Ammonia atmospheric composition

From the atmospheric composition we can infer the internal composition of a satellite. The temperature inside Titan probably reached values higher than 800 K or even higher than 1000 K, since the process of the chemical dissociation of ammonia was completely finished on this satellite and its atmosphere contains only molecular nitrogen (Dorofeeva and Ruskol, 2010 [109]). 

Macroporous open-cell nickel foam substrate was manufactured by the nickel electroplating of the polyurethane foam samples (cell density 60 ppi) followed by sintering in the dissociated ammonia atmosphere at 1100°C for 1 h. The foam samples were then deformed by a imiaxial compression to 1 mm thickness modifying the cell morphology and decreasing porosity from 95.5 % to 60-80 %. Deformed foams were subjected to the pack aluminizing and then annealed at 1000 C for 1 h under air to form a thin a-aliunina layer over the foam cell walls/ribs for a better adhesion of composite layers. 

The composition of the planetary atmospheres is fairly constant. This is indeed surprising in view of the fact that molecules such as methane, ammonia, and carbon dioxide are easily decomposed by the ultraviolet radiation from the sun. Presumably other reactions regenerate those substances that are light sensitive. 

The catalytic tests were carried out in a fixed bed micro-reactor at atmospheric pressure at 540 °C. The feed composition was 2.5 vol.% of propane, 5 vol. % of ammonia and 5 vol.% of oxygen. The weight of catalyst in the reactor was varied in order to keep the number of Fe ions in the reactor constant (9 pmol of Fe atoms). Conversion, selectivity and yields were calculated on the basis of mass balance in dependence on the time of stream. 

The vapor pressure of H2S04 above solutions with water depends on the solution composition and the temperature. For example, the vapor pressure at 25°C varies from 2.6 X 10-9 Pa for a 54.1 wt% H2S04-H20 solution to 5.9 X 10 6 Pa for a 76.0 wt% solution (Marti et al., 1997). The vapor pressures above solutions partially neutralized with ammonia are also reported by Marti et al. (1997) as discussed in Chapter 9.B.1, the vapor pressures of the partially neutralized solutions are orders of magnitude smaller than those of the acid. As a result, ammonia may play an important role in nucleation of gaseous sulfuric acid in the atmosphere to form new particles. 

Tetrammino-magnesium Chloride, [Mg(NH3)4]Cl2.—This compound is produced when magnesium chloride is volatilised in a stream of ammonia gas the ammine condenses as a white meal of composition MgCl2.lNH3. It decomposes quickly with loss of ammonia if exposed to air, but is capable of sublimation in an atmosphere of ammonia. 

If well-dried ammonia gas is passed over freshly sublimed aluminium chloride ammonia is rapidly absorbed, heat is developed, and the whole mass fuses and then gradually solidities as more ammonia is absorbed, leaving a white voluminous powder of composition A1C13.GNH3 or [A1(NH3)6]C13. Hexammino-aluminium chloride is stable at ordinary temperature and is much less hygroscopic than the chloride. It is decomposed by water with formation of aluminium hydroxide, and when heated in dry air is oxidised, yielding the oxide and ammonium chloride. If heated in an atmosphere of dry hydrogen it loses ammonia and passes into diammino-aluminium chloride, [A1(NH3)2]C13.5 Triammino-aluminium chloride obtained in this way by Persoz was not found by Stillmann and Yoder. 

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