Topic
Vapours
About: Vapours is a research topic. Over the lifetime, 1153 publications have been published within this topic receiving 15022 citations.
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95 citations
95 citations
TL;DR: In this paper, the second virial coefficients of a num ber of organic vapours have been measured at pressures up to 1 atm. and temperatures ranging from 40 to 130°C.
Abstract: The compressibilities of a num ber of organic vapours have been measured at pressures up to 1 atm. and temperatures ranging from 40 to 130° C. The observed second virial coefficients are compared with values calculated from the critical data by the Berthelot equation. The results show two distinct classes of behaviour. Class I is shown by ethane, ethylene, n -hexane, cyclohexane, benzene, diethyl ether, ethyl chloride, chloroform and carbon tetrachloride, where the measured second virial coefficients are in agreement with the calculated values. Class II by acetaldehyde, acetone, acetonitrile, methyl alcohol, where the measured second virial coefficients are consistently very much higher than the calculated values. It is concluded that the vapours of polar substances for which the energy of attraction between molecules, due to dipole interaction or to hydrogen bonding, is larger than kT undergo dim erization. This view is supported by thermal conductivity data. The range of validity of the Berthelot equation for both non-polar and polar vapours is examined.
93 citations
TL;DR: In this paper, a back-propagation technique was used to train an artificial neural network, based on a back propagation technique, to recognize simple vapours (water, proano, ethyl acetate and acetone).
Abstract: Organic thin-film sensors bases on the thermal evaporation and dip-coating of polyaniline, and on the Langmuir-Blodgett deposition of a vanadium porphyrin, have been fabricated. The d.c. electrical resistance of the individual elements are found to exhibit different changes on exposure to simple vapours (water, proano, ethyl acetate and acetone). These data have been used successfully to train an artificial neural network, based on a back-propagation technique, to recognized two of the vapours.
87 citations
TL;DR: In this article, the results for the adsorption of benzene, toluene and n-heptane vapours on mercury have been obtained and the films were found to be gaseous and obeyed the Volmer equation F(A-b) = kT, where F = spreading pressure, A = area per molecule and b = co-area.
Abstract: Reversible results for the adsorption of benzene, toluene and n-heptane vapours on mercury have been obtained. The films were found to be gaseous and obeyed the Volmer equation F(A-b) = kT, where F = spreading pressure, A = area per molecule and b = co-area. The possibility that the films might be immobile was considered and the Langmuir equation was applied but found unsatisfactory. A standard state for the surface phase was defined and the free energy, total energy and entropy of adsorption evaluated. The heat of adsorption was shown to increase with the amount on the surface. A number of phase changes were found to occur after the completion of monolayer adsorption, the most striking being interpreted as the change over from 'flat' to 'vertical' adsorption of the toluene molecules. Others were thought to be either two-dimensional condensation or adsorption of a second layer.
87 citations