Manufactured Substances in Chemical Industry

8/8/2019 Manufactured Substances in Chemical 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 materials.

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STAGE3: Conversion of trioxide to sulphuric acid i. 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.

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 isvary 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

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Sulphur Oxygen

S(s) +

O2(g) SO 2(g)

SO 2(g) +H2SO 4(aq) H2S2O7(l)H2S2O7(l) +H2O(l) 2H2SO 4(aq)

2SO(g) + O2(g) 2SO3(g)

Temperature: 450-500CPressure: 2-3 atmospheresCatalyst: Vanadium(V) oxide

OxygenUnreacted2%so 2 isflowed back to converter together with

The Contact Process

Outline Of Contact process


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SULPHUR DIOXIDE AND ENVIRONMENTAL POLLUTION

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 formsulphurous acidic.

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

4. Oxidation of sulphur acid by oxygen produce sulphuric acid, H2SO4, which falls to theearth 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, ammonianitric, 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 35.5C) 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. Thusaqueous 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.

Fe+(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 inthe volume ratio 1:3.

2. The gas nitrogen obtain form the fractional distillation of liquefied air. The hydrogengas is obtained form the cracking of petroleum or from the catalysed reaction of naturalgas, 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: 450-500Cii. 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 ammoniagas. The nitrogen and hydrogen that have not reacted are then flow back over the catalystagain in the reactor chamber.

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

AMMONIUM FERTILIZERS

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Nitrogen Hydrogen

N2 and H 2 are mixed in the proportion of 1:3

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

Temperature: 450-500CPressure: 200-500 atmospheresCatalyst used: Iron fillings

Liquidammonia

In cooling chamber Unreacted N 2 andH2 gases

In the reactor chamber

The Haber Process

Outline Of Habert process


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

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

3. The nitrogen compounds are usually soluble nitric salt, ammonia and ammonia saltwhich 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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1. The atom of pure metals are packed together closely. This causes the metal to have ahigh density

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

3. Heat energy can be transferred easily from one atom to the next by vibration. Thismake metal good conduct of heat.4. The freely moving outermost electrons within the metals 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 oneanother. This make pure metals soft, malleable and ductile.

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Force

Layer of atom slide

Metals are ductile

Force

The shape of themetal change

Matel are malleable


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WHAT ARE ALLOYS?

1. Pure metal are usually too soft for most uses. They also have a low resistance tocorrosion. 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 toiron, 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 callduralumin is produced. b)Improving the resistance to corrosion

i. 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 makestainless steel suitable for making surgical instrument and cutlery.

ii. Pure copper tarnish easily. When zinc (30%) is added, the yellow alloy which isknown 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 makingcoins.

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Alloy Composition Properties UsesHigh carbon steel 99% iron

1% carbonStrong, hard and

high wear resistance Making of cutting

tools, hammers andchisels

Stainless steel 80.6% iron

0.4% carbon18%chromium

1% nickel

Do not rust and

tarnish, strong anddurable

Making of surgical

instrument, knivesforks and spoons

Brass 70% copper 30% zinc

Hard, do not rust, bright appearance

Making of ornaments,electrical wiringand plug.

Bronze 90% copper 10% tin

Hard, do not corrodeeasily and durable

For casting bells,medals, swordsand statues

Pewter 90% tin2.5% copper

0.5% antimony

Ductile andmalleable, white

silvery appearance

Making of ornaments,souvenirs andmugs

Duralumin 95% aluminium4% copper

1%magnesium

Light, strong anddurable

Making part of aircrafts and racingcars

Cupronickel 75%copper 25%nickel

Attractive, silveryappearance, 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 joinedtogether 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 andrubber.

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

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

Some Common Addition Polymers

Name(s) Formula Monomer Properties Uses

Polyethylenelow density(LDPE)

(CH 2-CH 2)n ethyleneCH 2=CH 2

soft, waxy solid film wrap, plastic bags

Polyethylene

high density(HDPE) (CH2-CH 2)n

ethyleneCH 2=CH 2

rigid, translucentsolid

electrical

insulation bottles, toys

Polypropylene(PP) differentgrades

[CH 2-CH(CH 3)]n

propyleneCH 2=CHCH 3

atactic: soft, elasticsolidisotactic: hard,strong solid

similar to LDPEcarpet,upholstery

Poly(vinylchloride)(PVC)

(CH 2-CHCl) n

vinyl chlorideCH 2=CHCl

strong rigid solid pipes, siding,flooring

Poly(vinylidenechloride)(Saran A)

(CH 2-CCl 2)n

vinylidenechlorideCH 2=CCl 2

dense, high-meltingsolid seat covers, films

Polystyrene(PS)

[CH 2-CH(C 6H5)]n

styreneCH 2=CHC 6H5

hard, rigid, clear solidsoluble in organicsolvents

toys, cabinets packaging(foamed)

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Polyacrylonitrile(PAN, Orlon,Acrilan)

(CH 2-CHCN) n

acrylonitrileCH 2=CHCN

high-melting solidsoluble in organicsolvents

rugs, blanketsclothing

Polytetrafluoroethylene(PTFE, Teflon)

(CF 2-CF 2)n tetrafluoroethyleneCF 2=CF 2

resistant, smoothsolid

non-stick

surfaceselectricalinsulation

Poly(methylmethacrylate)(PMMA, Lucite,Plexiglas)

[CH 2-C(CH 3)CO 2CH3]n

methylmethacrylateCH 2=C(CH 3)CO2CH 3

hard, transparentsolid

lighting covers,signsskylights

Poly(vinyl acetate)(PVAc)

(CH 2-CHOCOCH 3)n

vinyl acetateCH 2=CHOCOCH3

soft, sticky solid latex paints,adhesives

cis-Polyisoprenenatural rubber

[CH 2-CH=C(CH 3)-CH 2]n

isopreneCH 2=CH-C(CH 3)=CH 2

soft, sticky solidrequiresvulcanizationfor practical use

Polychloroprene(cis + trans)(Neoprene)

[CH 2-CH=CCl-CH 2]n

chloropreneCH 2=CH-CCl=CH 2

tough, rubberysolid

synthetic rubber oil resistant

Uses of synthetic polymers

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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 colored, 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 materialcatches fire, poisonous fumes are produce causing air pollution.

b. Synthetic polymers are non-biodegradable. When there are discharge, they causelitter 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 productsare 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 SiO 2: 100% Transparent

High melting point Good heat

insulator

Lens Telescope mirrors Laboratory

apparatusSoda-lime glass SiO 2: 75%

Na 2O:15%CaO: 9%Other:1%

Low melting point,easily molded intodesired shape andsize

Low resistant tochemical attacks

Brittle

Drinking glass, bottles

Electric bulbs Window glass

Borosilicate glass SiO 2: 78%B2O3: 12% Na 2O: 5%CaO: 3%Al 2O3:2%

Resistant chemicalattack and durable

High melting point

Good insulator toheat

Cooking utensils Laboratory

glassware such as

conical flaks and boiling tubeLead crystal glass

(flint glass)SiO 2: 70%

Pbo/PbO 2:20% Na 2O: 10%

High refractiveindex

High density Attractive

glitteringappearance

Lenses and prisms Decorative

glassware and artobject

Imation jewellery

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CERAMICS

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

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

a. Are hard, strong but brittle b. Have high melting point and remain stable at high temperaturec. Are heat and electric instrumentd. Are resistant to corrosion and wear e. Are chemically not reactivef. Do not readily deform under stress

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

i. Ceramic are strong and hard, uses to make roof tiles, bricks cement, sinks, andtoilet 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 tarnisheasily 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 Elasticmodulus/ GPa

Hardness/ mohs

Oxide ceramicAlumina,AL 2O3Beryllia, BeOZirconia, ZiO

205425742710

3.973.015.68

380370210

988

Non-oxideceramicsBoroncarbide,B 4C3Silicon nitride,Si3, n 4

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 twoor more different substances such as metal, glass, ceramic and polymer.

2. Some common composite materials are:a. Reinforces concrete

b.Superconductor c. Fibre optic

d. Fibre glasse. Photochromic glass

REINFORCES CONCRETE

1. Concrete is hard, fireproof, waterproof, comparatively cheap and easy to maintain. It ismore 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 theelectric 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 amagnet. Superconductor are used to build magnetically levitate high-speed train (atabout 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 internetcommunication.

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 network

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c. 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.

FIBRE GLASS

1. Fibre glass is glass in the form of fine threads. Molten gas is dropped onto a refractoryrating 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 butis 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 strong

b. Light weighc. Resistant to fire and water d. 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 smallamount of copper (II) chloride are added to molten silicon dioxide, photochromic glassis formed.

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

3. Photochromic glass is suitable for making sunglasses.

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Manufactured Substances in Chemical Industry

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