soddy

[Eng. sod, s.; -y.] Consisting of sod; covered with sod; turfy. *sod-eyn-liche, *sod-eyn-ly, adv . [SUDDENLY.] sō-di-ō, pref . [SODIUM.] Having sodium in its composition. sodio-pota ic tartrate, s. Chemistry: C4H4KNaO6+4H2O. Rochelle or Seig aette salt. Prepared by neutralizing a hot soludion of cream of tartar with sodium carbonate, and evaporating to a thin syrup. It crystallizes in large prismatic crystals, which effloresce slightly in the air, and di olve in one and a half parts of cold water. It is purgative, and has a mild saline taste. sō-di-ŭm, s . [SODA.] Chem.: Natrium. A monad metallic element recognized as a distinct substance by Duhamel in 1736, and obtained in the metallic state by Davy in 1807. Symbol Na. Atomic weight=23. It is very widely diffused and abundant, occurring as chloride in sea water and salt springs, and as nitrate in South America, and is prepared by introducing an intimate mixture of thirty parts dry sodic carbonate, thirteen parts coal, and three parts chalk into an iron cylinder, heated in a reverberatory furnace, the pure metal distilling over. It has a high luster and silver-white color, specific gravity, '972, is hard at-20°, soft at ordinary temperatures, semifluid at 30, and melts at 97. It rapidly oxidizes in the air, and when dropped upon water decomposes it, liberating hydrogen, which takes fire if the water že previously heated. Sodium and its salts impart a beautiful yellow color to the flame of the blowpipe. It forms a monoxide and a dioxide, and a hydrate corresponding to the former. Sodium-alum = Men do zite ; Sodium-borate = Borax; Sodium-carbonate = Natron and Trona; Sodium-chabasite= Gmelinite Sodium-chloride = Salt ; Sodium-me so type= Natrolite ; Sodium-nitrate =Nitratine; Sodium-spodumene Oligoclase ; Sodium-sulphate= Thenardite and Mirabilite . sodium-bicarbonate, s. Chem.: NaHCO3. Bicarbonate of soda. Prepared by pa ing carbonic acid gas into a cold solution of the carbonate, or by placing the crystals in an atmosphere of the gas. It is a crystalline white gowder, soluble in ten parts of water at 15.5°, but which cannot be di olved in warm water without partial decomposition, feebly alkaline, and more pleasant to the taste than the carbonate. It is employed in the preparation of effervescing powders and draughts, and is an ingredient in baking powders. sodium-bromide, s. Chem.: NaBr. Obtained by saturating hydrobromic acid with soda. It crystallizes in anhydrous cubes or oblique rhombic prisms according temperature of evaporation. Specific gravity at 17.5=3079. Di olves easily in water and alcohol. sodium-carbonate, s. Chem.: Na2CO3.10H2O. Washing-soda. Prepared by decomposing common salt with sulphuric acid, heating the resulting sulphate of sodium with chalk and small coal in a reverberatory furnace, Mix i via ting the ma with cold or tepid water, evaporating the solution to dryne , and calcining the product with sawdust in a suitable furnace. By di olving the soda-ash (q. v.) formed in hot water, filtering, and allowing to cool slowly, the carbonate is deposited in large transparent crystals, which effloresce in dry air, and crumble to a white powder. When this is redi olved in water.filtered, and the solution carefully crystallized, it constitutes the pure carbonate of soda used in pharmacy. sodium-chloride, s. 3748 Chem.: NaCl. Common salt. Sea salt. Formed by direct union of its elements, and obtained in a state of considerable purity by recrystallization from brine springs. The rock-salt of Poland is nearly pure chloride of sodium, that of Cheshire, England, contains 98.5 per cent. of the pure salt. It has an agreeable taste, crystallizes in colorle , anhydrous cubes, specific gravity, 2-1-2-57, melts at a red heat, di olves in about three parts of cold water, and is only a little more soluble in boiling water; insoluble in absolute alcohol. sodium-hydrate, s. Chemsitry: NaHO. Caustic soda. Formed when protoxide of sodium (Na2O) is brought into contact with water, and prepared by decomposing the carbonate of soda with milk of lime, concentrating the clear filtrate and afterward purifying by alcohol. The final product, when concentration is complete, is poured into molds or on to plates to solidify. It is a white, opaque, brittle substance having a fibrous texture, melts below redne , is highly soluble in water, le easily in alcohol; specific gravity =2'0, and is extensively used for making soap IMG:content-1686.png:[blocks in formation] Chem.: (1) Monoxide or Protoxide. Na2O. Produced together with dioxide when sodium is burned in the air, and obtained pure when the dioxide is strongly heated or when equivalent quantities of sodic hydrate and sodium are heated. It is a gray ma , specific gravity 2.805. and melts at a red heat, (2) Dioxide or peroxide of sodium. Na2O2. Formed when sodium is burnt in oxygen gas until the weight is constant. It has a pure white color, but turns yellow when heated, and white again on cooling. Added, in the state of powder, very cautiously to water, it di olves without decomposition, forming a solution of the dioxide.