Author : Mohammed Reza Arshadi
Publisher :
ISBN 13 :
Total Pages : 0 pages
Book Rating : 4.:/5 (144 download)
Book Synopsis Mass Spectrometric Investigation of Gas Phase Hydration Equilibria Involving (a) Hydration of the Halide Negative Ions, (b) Hydration of the Hydroxide, Nitrogen Dioxide and Oxygen Negative Ions, (c) Hydration of the Proton by : Mohammed Reza Arshadi
Download or read book Mass Spectrometric Investigation of Gas Phase Hydration Equilibria Involving (a) Hydration of the Halide Negative Ions, (b) Hydration of the Hydroxide, Nitrogen Dioxide and Oxygen Negative Ions, (c) Hydration of the Proton written by Mohammed Reza Arshadi and published by . This book was released on 1969 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The gas phase hydration of the halide negative ions was studied by means of a specially designed mass spectrometer which is capable of operating at an ion source pressure as high as 10 torr. By the determination of the equilibrium constants for the general reaction (1). (1) X[superscript -] (H[subscript 2]0)[subscript n-l] + H[subscript 2]0 [symbols] X[superscript -](H[subscript 2]0)[subscript n] at various temperatures the thermodynamic values of [delta]H°[subscript n-1], [delta]G°[subscript n-1, n] and [delta]S°[subscript n-1, n] were determined. The values of n, the number of water molecules around the negative ion, ranged from 1 to 5 for F[superscript -]; 1 to 4 for Cl[superscript -] and Br[superscript -]; and 1 to 3 for I[superscript -]. In addition to the halide negative ions, the gas phase hydration of O[superscript -][subscript 2], 0D[superscript -] and NO[superscript -][subscript 2] was also studied. The [delta]H [subscript n-1,n],[delta]G°[subscript n-1,n], [delta]S°[subscript n-1, n] were determined for 0D[superscript -] with n=1 to n=5 and for 0[superscript -][subscript 2] with n=1 to n=3. However, the study of the N0[superscript -][subscript 2](H[subscript 2]0)[subscript n] was carried out at only one temperature (292°K), therefore, only [delta]G°[subscript n-1, n292] with n from 2 to 4 could be calculated. A theoretical calculation of the potential energies of cluster X[superscript -](H[subscript 2]0)[subscript n] is presented. This calculation was based on the various electrostatic energies involved between the central ion and the ligand molecules as well as those among the ligand molecules. A qualitative agreement was observed between the potential energies [delta] E[subscript n-1,n] calculated and AH°[subscript n-1,n] obtained experimentally. The entropy values, [delta]S[subscript 0, 1] for reaction (1) were calculated theoretically and are compared with the experimental values. From the results of this work and the study of the gas phase hydration energies carried out by other workers in this laboratory, a comparison is made between the hydration of the positive and negative ions. Our studies indicate that the initial hydration steps are more favorable for positive ions. However, as more water molecules are added to the clusters, negative ion hydration becomes more favorable. The trend in our data supports the single ion hydration energies obtained from the Randles free energies of hydration.
