Classify the following as amorphous or crystalline solids: Polyurethane, naphthalene, benzoic acid, teflon, potassium nitrate, cellophane, olyvinylchloride, fibre glass, copper.
| Substance | type of solid |
| Polyurethane | Amorphous solids |
| Nnaphthalene | Crystalline solids |
| benzoic acid | Crystalline solids |
| Teflon | Amorphous solids |
| Potassium nitrate | Crystalline solids |
| Cellophane | Amorphous solids |
| Polyvinylchloride | Amorphous solids |
| Fibre glass | Amorphous solids |
| Copper | Crystalline solids |
