A comprehensive treatise on inorganic and theoretical chemistry Volume 1 - Joseph William Mellor, Paperback

• Release Date   6/27/2012
• ISBN-13   9781236543790 | 978-1-236-54379-0
• ISBN   1236543793 | 1-236-54379-3
• Format   Paperback
• Author(s)   Joseph William Mellor
• This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1922 edition. Excerpt: ...the anhydrous sulphate or the decahydrate. When in equilibrium, the solution in contact with the solid will contain the amounts of sodium sulphate--Na2S04--indicated by the solubility curves, Fig. 2. The saturated solutions, when in equilibrium, have the same concentration and are identical in every way. We cannot continue the observation of the solubility of the decahydrate beyond 32383, because it immediately splits up either into a less hydrated form--e.g. Na2S04.7H20--or the anhydrous form, Na2S04. The solubility curve of the heptahydrate meets the solubility curve of the anhydrous sulphate in the region of instability. transition point from the heptahydrate to the anhydrous salt is 34, or Na2S04.7H2ONa2S04+7H20 The so-called eutectic points E and Ez will be discussed later, but since the transformation of the anhydrous salt into the hydrate takes an appreciable time, it is possible to measure the approximate solubility of the anhydrous salt below 328. This is indicated by the dotted line in the diagram. In saturated solutions of hydrates, a definite hydrate is in dynamic equilibrium with the solution. if the hydrate changes as shown by E. Demarcay's study (1883) of the hydrates of thorium sulphate, the maximum amount of a salt which can enter into solution depends on its temperature and on its state of hydration. the solubilities of the different hydrates of a salt are different, and at the transition temperature, there is a break in the continuity of the solubility curve. H. W. B. Roozeboom's studies of the hydrates of a number of salts show that the solubility curves of the different hydrates of a salt indicate the limits of their stability. The solubilities of the two sodium sulphates--anhydrous and decahydrate--are quite different. If...