Inorganic Chemistry; With the Elements of Physical and Theoretical Chemistry

Book may have numerous typos, missing text, images, or index. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. 1908. Not illustrated. Excerpt: ... Part ni. PHYSICAL CHEMISTRY. CHAPTER IX. 8TATE8 OP MATTER. SOLIDS. . Form and Structure of Solids.--Solids may be homogeneous or heterogeneous. They are homogeneous when they contain only one kind of matter; heterogeneous when they consist of a mixture of two or more kinds of matter. Calcite and quartz are homogeneous; granite and the animal body are heterogeneous. Solids may be amorphous or crystalline. Amorphous solids are those which have no definite form, such as chalk, limestone, flint. A crystalline solid is one which is composed of crystals. A crystal is a solid bounded by straight lines and plane surfaces so arranged as to make a definite geometric form. Calcite and quartz occur in crystals; marble and granite are crystalline. Amorphous substances are usually opaque. . Crystals are mostly transparent, translucent, or white. Some are colored, but in many cases the color is due to impurities or to water of crystallization. Crystallization.--When a solution is evaporated the solid separates and usually in crystals. The form and size of the crystals depend upon the nature of the substance and the rapidity of the evaporation. Some solids become crystalline on cooling from fusion; some vapors condense to crystalline solids without passing through the liquid state; and some metals when displaced by chemical action or electrolysis separate in crystals. Illustrations.--Make a hot saturated solution of common alum and note the fine octahedral crystals which form as it cools. Melt sulfur in a clay crucible, let cool until a crust is formed on the surface, break the crust and pour out the liquid, and note the crystals which have formed. Place a few crystals of iodin in a flask or tube, heat until the vessel is full of the purple vapor: crystals form on the cool wall of ...