chemistry form 4: chapter 9 (manufacture substances in industry)

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Understand the manufacture of sulphuric acid. Synthesise the manufacture of ammonia and its salts. Understand alloys. Evaluate the uses of synthetic polymer. Apply the uses of glass and ceramics. Evaluate the uses of composite materials. Appreciate various synthetic industrial materiala.

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(H4SO4) USES OF SULPHURIC ACID

1. Sulphuric acid is used to produce chemical fertilizer such as ammonium sulphate and potassium sulphate, which are highly soluble in water and can be easily obsorbed by plant.

2. Car batteries contain sulphuric acid which is used as the electrolyte.3. Sulphuric acid also used in the making of artificial silk-like fibres and rayon.4. Chemical like paints, dyes and drug use sulphuric acid as one of

their component materials.

MANUFACTURE OF SULPHURIC ACID

1. Sulphuric acid is manufactured in industry though contact process 2. The process contain three stage STAGE1: Production Of Sulphur Dioxide From Sulphur

i. Combustion of sulphur or sulphide ores in the air produce sulphur dioxide SO2.S(s)+O2(g)SO2(g)

sulphur

ii. sulphur dioxide is dried and purified.

STAGE2: Production Of Sulphur Trioxide From Sulphur Dioxide i. The purified sulphur dioxide SO2 and excess air are passed over vanadium(V)

oxide V2O5 at controlled optimum condition optimum condition to produce sulphur trioxide SO3.

2SO2(g)+O2(g) 2SO3(g)ii. The optimum used area) Temperature:450-500°Cb) Pressure: 2-3 atmospheres c) Catalyst: Vanadium(V) oxide

iii. Under controlled optimum conditions, 98% conversion is possible. Sulphur dioxide and oxygen that have not reacted are allowed to flow back again over the catalyst in the converter.

STAGE3: Conversion of trioxide to sulphuric acidi. Sulphur trioxide SO2 is dissolved in concentrated sulphuric acid H2SO4 to form oleum

H2S2O7 which is then diluted with water to form sulphuric acid H2SO4.

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SO3(g)+H2SO4(l)H2S2O7(l) Oleum

H2S2O7(l)+ H2O(l)2H2SO4(aq)

ii. The two reactions in stage3 are equivalent to adding sulphur trioxide directly into water.

SO3(g)+H2O(l)H2SO4(aq)

iii. The addition of sulphur trioxide directly into is not carried out because the reaction is vary vigorous; a lot of heat is given off. As a result, alarge cloud of sulphuric acid fumes is produced, which is corrosive and causes severe air pollution.

In the converter

SULPHUR DIOXIDE AND ENVIRONMENTAL POLLUTION

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Sulphur

Oxygen

S(s) + O2(g)SO2(g)

SO2(g) + H2SO4(aq)H2S2O7(l)H2S2O7(l) + H2O(l)2H2SO4(aq)

2SO(g) + O2(g) 2SO3(g)Temperature: 450-500°CPressure: 2-3 atmospheres Catalyst: Vanadium(V) oxideOxyge

Unreacted 2%so2 isflowed backto convertertogether with

The Contact Process

Outline Of Contact process

1. Sulphur dioxide is one of the by-product of contact process. It is a colourless and poisonous gas with a vary pungent smell.

2. Sulphur dioxide which escape into the air causes air pollution.3. Sulphur dioxide is an acidic which dissolves in water to form sulphurous acidic, H2SO3.

In the atmosphere, sulphur dioxide dissolve in water droplets to form sulphurous acidic.

SO2(g) + H2O(l) H2SO3(aq)

4. Oxidation of sulphur acid by oxygen produce sulphuric acid, H2SO4, which falls to the earth as acid rain. Sulphur trioxide is also easily oxidised in the air to form sulphur trioxide. Sulphur trioxide dissolve in rainwater to produce sulphuric acid.

SO3(g) + H2O(l) H2SO4(aq)

Acid rain and environmental pollution

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(NH3) USES OF AMMONIA

1. Ammonia that is produce commercially has many uses.2. It uses:

i. In the manufacture of chemical fertilizers such as ammonium sulphate, ammonia nitric, ammonia phosphate and urea.

ii. To manufacture nitric acid and explosive.iii. In the making of synthetic fibre and nylon.iv. As a degreasing agent in aqueous form to remove greasy stains in the kitchen.

PROPERTIES OF AMMONIA GAS

1. The physical properties of ammonia gas include the following:i. It colourless and has a pungent odour.

ii. It is vary soluble in water and form a weak alkaline solution.iii. It less dense then water.iv. It easily liquified (at about 35.5°C) when cool.

2. The chemical properties of ammonia gas:a) Ammonia gas dissolves in water to form a weak alkali.

NH3(g) + H2O(l) NH4+(aq) + OH-(aq)

b) The presence of hydroxide icon causes the aqueous solution to become alkaline. Thus aqueous ammonia solution:i. Turns red litmus paper blue.

ii. Reacts with acid to form only salt and waterin neutralization reaction.

NH3(aq) + HCI(aq) NH4CI(aq)

2NH3 + H2SO4(aq) (NH4)2SO4(aq)

iii. Reacts with solution of metallic cations to produce precipitates.

Fe²+(aq) + 2OH(aq) Fe (OH)2(s) (Form ammonia solution) Dirty green precipitate

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MANUFACTURE OF AMMONIA IN INDUSTRY

1. Ammonia is manufacture on a large scale in industry through the haber process. In this process, ammonia is formed form direct combination of nitrogen and hydrogen gas in the volume ratio 1:3.

2. The gas nitrogen obtain form the fractional distillation of liquefied air. The hydrogen gas is obtained form the cracking of petroleum or from the catalysed reaction of natural gas, CH4, with steam.

CH4(g) + H2O(g) CO(g) + 3H2(g)

3. The mixture of nitrogen and hydrogen gases is passed over an iron catalyst under controlled optimum condition as below to form ammonia gas.

i. Temperature: 450-500°Cii. Pressure: 200-500 atmospheres

iii. Catalyst used: Iron fillings

N2(g) + 3H2(g) 2NH3(g)

4. Under these control optimum condition, only 15% of the gas mixture turn into ammonia gas. The nitrogen and hydrogen that have not reacted are then flow back over the catalyst again in the reactor chamber.

5. The ammonia product is then cooled at a low temperature so that it condenses into a liquid in the cooling chamber.

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The Haber Process

AMMONIUM FERTILIZERS

1. Nitrogen is required in large amount by plant to make proteins which are necessary for growth and cell repair.

2. Most plant are not able to get a nitrogen supply directly from the air although it is abundant in the air (78%). Plants can only absorb soluble nitrogen compounds from soil through their roots.

3. The nitrogen compounds are usually soluble nitric salt, ammonia and ammonia salt which are manufacture as chemical fertilizer.

4. Reactions of ammonia with acids produce ammonium fertilizers.

NH3(aq) + HNO3(aq) NH4NO3(aq) Ammonium nitrate

3NH3(aq) + H3PO4(aq) (NH4)3PO4(aq) Ammonium phosphate

2NH3(aq) +H2SO4(aq) (NH4)2SO4(aq)

Ammonium sulphate

ARRANGEMENT OF ATOMS IN MATELS

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Nitrogen Hydrogen

N2 and H2 are mixed in the proportion of 1:3

N2(g) + 3H2(g) 2NH3(g)Temperature: 450-500°CPressure: 200-500 atmospheresCatalyst used: Iron fillings

Liquid ammonia

In cooling chamberUnreacted N2 and H2 gases

In the reactor chamber

Outline Of Habert process

1. The atom of pure metals are packed together closely. This causes the metal to have a hight density

2. The forces of attraction between atoms (metallic bonds) are strong. More heat energy is needed to overcome the metallic bond so that the atoms are further apart during the melting. This is why metals usually have hight melting point.

3. Heat energy can be transferred easily from one atom to the next by vibration. This make metal good conduct of heat.

4. The freely moving outermost electrons within the metal’s structure are able to conduct electricity. Metal are, therefore, good electrical conductors.

5. Since atoms of pure metal are of the same size, they are arranged orderly in a regular layered pattern. When a force is applied to metal, layer of atom slide easily over one another. This make pure metals soft, malleable and ductile.

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Force

Layer of atom slide

Metals are ductile

Force

The shape of the metal change

Matel are malleable

WHAT ARE ALLOYS

1. Pure metal are usually too soft for most uses. They also have a low resistance to corrosion. They rush and tarnish easily.

2. To improve the physical properties of metal, a small amount of another element (usually metal) is added to form another an alloy.

3. An alloy is a mixture of two or more metals (something non-metal) in a specific proportion. For example:

a. Bronze (90% of copper and 10% of tin)b. Steel (99% of iron and 1% of carbon)

4. The purposes of making alloys include the following:a) Increase the strength

i. Pure iron is soft and vary malleable. When a small amount of carbon is added to iron, an alloy, steal is formed. The more carbon is added, the stronger the steel becomes.

ii. Pure aluminium is light but not strong. With a small amount of copper and magnesium are added to aluminium, a strong, light and durable alloy call duralumin is produced.

b) Improving the resistance to corrosioni. Iron rust easily but stainless steel which contains 80.6% of iron, 0.4% of carbon,

18% of chromium and 1% of nickel does not rush. These properties make stainless steel suitable for making surgical instrument and cutlery.

ii. Pure copper tarnish easily. When zinc (30%) is added, the yellow alloy which is known as brass develops a high resistance to corrosion.

c) Enhancing the appearancei. Pewter, an alloy of tin (97%), antimony and copper is not only hard but also has

a more beautiful white silvery appearance.ii. When copper is mixed with nickel to form cupronickel, an alloy that has an

attractive silvery, bright appearance is formed which is suitable for making coins.

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Alloy Composition Properties UsesHigh carbon steel 99% iron

1% carbonStrong,hard and high

wear resistance Making of cutting

tools, hammers and chisels

Stainless steel 80.6% iron0.4% carbon

18%chromium1% nickel

Do not rust and tarnish, strong and

durable

Making of surgical instrument, knives forks and spoons

Brass 70% copper30% zinc

Hard, do not rust, bright appearance

Making of ornaments, electrical wiring and plug.

Bronze 90% copper10% tin

Hard, do not corrode easily and durable

For casting bells, medals, swords and statues

Pewter 90% tin2.5% copper

0.5% antimony

Ductile and malleable, white

silvery appearance

Making of ornaments, souvenirs and mugs

Duralumin 95% aluminium4% copper

1%magnesium

Light, strong and durable

Making part of aircrafts and racing cars

Cupronickel 75%copper25%nickel

Attractive, silvery appearance, hard and

tough

Making of silver coins

Composition, properties and uses of alloys

The formation of alloy

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WHAT ARE POLYMER

1. Molecule that consist of a large number of small identical or similar units joined together repeatedly are called polymer.

2. The smaller molecules that make up the repeating unit in polymer are caller monomer.3. The process of joining together a large number of monomers to form a long chain

polymer is called polymerisation.4. Polymer can be naturally occurring or man-made (synthetic). Natural polymer are found

in plant and in animals for example of natural polymers are starch cellulose, protein and rubber.

5. Two type of polymerisation in producing synthetic polymer are additional polymerisation.

6. Double bonds between two carbon atoms usually undergo addition polymerisation.

Some Common Addition Polymers

Name(s) Formula Monomer Properties Uses

Polyethylenelow density (LDPE)

–(CH2-CH2)n–ethyleneCH2=CH2

soft, waxy solidfilm wrap, plastic bags

Polyethylenehigh density (HDPE)

–(CH2-CH2)n–ethyleneCH2=CH2

rigid, translucent solid

electrical insulationbottles, toys

Polypropylene(PP) different grades

–[CH2-CH(CH3)]n–

propyleneCH2=CHCH3

atactic: soft, elastic solidisotactic: hard, strong solid

similar to LDPEcarpet, upholstery

Poly(vinyl chloride)(PVC)

–(CH2-CHCl)n–

vinyl chlorideCH2=CHCl

strong rigid solidpipes, siding, flooring

Poly(vinylidene chloride)(Saran A)

–(CH2-CCl2)n–

vinylidene chlorideCH2=CCl2

dense, high-melting solid

seat covers, films

Polystyrene(PS)

–[CH2-CH(C6H5)]n–

styreneCH2=CHC6H5

hard, rigid, clear solidsoluble in organic solvents

toys, cabinetspackaging (foamed)

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Polyacrylonitrile(PAN, Orlon, Acrilan)

–(CH2-CHCN)n–

acrylonitrileCH2=CHCN

high-melting solidsoluble in organic solvents

rugs, blanketsclothing

Polytetrafluoroethylene(PTFE, Teflon)

–(CF2-CF2)n–tetrafluoroethyleneCF2=CF2

resistant, smooth solid

non-stick surfaceselectrical insulation

Poly(methyl methacrylate)(PMMA, Lucite, Plexiglas)

–[CH2-C(CH3)CO2CH3]n–

methyl methacrylateCH2=C(CH3)CO2CH3

hard, transparent solid

lighting covers, signsskylights

Poly(vinyl acetate)(PVAc)

–(CH2-CHOCOCH3)n–

vinyl acetateCH2=CHOCOCH3

soft, sticky solidlatex paints, adhesives

cis-Polyisoprenenatural rubber

–[CH2-CH=C(CH3)-CH2]n–

isopreneCH2=CH-C(CH3)=CH2

soft, sticky solidrequires vulcanizationfor practical use

Polychloroprene (cis + trans)(Neoprene)

–[CH2-CH=CCl-CH2]n–

chloropreneCH2=CH-CCl=CH2

tough, rubbery solid

synthetic rubberoil resistant

Uses of synthetic polymers

SYNTHETIC POLYMERS IN DAILY LIFE

1. Synthetic polymers have many advantages over other type of materials:a. They are cheap, light-weight and translucent.b. They are easily coloured, easily moulded and shaped.c. They are non-corrosive, waterproof and good insulator.d. They are durable and long lasting because they are resistant to decay, rusting and

chemical attacks.2. There are disadvantage using synthetic polymer:

a. Most of the synthetic polymer are flammable. When a synthetic polymer material catches fire, poisonous fumes are produce causing air pollution.

b. Synthetic polymers are non-biodegradable. When there are discharge, they cause litter problem and pollute the environment.

c. Plastic container that are left aside in an open area collect rainwater which becomes the breeding ground for mosquitoes.

d. There are limitation in recycle have to be separated out as the addition of non-recyclable polymers in the mixture affect the properties of the recycled polymers.

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WHAT ARE GLASS

1. Glass is one of the most useful but inexpensive materials in the world. Many products are made from glass because of its specials properties.

2. Glass is:a. Transparent, hard but brittle.b. A heat and electric insulator.c. Resistant to corrosion.d. Chemical not reaction and therefore resistant to chemical attack.e. Easy to maintain.

Type of glass Composition Properties UsesFused glass SiO2: 100% Transparent

High melting point Good heat

insulator

Lens Telescope mirrors Laboratory

apparatusSoda-lime glass SiO2: 75%

Na2O:15%CaO: 9%Other:1%

Low melting point, easily molded into desired shape and size

Low resistant to chemical attacks

Brittle

Drinking glass, bottles

Electric bulbs Window glass

Borosilicate glass SiO2: 78%B2O3: 12%Na2O: 5%CaO: 3%Al2O3:2%

Resistant chemical attack and durable

High melting point Good insulator to

heat

Cooking utensils Laboratory

glassware such as conical flaks and boiling tube

Lead crystal glass (flint glass)

SiO2: 70%Pbo/PbO2:20%

Na2O: 10%

High refractive index

High density Attractive

glittering appearance

Lenses and prisms Decorative

glassware and art object

Imation jewellery

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CERAMICS

1. Traditional silicate ceramics are made by heating aluminosilicate clay such as kaolin to a vary high temperature.

2. Ceramics have many special properties that make them one of the most useful materials in our everyday life. That:

a. Are hard, strong but brittleb. Have high melting point and remain stable at high temperature c. Are heat and electric instrumentd. Are resistant to corrosion and weare. Are chemically not reactivef. Do not readily deform under stress

3. Ceramic play important role in our daily life. They are uses as a. Construction materials

i. Ceramic are strong and hard, uses to make roof tiles, bricks cement, sinks, and toilet bowls.

ii. They are also used to make refractory bricks because high resistant to heat.b. Decorative items

i. To make pottery, china plates, and porcelain vases since they do not tarnish easily and are durable.

ii. They are used to make bathroom fixture such as floor and wall tiles.c. Electrical insulator

i. Ceramic are used to make electrical insulator in electrical items such as toasters, fridges and electrical plug.

Materials Melting point/ °C

Density/G cm-3 Elastic modulus/ GPa

Hardness/ mohs

Oxide ceramicAlumina,AL2O3

Beryllia, BeOZirconia, ZiO

205425742710

3.973.015.68

380370210

988

Non-oxide ceramicsBoron carbide,B4C3

Silicon nitride, Si3, n4

23502830

1900

2.503.16

3.17

280400

310

99

9MetalsAluminiumSteel

6601515

2.707.86

70205

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WHAT ARE COMPOSITE MATERIALS

1. A composite materials (or composite) is a structure of materials that is formed by two or more different substances such as metal, glass, ceramic and polymer.

2. Some common composite materials are:a. Reinforces concreteb. Superconductorc. Fibre opticd. Fibre glasse. Photochromic glass

REINFORCES CONCRETE

1. Concrete is hard, fireproof, waterproof, comparatively cheap and easy to maintain. It is more important construction materials.

2. The reinforces is a combination of concrete and steel.

SUPERCONDUCTOR

1. Metal such as copper and aluminium are good conductor of electricity, but 20% of the electric energy is lost in the form of heat during transmission.

2. Super conductor are materials that have no resistance to the flow of electricity at a particular temperature. Hence, 100% electricity transmission is possible.

3. One of the most dramatic properties of a superconductor is its ability to levitate a magnet. Superconductor are used to build magnetically levitate high-speed train (at about 552 km/h).

4. Superconductor are used to make chips for smaller and faster supercomputer. Superconductor also play an important role in high speed data processing in internet communication.

FIBRE OPTIC

1. Fibre optic is a composite material that in used to transmit signals for light wave.2. Fibre optic is used in

a. Telecommunicate where the telephone substation are liked by fibre optic cables.b. Domestic cable television networkc. Closed circuit television security system.

3. Fibre optic also used in medical fields. It is used in a number of instrument which enable the investigation for internal body part without having to perform surgery.

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FIBRE GLASS

1. Fibre glass is glass in the form of fine threads. Molten gas is dropped onto a refractory rating disc when the glass flies off the disc glass to form fibre.

2. Fibre glass is strong than steel, do not burnt, stretch or rot, resistant to fire and water but is brittle.

3. When fibre glass added to a plastic, a new composite material fibre glass reinforces plastic is formed.

4. Fibre glass reinforces plastic has more superior properties than glass and plastic. It isa. Extremely strongb. Light weighc. Resistant to fire and waterd. Can be molded, shaped and twisted

PHOTOCHROMIC GLASS

1. When 0.01 to 0.1% of silver chloride (a type of photochromic substances) and a small amount of copper (II) chloride are added to molten silicon dioxide, photochromic glass is formed.

2. The photochromic glass has a special properties. It darken when exposed to strong sunlight or ultraviolet.

3. Photochromic glass is suitable for making sunglasses.

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