Chapter 8: Chemicals in Industry 8.1 properties of alloys and their uses in industry 8.1.1 Alloy 1. 2. 3. 4. 5.
An alloy is a solid mixture of at least one metallic element melting in it. Examples: steel, pewter, bronze, brass, duralumin duralumin and etc. The mixture of metals in alloys follows a specific percentage rate. Alloying produces a new substance which has different properties from the original metal. Alloying is carried out to improve the weakness and structure of of pure metals. Pure metals are a) Soft and weak b) Rust easily, make it less shinny and dull: metal + oxide = metal oxide c) Less durable d) Not suitable for various uses 6. Alloys are better than pure metals because: a. More harder and stronger b. More resistant to corrosion c. Better appearance 7. Pure metals are weaker than alloy because, in pure metals atoms are arranged neatly in rows. The rows can slide over each other easily when force is applied. This makes the pure metal to be: a) Ductile b) Malleable c) Easily shaped 8. When another metal is added, its atoms stop the row from sliding over each other. This is because the added metal has atoms of a different size.
9. Comparison between a pure metal and an alloy Pure metal Atoms are arranged orderly and closely together The layers of atoms slide easily over one another Ductile and malleable.
Alloy Other atoms are randomly scattered and are filled between pure metal atoms. There is no layered structure. The pure metal atoms are unable to move because the addition of foreign atoms hols them in place. Harder, non-ductile and non-malleable
10. Composition, properties and uses of alloys in daily life. Type of alloy Brass
Composition 70% copper 30% zinc
Properties Hard and malleable Resistant to corrosion
Bronze
88% copper 12% tin
Duralumin
95% aluminium 5% copper
Hard and malleable Can withstand corrosion better than copper Shinny Light and strong Resists corrosion
Stainless steel
74% iron 18% chromium 8% nickel
Pewter
96% tin 3% copper 1% antimony 99% iron 1% carbon
High carbon steel Cupronickel
75% copper 25% nickel
Magnalium
70% aluminium 30% zinc
Same as carbon steel but its appearance is shinny Can withstand corrosion better than carbon steel Soft, shiny and malleable
Strong, hard High wear resistant Withstand great pressure Attractive, silvery appearance Hard and tough Light hard and strong
Uses Making kitchen appliances and ornaments Making decorative ornaments and trophies
Making aircraft bodies, bicycle frames and modern jets Cutlery like forks, spoons and surgical knives Building construction, bodies of cars, pipes Making decorative ornaments and drinking mugs Making of cutting tools, hammers and chisels Making of silver coins
Aircraft body frames and rims of racing car types
8.1.2 The importance of Alloys in Industry 1. Alloys are widely used in industries because they have more desirable properties than pure metals. 2. One of the main contributions of alloy is in the form of superconductor alloy. 3. Superconductor alloy: a. Are electrical conductors which do not have electrical resistant to the flow of electricity in certain temperature. b. Allow high current to flow through them without producing heat as compared to normal conductors. c. Also shows diamagnetic properties which are repelled by magnets.
d. Superconductor alloys are used to make very light, small and strong magnets in: i. The medical field- The magnetic resonance imaging (MRI) machine uses superconductor alloy to produce a strong magnetic field which helps medical specialist to do diagnosis more accurately before operation or other treatment. Superconductor alloys such as niobium-titanium and niobium-tin are used in construction of MRI apparatus. ii. Bullet trains- The train uses the help of a magnet to move as though it if floating. iii. The production of electrical energy- A magnetic superconductor alloy in a nuclear reactor can produce more electrical energy
8.2 Production and Uses of Ammonia in Industry 1. Ammonia is a: a. Colourless gas with pungent smell b. Very soluble in water c. Produces alkali (ammonium hydroxide) in water 2. In industry, ammonia is produced by Haber process Iron catalyst Nitrogen + Hydrogen Ammonia 450° C – 550° C, 200 atm 3. Ammonia and its compounds are used for: a. Making nitric acid in large scale through Ostwald process. Ammonia as the raw material. b. Making ammonium fertilisers which can supply nitrogen to plants Ammonia + sulphuric acid Ammonia + nitric acid Ammonia + carbon oxide
ammonium sulphate + water ammonium nitrate + water urea + water
c. As a cooling agent as ammonia gas is easily compressed and has a high heat capacity d. Making chemical substances such as in dyes, synthetic nylon fibres, pharmaceutics and refrigerants e. As a cleaning agent - Ammonia solution reacts with vegetable oil or hydrocarbon to produce cleaning agents f. Preventing the coagulations of rubber latex g. Making explosive substances such as trinitrotoluene (TNT)
Nictric acid
Household cleaners
Fertilisers
Uses of Ammonia Pharmaceuticals
Refrigerants
Nylon production
Explosives
8.3 Effects of Industrial Waste Disposal on the Environment 1. Without proper disposal, industrial waste can cause environment pollution. 2. Poisonous and harmful industrial wastes in all forms are released from factories and laboratories into the environment, causing pollution. 3. The two main industrial activities which cause the pollution are: a) The burning of fossil fuels b) The direct disposal of industrial wastes from the factories Sources of pollution Burning of fossil fuels in electrical power plants and other industrial facilities
Pollutants Air pollutants such as sulphur oxides, nitrogen oxides, hydrocarbons, carbon oxides and soot
Chemical industry
Toxic waste such as acids, alkali and heavy metals, oil and untreated waste matters
Effects on the environment a) Irritate the respiratory system, leading to asthma or chronic bronchitis b) Carbon monoxide reduces the ability of the blood to transport oxygen, causing headache and fatigue, mental impairment or even death. c) A high-level of carbon dioxide and other greenhouse gases in the atmosphere can cause global warming d) When acidic gases such as sulphur and nitrogen oxides dissolve in rain water, causes acid rain. Acid rain can damage the forest and aquatic ecosystems a) Heavy metals such as mercury can damage the brain and kidneys. It also can cause birth defects. b) Pollute the land and water, making it undrinkable
Mining and processing of radioactive minerals, nuclear power plant, nuclear weapon industry, medical and scientific research facilities Agricultural industry
Radioactive wastes
Excessive artificial fertilisers and pesticides and organic waste
c) Aquatic animals and plants are effected by dissolved oxygen level in water d) Vapours of benzene and hydrocarbons can move upwards and are inhaled by humans can cause cancer in ling term Exposure to radiation from radioactive wastes causes serious health problems in living things. These include various types of cancers, mutations, sterility and birth defects
a) Long term exposure to pesticides can cause a variety of cancers and birth defects b) Excessive fertilisers washed to the lakes cause eutrophication c) Open dumps of organic wastes are breeding grounds for disease vectors such as rats and flies. d) Methane gas is released when this organic waste is decomposed by microorganisms e) Aquatic animals and plants are effected by dissolved oxygen level in water
4. The control of industrial waste can be carried out through the following ways: a) Law enforcement a) Environmental Quality ( Scheduled Waste) Regulation, 1989 b) Environmental Quality (Clean Air) Regulation, 1978 c) Environmental Quality (Sewage and Industrial Effluents) Regulation, 1979 b) Education a) Campaigns b) Mass media c) Education curriculum c) Recycling waste d) The use of technology in treating industrial waste a) Using an electrostatic precipitator-traps ashes in the smoke b) Plasma torch- to convert toxic industrial waste to harmless substances c) Modern landfills d) Switch from fossil fuels to solar energy e) Using a scrubber f) Direct burning- agricultural wastes are directly burned in a heating furnace g) Disposal drums- to store radioactive wastes h) Biogas technology- process agricultural wastes naturally through digestion of anaerobic microorganism. i) Scrubber- to filter poisonous gases j) International cooperation i. Montreal protocol (1987) ii. Langkawi Declaration (1991) iii. Kuala Lumpur Declaration (1992)
iv. v.
Kyoto Protocol (1997) Rio Declaration on Environment and Development
8.4 The need for Preservation and conservation of the environment from Industrial waste Pollution 1. 2. 3. 4.
Preservation: effort to maintain the environment in a good condition. Conservation: management of the environment so as to prevent damage to the environment Uncontrolled and haphazard disposal of industrial waste will pollute the air and water Water pollution causes water source become unsuitable for human consumption and also threatens aquatic lives. 5. All waste produced by various industries have to be stored, transported and disposed properly. This is to ensure minimal destruction of the environment. 6. Air pollutants from industries will cause air pollution. When, the air is polluted by smoke, dust and soot: a) Haze occurs- respiratory problems, poses danger to road users b) Acid rain forms- health problems, plants and animals are affected 7. By controlling the disposal of industrial waste, the following can be achieved: a) Environmental pollution can be reduced. The air will be fresher and the river is cleaner. b) Guarantee the health and co-existence of humans and other organisms.
