Ramsay

Ramsay-Shields equation An equation relating the molecular surface energy of a liquid with its temperature... 

Gr. helios, the sun). Janssen obtained the first evidence of helium during the solar eclipse of 1868 when he detected a new line in the solar spectrum. Lockyer and Frankland suggested the name helium for the new element. In 1895 Ramsay discovered helium in the uranium mineral clevite while it was independently discovered in cleveite by the Swedish chemists Cleve and Langlet at about the same time. Rutherford and Royds in 1907 demonstrated that alpha particles are helium nuclei. 

Gr. neos, new) Discovered by Ramsay and Travers in 1898. Neon is a rare gaseous element present in the atmosphere to the extent of 1 part in 65,000 of air. It is obtained by liquefaction of air and separated from the other gases by fractional dishhation. 

Gr. argos, inactive) Its presence in air was suspected by Cavendish in 1785, discovered by Lord Rayleigh and Sir William Ramsay in 1894. 

Gr. xenon, stranger) Discovered by Ramsay and Travers in 1898 in the residue left after evaporating liquid air components. Xenon is a member of the so-called noble or "inert" gases. It is present in the atmosphere to the extent of about one part in twenty million. Xenon is present in the Martian atmosphere to the extent of 0.08 ppm. the element is found in the gases evolved from certain mineral springs, and is commercially obtained by extraction from liquid air. 

From radium called niton at first, L. nitens, shining) The element was discovered in 1900 by Dorn, who called it radium emanation. In 1908 Ramsay and Gray, who named it niton, isolated the element and determined its density, finding it to be the heaviest known gas. It is essentially inert and occupies the last place in the zero group of gases in the Periodic Table. Since 1923, it has been called radon. 

The evidence obtained in compaction experiments is of particular interest in the present context. Figure 3.22 shows the results obtained by Avery and Ramsay for the isotherms of nitrogen on compacts of silica powder. The hysteresis loop moved progressively to the left as the compacting pressure increased, but the lower closure point did not fall below a relative pressure of 0-40. Similar results were obtained in the compaction of zirconia powder both by Avery and Ramsay (cf. Fig. 4.5), and by Gregg and Langford, where the lower closure point moved down to 0-42-0-45p° but not below. With a mesoporous magnesia (prepared by thermal decomposition of the hydrated carbonate) the position of the closure point... 

Fig. 3.22 Adsorption isotherms of nitrogen at 77 K on silica powder and its compacts. (A) uncompressed (B) 10 ton in (C) 40 ton in" (D) 50 ton in (E) 100 ton in . Open symbols represent adsorption, solid symbols desorption. (Courtesy Ramsay.)...

Experimental findings in the intervening years have tended to support and extend this concept. The results obtained by Ramsay and Avery in their studies of the effect of compaction on the nitrogen isotherms of two finely divided powders, one of zirconia and the other of silica, are especially instructive in the present context. As in earlier studies (cf. Chapter 3) the isotherm on the original powder was of Type II, but on compaction it first became Type IV with a well defined hysteresis loop, which moved... 

Figure 7.1 7 Potential energy curves for the ground and several excited states of C2. (Reproduced, with permission, from Ballik, E. A. and Ramsay, D. A., Astrophys. J., 137, 84, 1963 published by the University of Chicago Press Copyright 1963 The American Astronomical Society)...

Handling and storage Ramsay and Young Tabulated (see also Vapour pressure and Distillation range)... 

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