Chapter 9 : Manufactured Substances in Industry

By :Mohd. Rozaini Ermi Bin Herman

From :4 Mutiara

Teacher :Tia Yee Hien

Sulphuric Acid Uses of Sulphuric Acid :

1. Sulfuric acid is used in manufacturing fertilizers like ammonium sulfate, super phosphate of lime, etc.

2. It is used in manufacturing of hydrochloric acid, nitric acid, phosphoric acid, ether, plastics, metal sulfates, cellophane, dyes, drugs, perfumes, disinfectants and even glue.

3. Sulfuric acid is used to manufacture nitroglycerin acid and tri-nitro-toluene(TNT) in the explosive industry.

4. Sulfur and tarry compounds in the gasoline are removed by using sulfuric acid.

5. It is used as an electrolyte in lead acid batteries.

6. Sulfuric acid uses also includes removal of oxides from iron and steel before electroplating or galvanizing.

Manufacture of Sulphuric Acid

Stages in Contact Process :Stage 1 :

In the furnace, molten sulphur is burnt in dry air to produce sulphur dioxide. The gas produced is purified and cooled.

Stage 2 :

In the converter, sulphur dioxide and excess oxygen gas are passed over a few plates on vanadium(V) oxide catalyst at 450ºC to produce sulphur trioxide.

Stage 3 :

In the absorber, the sulphur trioxide is first reacted with concentrated sulphuric acid to form a product called oleum.

Sulphur dioxide and environmental pollution

Sulphur dioxide, is one of the by-products of the Contact Process. It can cause environmental pollution. Almost all sulphur dioxide in the air comes from the burning of fossil fuels containing sulphur. Inhaling sulphur dioxide causes coughing, chest pain, shortness of breath, bronchitis and lung diseases.

Sulphur dioxide can cause acid rain. Natural rainwater has a pH of about 5.4. Acid rain occurs when pH of the rain is between 2.4 and 5.0. This is due to the reaction of sulphur dioxide with rainwater.

2SO2 + O2 + 2H2O 2H2SO4

Ammonia and Its SaltsUses of Ammonia :

1. Most of the ammonia used in the world is used in fertilizer either in salt or liquid form.

2. Almost all synthetically derived nitrogen is made from ammonia. Nitric acid is used in fertilizers and explosives.

3. Household ammonia is used as a surface cleaner in a diluted form. It most commonly used to clean glass, porcelain and stainless steel as it leaves no streaks.

4. Ammonia is the main ingredient in most oven cleaners.5. Ammonia is used in industrial refrigeration applications and

hockey rinks as it has favorable vaporization properties.6. It is used in geothermal power plants in an ammonia-water

mixture that is boiled.7. Ammonia is used to scrub Sulfur dioxide from the burning fossil

fuels used in power plants. It is also used to neutralize the nitrogen oxide produced by diesel engines.

8. It is used in animal feed as an antimicrobial. It is also used to disinfect beef products before sale.

9. Liquid ammonia is used in textiles to treat cotton materials and in the pre-washing of wool.

Properties of ammonia

1. is alkaline.2. is a colourless gas.3. has a pungent smell.4. is less dense than air.5. burns in oxygen gas, but not in

the air.6. is very soluble in water.7. gives a white fume when reacted

with hydrogen chloride gas.

Manufacture of Ammonia through Haber Process

Preparation of ammonium fertilizers

Ammonium fertilizers are one of the chemical fertilizers added to soil to replace the elements used up by plants. The major plant nutrients include nitrogen, phosphorus, potassium and calcium. Ammonium fertilizers can be prepared from the reaction between ammonia and an acid.

AlloysPure aluminium is not enough tu withstand the great

stress put on the wings of an aeroplane when it is flying. How can we combine the low density of aluminium with the strength needed to make the body of an aeroplane? Alloys give us the answer.

Arrangement of atoms in metalsMost metals are solid. Pure metals are made up of

the same type of atoms and are of the same size. The arrangement of the atoms in metals gives the metals their ductile and malleable properties. The orderly arrangement of atoms in metals enables the layers of atoms to slide on one another when force is applied, as shown in Figure 9.1. Thus, metals are ductile or can be stretched.

Figure 9.1 : Ductility of Metals.

There are some imperfections in the orderly arrangement of atoms in metals that allow some empty spaces in between the atoms. When a metal is knocked, atoms slide. This why metals are malleable or can be shaped.

Figure 9.2 : Malleability of metal

What are alloys ?An alloy is a mixture of two or more elements with a

certain fixed composition in which the major component is a metal. Most pure metals are weak and soft. The properties of pure metals can be improved by making them into alloys. The aim is to make the pure metals stronger, harder, resistant to corrosion, have a better furnish and luster. Alloys such as bronze, brass, steel, stainless steel, duralumin and pewter are commonly used in our daily life.

The composition, properties and uses of some alloys

Alloy Composition Properties UsesBronze 90% copper

10% tin Hard and strong Does not corrode

easily Has shiny surface

In the building of statues or monuments

In the making of medals, swords and artistic materials

Brass 70% copper 30% zinc

Harder than copper In the making of musical instruments and kitchenware

Steel 99% iron 1% carbon

Hard and strong In the construction of buildings and bridges

In the building of the body of cars and railway tracks

StainlessSteel

74% iron 8% carbon 18% chromium

Shiny Strong Does not rust

In the making of cutlery

In the making of surgical instruments

Duralumin 93% aluminium 3% copper 3% magnesium 1% manganese

Light Strong

In the building of the body of aeroplanes and bullet trains

Pewter 96% tin 3% copper 1% antimony

Lustre Shiny Strong

In the making of souvenirs

The arrangement of atoms in alloys

The presence of atoms of other metals that are of different sizes disturb the orderly arrangement of atoms in the metal. This reduces the layer of atoms from sliding. Thus, an alloy is stronger and harder than its pure metal.

Figure 9.3 : Arrangement of atoms in steel

Synthetic PolymersWhat are polymers ?

Polymers are large molecules made up of many identical repeating sub-units called monomers which are joined together by covalent bonds.

Monomers are joined into chains by a process of repeated linking known as polymerization.

A polymer may consists of thousands of monomers. Some polymers occur naturally. Starch, cellulose, wool, protein, silk and natural rubber are some examples of naturally occurring polymers.

On the other hand, synthetic polymers are man-made polymers.

Monomers in synthetic polymers

Synthetic polymer Monomer UsesPolythene Ethene Plastic bags, shopping

bags, plastic containers and insulation for electrical wiring

Polypropene Propene Piping, bottle crates, carpets, car batteries and ropes

Polyvinyl chloride, PVC Chloroethene Artificial leather, water pipes and records

Perspex Methylmethacrylate Safety glass, reflectors, traffic signs and lens

Terylene Hexane-1,6-diolBenzene-1,4-dicarboxylic acid

Clothing, sails and ropes

Nylon Hexane-1,6-diamineHexane-1,6-dioic acid

Ropes, clothing and carpets

Should we continue using synthetic polymers ?

Synthetic polymers are very stable and do not corrode or decay. However, this also means that they are difficult to dispose. They are not easily biodegradable. Hence, they may cause pollution, blockage of drainage systems and flash floods. When they are burnt, they give out harmful and poisonous gases which have a pungent smell.

Although synthetic polymers pose environmental problems, we can still continue using them but in a wiser manner. We should reduce, reuse and recycle synthetic polymers as much as possible. The use of biodegradable polymers should be encouraged. We should also find alternatives to synthetic polymers.

Glass and Ceramics Glass

- The major component of glass is silica or silicon dioxide, which found in sand.- Properties of glass: Transparent, hard but brittle, chemically inert, heat insulator, electrical insulator, impermeable to liquid.

Fused glass (SiO 2 ) - Highly heat-resistant glass

- High transparency- High melting point

- Resistant to chemical attackUses

- Laboratory glassware,lenses, telescope, mirrors

Borosilicate glass(SiO 2 , Na 2 O, CaO, Al 2 O 3 ,B 2 O 3 )

- Low thermal expansion coefficient- Resistant to heat and chemical attack

- High melting pointUses

- Cooking utensuls, laboratory glassware, automobile headlights

Soda-lime glass (SiO 2 , Na 2 O, CaO) - Good chemical durability

- High thermal expansion coefficient- Easy to make into different shapes

- Low melting pointUses

- Bottles, window panes, mirrors, electrical bulbs, flat glass and all kind of

glass containers.

Lead crystal glass (SiO 2 , Na 2 O, PbO, K 2 O, Al 2 O 3 )

- Soft and easy to melt- High density

- High refractive indexUses

- Lead crystal glassware, art objects, lens, prisms

and chandeliers

Ceramics- Ceramics are made from clay, for example kaolin, a hydrated

aluminiumsilicate.- When the clay is heated to a very high temperature, they undergo a

series of chemical reaction and are hardened permanently to form ceramics.

- Ceramics are very hard, brittle, have a very high melting point, chemically inert and do not corrode.

- The are good insulators of electricity and heat.- Uses of ceramics: construction materials – bricks, tiles, cement and pipes.- Ornamental articles – bowls, cups, plates, vase and porcelain.- Electrical insulators – spark plugs, fuses, insulators in electric iron and

oven.- Superconductors.

Composite Materials- Composite materials is a structural material that is formed by combining two or more different substances such as metal, alloys, glass, ceramics and polymers.

- The resulting material has properties that are superior than those of the original components.

- Composite materials are created for specific application.

Composite material

Component Properties of component

Properties of composite

Uses of composites

Reinforced concrete Concrete - Hard but brittle- Low tensile strength

- Stronger- Higher tensile strength- Does not corrode easily- Cheaper- Can be moulded into any shape- Can withstand very high applied forces- Can support very heavy loads

- Construction of roads- Rocket launchingpads- High-rise buildings

Steel - Strong in tensilestrength- Expensive- Can corrode

Superconductor - Copper (II)oxide- Bariumoxide

Insulators ofelectricity

- Conducts electricity without resistance when cooled by liquid nitrogen

- Magnetically levitatedtrain- Transformers- Electric cable- Computer parts- Amplifier

Photochromic glass Glass - Transparent- Not sensitive to light

- Reduce refraction of light- Control the amount of light passes through itautomatically- Has the ability to change colour and become darker when exposed to ultravioletLight

- Information displaypanels- Light detector devices- Car windshields- Optical lens

Silver chloride or silver bromide

- Sensitive to light

Fibre optics Glass withlow refractionindex

- Transparent- Does not reflect light rays

- Low material cost- Reflect light ray and allow to travel along the fibre- Can transmit electronic data or signals, voice andimages in a digital format, in the form of light along the fine glass tubes at great speeds

- Transmit data using lightwaves in telecommunications- Instruments for examining internal parts of the body or inspecting the interiors ofmanufactured structural products

Glass with higher refractiveindex

Fibre glass Glass - High density- Strong butbrittle- Non-flexible

- High tensile strength- Moulded and shaped- Inert to chemicals- Light- Strong- Tough- Not inflammable- Impermeable to water- Resilient- Flexible

- Car bodies- Helmets- Skies- Rackets- Furniture- Water storage tanks- Small boats

Polyesterplastic

- Light- Flexible- Inflammable- Elastic but weak