By completing this lesson, you should be able to: â¢ Identify the funding policy (annual, incremental, or full) that applies to each of the. five major appropriation categories of interest to the defense acquisition community. (RDT&E, Procurement, O&M, MILCON, and MILPERS).
Silicon dioxide (SiO 2), silicon's most common compound, is the most abundant compound in the earth's crust. It commonly takes the form of ordinary sand, but also exists as quartz, rock crystal, amethyst, agate, flint, jasper and opal. Silicon dioxide is extensively used in the manufacture of glass and bricks. Silica gel, a colloidal form of silicon dioxide, easily absorbs moisture and is used as a desiccant. Silicon forms other useful compounds.
Reaction with water. Silicon dioxide doesn't react with water, because of the difficulty of breaking up the giant covalent structure. Reaction with bases. Silicon dioxide reacts with sodium hydroxide solution, but only if it is hot and concentrated. A colourless solution of sodium silicate is formed.