this respect. The first experiments on the hydrates of lithium nitrate appear to have been those of Kremers (Jahresberichte, 1854, 324; Pogg. Ann., 92, 520), who mentions t h a t he obtained a hydrate crystallising in needles and also another forni crystallising in rhombohedra which he assumed to be the anhydrous salt. The former he regvrded as the hydrate LiN0,,2$H20. The same formula was assigned to i t by Troost (Julwesberichte, 1857, 140). Both observers obtained this salt by crystallisation below 20' .
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.