Ampere Boiling

Ammonia a base, 184 boiling point, 64 complexes, 392, 395, 408 complex with Ag+, 154 Haber process for, 150 and hydrogen chloride, 24 model of, 21 molar volume. 60, 64 production, 150 P V behavior of, 19, 51, 60 solubility, 20 Ampere, 241 Amphoteric, 371 complexes, 396 Analogy... 

Kf = molal freezing-point depression constant Kt,= molal boiling-point elevation constant A = absorbance a= molar absorptivity b = path length c= concentration Q = reaction quotient /= current (amperes) q= charge (coulombs) f= time (seconds)... 

The electrodes are connected to a suitable variable source of direct current (Note 6), the magnetic stirrer is started, and a potential of about 50 volts is applied. This results in a current flow of 1-2 amperes. The solution soon comes to boiling the voltage is then regulated so that a rapid reflux is maintained (Note 7). 

The mixture is first warmed to 75°, and the high current keeps it boiling. Alcohol may be added from time to time to replace that evaporated. The current density is 15 amperes, and the E.M.E. 7—8 volts. After about 20 ampere hours have passed, the current density is cut down to 2 amperes. After 24 ampere hours have passed, the current is stopped the hot cathode liquid is then poured into a mixture of 50 c.cs. of sulphuric acid and 100 c.cs. of water, and allowed to stand. The p-phenylene-diamine sulphate is filtered and dried on a porous plate. 

Moissan succeeded in volatilising iron in his electric furnace with a current of 350 amperes at 70 volts. In a few minutes a sublimate or distillate of iron was obtained on a water-cooled tube 4 as a grey powder mixed with some brilliant and malleable scales, and possessed of the same chemical properties as the finely divided metal. The distillation of iron in this manner is difficult on account of the violent frothing caused by the boiling metal evolving occluded gases.5... 

Lead triethyl, EtsPb.-Sixty-five grams of lead triethyl chloride, covered with 100 c.c. of distilled water, are treated with 40 c.c. of 5-Normal sodium hydroxide and the mixture stirred until solution is complete. Addition of 200 c.c. of 5-Normal sodium hydroxide precipitates the lead triethyl hydroxide, which is separated. Sixty grams of the latter in 200 c.c. of 95 per cent, alcohol are electrolysed with lead electrodes, using a current density of 0-01 amperes per sq. cm. Lead triethyl forms as an oil at the cathode. It is pale yellow in colour, density 1 94, and readily oxidised in air, giving a yellowish powder. It may be distilled in steam, and at 2 mm. pressure it boils at 100° C., but it decomposes when distilled at ordinary pressure. It is still liquid at C. In dilute solution it corresponds to the simple formula,... 

A solution of 150 g. of strychnine in 900 g. of sulfuric acid and 600 cc. of water is distributed equally between the cathode chambers of six cells (194) connected in series. A current of 5 amperes is passed through the solution for 16 hours and the temperature maintained at 12°. The solution is diluted with ice, filtered, and made alkaline with a large excess of concentrated sodium hydroxide solution. The granular precipitate, after washing and drying, is extracted with 800 cc. of boiling ethanol. The residue (54 g., m.p. 183-185°), after removal of the solvent, is fractionally crystallized from benzene and jdelds 36 g. of tetrahydrostrychnine (m.p. 202°) and then 17 g. of strychnidine melting at 244—245°. 

Among numerous problems of cryogenic engineering there is the one of electrical conduction from an external room temperature source into a low temperature environment. For currents over a few amperes the problem is one of providing electrical conductors of suitable current carrying capacity without introducing excessive thermal conduction. In working at temperatures of liquid helium, the thermal losses quickly result in substantial boil-off. To conduct currents of several hundred amperes would appear totally impractical. 

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