Chapter 8: Manufactured Substances in Industry Name: Tang Hui Xin Class: 4S3 Teacher: Puan Chan Yoke Bee FORM 4 CHEMISTRY PBL 1
CONTENT PAGE Table of contents No. Title Page 1. Glass 3-5 2. Ceramics 6-8 3. Composite materials and their importance 9-12
1. Glass WHAT IS GLASS? When silica is heated together with other chemicals, various types of glass with different properties are obtained. However, all types of glass have the same basic properties. Basic properties of glass Hard but brittle Chemically inert Transparent Waterproof Heat insulator Electrical insulator Major component : Silica, SiO₂
Types of glass Fused silica glass • Made from silica (silicon dioxide, SiO₂) • High melting point (1800°C) • Does not expand nor contract much when subjected to sudden temperature changes. • Example: telescope lens Soda-lime glass • Made from silica, SiO₂, soda (sodium carbonate, Na₂CO₃) and limestone (calcium carbonate,CaCO³). • Low melting point (1000°C) • Easily molded • Cannot withstand high temperatures and can easily crack when subjected to sudden temperature changes • Example: glass bottles and jugs
Borosilicate glass • Made from silica, SiO₂, soda, Na₂CO₃, limestone, CaCO₃, boron oxide, B₂O₃ and aluminium oxide, Al₂O₃ • Resistant to heat • Do not crack easily when subjected to thermal stress (low expansion coefficient) • Can be freezed and heated immediately without cracking. • Example: laboratory glassware Lead crystal glass • Made from silica, SiO₂, soda, Na₂CO₃ and lead(II) oxide, PbO • Softer and denser • Heavier and has a refractive index • Example: prisms
2. Ceramics WHAT IS CERAMIC? A ceramic is a solid made up of inorganic and nonmetallic substances. Ceramic is produced through the process of shaping and hardening by using heating technique at a high temperature. Basic properties of ceramics High thermal resistance Break easily Chemically inert Electrical insulator Hard and strong Heat insulator
Major components of traditional and advanced ceramics Traditional ceramics Major component: clay mixed with water Example: Kaolin Water and clay are mixed to form a soft, mouldable mixture mixture is heated at a very high temperature Used to make bricks, pottery and crockery Traditional ceramics Major component: Inorganic compounds Example: Oxides, carbides, nitrides Higher resistance to heat and abrasion More chemically inert Have superconduct ivity properties
Uses, properties and examples of ceramics
3. Composite materials and its importance WHAT IS COMPOSITE MATERIAL? A composite material is a material made from combining two or more non-homogeneous substances, that is matrix substance and strengthening substance. The matrix substance surrounds and binds the strengthening substance together. Types of composite materials Reinforced concrete Fibre glass Optical fibre Photochro mic glass Supercond uctors
Types of composite materials Reinforced concrete • Produced when steel bars or wire mesh (strengthening substance) is immersed in concrete (matrix substance). • Widely used in construction of bridges, dams and buildings. Fibre glass • Produced when plastic (matrix substance) is strengthened with glass fibres (strengthening substance). • Used to make helmets, car bumpers and printed circuit boards.
Optical fibre • Consists of three layers. • Innermost layer-(core) is made up of silica glass fibres (strengthening substance). • Second layer (cladding)- made up of glass or plastic (matrix substance) • Outermost layer- made of plastic that acts as a protective jacket • Used to transmit information and data in the form of light. • Light moves through the optical fibre (core section) in a series of total internal reflection • Core and cladding have different refractive indexes (to carry data in large capacity and not influenced by electromagnetic disturbances. • Replaced copper wires in videos cameras. • Connects computers in Local Area Network (LAN).
Photochromic glass • Formed when glass (matrix substance) is combined with silver chloride, AgC1 and copper(I) chloride,CuC1 (strengthening substance). • Darkens when exposed to sunlight. • Copper(I) chloride, CuC1 catalyses the reverse process so that the glass becomes transparent again in dim light. • Protects the user from UV rays. • Example: car windows, building windows and camera lenses. Superconductors • Composite material that has superconductivity properties other than alloys. • Used to make electromagnets, superconductor magnets or supermagnets. • Light and have strong magnetic force • Used in particle accelerators • Involved in Nuclear Magnetic Resonance (NMR) machines and Magnetic Resonance Imaging (MRI) machines.