The Hydrous Oxides |
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acetate action adsorbed adsorbed water adsorption adsorption capacity agglomeration alkali alum alumina aluminum sulfate ammonia ammonium amount anhydrous anorg Bemmelen blue boiling calcium carbon cement cent Chem chim chromic oxide coagulation cobalt colloidal colloidal solution color composition compound Compt containing crystalline crystals cubic centimeters cupric oxide curves definite dialysis dialyzed dilute dioxide electrolytes excess ferric chloride ferric oxide formation formed FREUNDLICH gelatinous gelatinous oxide gelatinous precipitate giving grams heating hydrate hydrochloric acid hydrolysis hydrous alumina hydrous chromic oxide hydrous ferric oxide hydrous oxide hydrous stannic oxide hydroxide Ibid increase insoluble jelly Kolloid-Z Kolloidchem latter Liebig's Ann mixture mols mordant neutral nitrate observations obtained oxalate oxide sol pentoxide peptized peroxide pH value Phys physik potassium prakt precipitation precipitation value prepared presence readily rend silica sodium soil soluble stabilizing sulfide sulfuric acid tannin temperature thorium tion trioxide washing WEISER wool yellow
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Page 343 - This may be due to one or more of the following causes: (1) The point of view of the writers.
Page 14 - A cluster or network of such needle-shaped flexible crystals which adsorb water strongly would form a viscous or plastic mass which is usually known as a gelatinous precipitate. If the crystals are compact and rigid rather than thin and flexible, they would not form a gelatinous precipitate unless they united into threads or strings that would possess the flexibility and elasticity which characterize a thin needle crystal. Obviously, the particles need not be crystalline and, as a rule, they probably...
Page 9 - Weimarn9 concludes from his investigations that a jelly is a sponge composed of highly dispersed, crystalline granules soaked in dispersive medium. While Bradford, Moeller, and von Weimarn may have sufficient evidence to convince them...
Page 205 - ... temperature-composition curves of acetonedried preparations. Such evidence is altogether inconclusive, particularly when the nature and location of the " flats " in the curves are determined almost exclusively by the history of the sample. The same may be said of the " flats " in the vapour pressure curves of van Bemmelen. The adsorptive capacity of a hydrous oxide for water at different stages of dehydration is determined by the physical character of the preparation ; hence a
Page 205 - ... medium, Sn(OH)4 was supposed to go over into other less basic members of the series. Thus by suitable conditions of precipitation and drying with acetone at 0° to 10°, orthodistannic acid was supposedly formed ; at 35° to 46°, orthotristannic acid ; and so on. Different so-called j3-stannic acids were likewise prepared and many of them assigned formulas. As proof of hydrate formation, Willstatter cites the regions of almost constant water content in the temperature-composition curves of acetonedried...
Page 22 - At relatively high concentrations of neutral salts, the specific effect of cations other than hydrogen and of anions other than hydroxyl would doubtless appear.
Page 364 - By shaking hydrous copper oxide with varying concentrations of an ether solution of eosin, a typical adsorption isotherm is obtained, showing no evidence of compound formation. The maximum amount of eosin adsorbed under these conditions is only about one-tenth of that necessary to form copper eosinate. Starting with colloidal hydrous copper oxide and colloidal eosin acid, lakes were obtained varying in composition between 2 molecules of copper to 1 of eosin and 2 molecules of eosin to 1 of copper....
Page 26 - Factors that influence the formation of jellies in general are: A jelly may be expected to form if a suitable amount of a highly hydrous substance is gotten into colloidal solution and allowed to precipitate at a suitable rate without stirring. If the concentration of the hydrous substance is too low, no jelly or only a very soft jelly can result. If the precipitation from colloidal solution is too rapid, contraction is likely to occur with the formation of a gelatinous precipitate instead of a jelly;...
Page 205 - Willstatter and his collaborators3 adopted the older view that the behavior of the variety of oxides could be explained best by assuming the existence of more or less stable hydrates. Willstatter claimed to remove all the adsorbed water from a compound by drying rapidly in vacuum or by leaching with acetone. The composition of a gel formed in a special way and dried by the acetone method at —35° to +10° was represented by the formula Sn(OH)4 • H2O; but when dried at room temperature the analysis...
Page 177 - Anderson1 explained the hysteresis from the known fact that a liquid in a capillary tube has a greater vapor pressure when being filled than when being emptied, as in the former there is a diminution of the curvature of the liquid meniscus, due to incomplete wetting.