Question & Answers 1. Define the term ‘amorphous’. Give a few examples of amorphous solids. Sol. Amorphous solids are those substances, in which there is no regular arrangement of its constituent particles, (i.e., ions, atoms or molecules). The arrangement of the constituting particles has only short-range order, i.e., a regular and periodically repeating pattern is observed over short distances only, e.g., glass, rubber, and plastics. 2. What makes glass different from a solid such as quartz? Under what conditions could quartz be converted into glass? Sol. Glass is a supercooled liquid and an amorphous substance. Quartz is the crystalline form of silica (SiO 2 ) in which tetrahedral units SiO 4 are linked with each other in such a way that the oxygen atom of one tetrahedron is shared with another Si atom. Quartz can be converted into glass by melting it and cooling the melt very rapidly. In the glass, SiO 4 tetrahedra are joined in a random manner. 3. (i) Wh...