Folio Chemistry 2009 Print

42
CHEMISTRY END OF YEAR HOMEWORK. CHAPTER 9 : MANUFACTURED SUBSTANCES IN INDUSTRY Name: Mohammad Firdaus Bin Ahmad Class: 4 ALFA (2009)

Transcript of Folio Chemistry 2009 Print

Page 1: Folio Chemistry 2009 Print

CHEMISTRY END OF YEAR

HOMEWORK.

CHAPTER 9 :

MANUFACTURED SUBSTANCES

IN INDUSTRY

Name: Mohammad Firdaus Bin Ahmad

Class: 4 ALFA (2009)

Teacher : Sir Sim

School: Sultan Abdul Hamid College

Page 2: Folio Chemistry 2009 Print

CONTENT

Content Page

Introduction 3

9.1 Sulphuric acid

9.1.1 Properties of sulphuric acid 4

9.1.2 The uses of sulphuric acid 5

9.1.3 The industrial process in manufacture of sulphuric acid 9

9.1.4 Environmental pollution by sulphuric acid 12

9.2 Ammonia and its salt

9.2.1 Properties of ammonia 13

9.2.2 The uses of ammonia 16

9.2.3 The industrial process in manufacture of ammonia 17

9.3 Alloys

9.3.1 Physical properties of pure metals 18

9.3.2 Meaning and purpose of making alloys 20

9.4 Synthetic polymers

9.4.1 The meaning and types of polymers 21

9.4.2 Advantages of synthetic polymers 23

9.4.3 Environmental pollution caused by synthetic polymers 23

9.4.4 Methods to overcome the environmental pollution caused

by synthetic polymers

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9.5 Glass and ceramics 24

9.6 Composite material 28

Conclusion 30

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References 31

INTRODUCTION

All the objects that exist around us are made up of chemical substances. These

objects exist an element, compound or mixture. All these objects contribute benefit to

humankind. As time goes on, human has done many researches to ensure all these

chemical substances will be enough for the use of themselves.

Chapter 9 of Form 4 syllabus introduces the students with manufactured

substances in industry. This is important for the students to appreciate the knowledge of

chemistry that is still new for themselves. Personally, I think that this chapter is an

interesting chapter as it revealed the way of scientist produces the material around me. It

also gives me new knowledges of the uses of chemical substances that I usually found in

the laboratories.

I hope, by learning this chapter, I will be more interested in learning chemistry as

it will help me in the future. All the equations from this chapter make me more

understand of the previous chapters.

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9.1 SULPHURIC ACID

9.1.1 Properties of sulphuric acid

1. Sulphuric acid is a strong mineral acid.

2. Its molecular formula is H2S O 4.

3. It is soluble in water.

4. Sulphuric acid is a non-volatile diprotic acid.

5. It is a highly corrosive, dense and oily liquid.

6. Concentrated sulphuric acid is a viscous colourless liquid.

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Figure 9.1 A molecule of sulphuric acid.

Properties of sulphuric acid

Non-volatileacid

Diprotic acid

Soluble in water

Highly corrosive

Oilyliquid

Viscous colourless

liquid

Dense

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Figure 9.2 Properties of sulphuric acid

9.1.2 The uses of sulphuric acid

1) To manufacture fertilizers

There are many fertilizers that can be made of sulphuric acid. Some of them are:

a) Calcium dihydrogen phosphate (superphosphate)

b) Ammonium sulphate

c) Potassium sulphate

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2 H2SO4 + Ca3(PO4) 2 → Ca(H2 PO4) 2 + 2CaSO4

sulphuric acid + tricalcium phosphate → calcium dihydrogen phosphate

H2SO4 +2NH3 → (NH4) 2SO4

sulphuric acid + aqueous ammonia → ammonium sulphate

H2SO4 +2NH3 → (NH4) 2SO4

sulphuric acid + aqueous ammonia → ammonium sulphate

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2) To manufacture detergents

Sulphuric acid reacts with hydrocarbon to produce sulphonic acid. Sulphonic acid is then

neutralized with sodium hydroxide to produce detergents. Examples of hydrocarbon

3) To manufacture synthetic fibres

Synthetic fibres are polymers ( long chain molecules). Rayon is an example of a synthetic

fibre that is produced from the action of sulphuric acid on cellulose.

4) To manufacture paint pigments

The white pigment in paint is usually barium sulphate, BaSO4. The neutralization of

sulphuric acid and barium hydroxide produces barium sulphate.

5) As an electrolyte in lead-acid accumulators

6) To remove metal oxides from metal surfaces before electroplating

7) To manufacture pesticides

8) The uses of sulphuric acid in school laboratories are:

a. As a strong acid

b. As a drying or dehydrating agent

c. As an oxidizing agent

d. As a sulphonating agent

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e. As a catalyst

Figure 9.3 Uses of sulphuric acid

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Uses of sulphuric acid

Manufacture pesticides

Remove metal oxides from metal

surfaces before

electroplating

As an electrolyte in

lead-acid accumulators

Manufacture paint

pigments

Manufacture synthetic

fibres

Manufacture detergents

Manufacture fertilizers

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As an acid2%

Fertilisers32%

Other chemicals

16%

Paint pigment15%

Detergents12%

As an electrolyte

10%

Synthetic fibres9%

Metal cleaning2% Dyes

2%

Figure 9.4 Uses of sulphuric acid in industry

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9.1.2 The industrial process in manufacture sulphuric acid

1. Sulphuric acid is manufactured by the Contact process.

2. Sulphuric acid is produced from sulfur, oxygen and water via the contact

process.

3. The Contact process involves three stages.

4. Stage I: Production of sulphur dioxide gas, SO2.

This can be done by two methods,

a) Burning of sulphur in dry air.

b) Burning of metal sulphide such as zinc sulphide in dry air.

5. Stage II: Conversion of sulphur dioxide to sulphur trioxide SO3.

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Sulphur → Sulphur dioxide → Sulphur trioxide → Sulphuric acid I II III

S + O2 → SO2

2ZnS + 3O2 → 2SO2 + 2ZnO

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This is then oxidised to sulfur trioxide under the following conditions:

a) The presence of a vanadium(V) oxide as a catalyst.

b) A temperature of between 450°C to 550°C.

c) A pressure of one atmosphere

   

6. Stage III: Production of sulphuric acid

a) Sulphur trioxide is dissolved in concentrated sulphuric acid, H2SO4 to produce oleum,

H2S2O7

b) Oleum is reacted with water to form concentrated H2SO4.

7. In stage II, sulphur dioxide is dried first before being added to dry air to

produce sulphur trioxide. This is:

a) To remove water vapour

b) To remove contaminants

8. In stage III, sulphur trioxide is not dissolved directly in water to produce sulphuric

acid. This is because:

a) sulphur trioxide has low solubility in water

b) sulphur trioxide reacts violently and mists are formed instead of

a liquid

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2 SO2 + O2 → 2 SO3

H2SO4+ SO3 →

H2S2O7

H2S2O7+ H2O → 2 H2SO4

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burned in air

a) the presence of a vanadium(V) oxide as a catalyst.

b) a temperature of between 450°C to 550°C.

c) a pressure of one atmosphere

dissolved in sulphuric acid, H2SO4

diluted with equal volume of water H2O

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Sulphur or metal sulphide

Sulphur dioxide, SO2

Sulphur trioxide, SO3

Oleum, H2S2O7

Concentrated sulphuric acid H2SO4

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Figure 9.5 Flowchart of Contact process

9.1.3 Environmental pollution by sulphuric acid

1. Sulphur dioxide is the main byproduct produced when sulfur-containing fuels

such as coal or oil are burned.

2. Sulphuric acid is formed by atmospheric oxidation of sulphur dioxide in the

presence of water. It also produces sulphurous acid.

3. Sulphuric acid and sulphurous acid are constituents of acid rain.

4. Acid rain can cause many effects such as:

i. Corrodes concrete buildings and metal structure

ii. Destroys trees and plants

iii. Decrease the pH of th soil and make it become acidic

iv. Acid rain flows into the rivers and increases the acidity of water and kill

aquatic living things.

5. Hence, we must reduce the sulphur dioxide from the atmosphere by:

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i. Use low sulphur fuels to reduce the emission of sulphur dioxide in exhaust

gases

ii. Remove sulphur dioxide from waste air by treating it with calcium

carbonated before it is released

9.2 AMMONIA AND ITS SALT

9.2.1 Properties of ammonia

1. A colorless, pungent gas.

2. Its molecular formula is NH3

3. It is extremely soluble in water.

4. It is a weak alkali.

5. It is about one half as dense as air

6. It reacts with hydrogen chloride gas to produce

white fumes of ammonium chloride.

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NH3 + HCl → NH4Cl

Figure 9.6 A molecule of ammonia.

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7. Ammonia is alkaline in property and reacts with dilute acids in neutralization

to produce salts. For examples:

8. Aqueous solutions of ammonia produces OH − ions (except Na+ ion, K+ ion,

and Ca 2+ ion) forming metal hydroxides precipitate.

9. Some metal hydroxides such as zinc hydroxide and copper (II) hydroxide

dissolves in excess aqueous ammonia to form complexes.

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2NH3 + H2SO4 → (NH4) 2SO4

NH3 + HNO 3 → NH4NO 3

Fe3+ + 3OH− → Fe(OH) 3

Brown precipitate

Mg2+ + 2OH− → Mg(OH) 2

White precipitate

Zn(OH)2 + 4NH3→ [Zn(NH3)4] 2++ 2OH−

Cu(OH)2 + 4NH3→ [Cu(NH3)4] 2+ + 2OH

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Properties of ammonia

Colorless Pungentsmell

Extremely soluble in

waterWeakalkali

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Figure 9.7 Properties of ammonia

9.2.2 The uses of ammonia

1.The major use of ammonia and its compounds is as fertilizers.

2.Ammonia is also used for the synthesis of nitric acid.

3.Ammonium fertilizers contain ammonium ions, NH4+, that can be converted into

nitrate ions by bacteria living in the soil.

4.Nitrogen is absorbed by plants to produce protein in the form of nitrates, NO3−,

which are soluble in water.

5.The effectiveness of ammonium fertilizers is determined by the percentage of

nitrogen by mass in them. The fertilizer with a higher percentage of nitrogen is

more effective.

6.The percentage of nitrogen by mass can be calculated using this formula:

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Mass of nitrogen

X 100% Molar mass of fertilizers

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9.2.3 The industrial process in manufacture of ammonia

1. Haber process is the industrial method of producing ammonia.

2. It needs direct combination of nitrogen and hydrogen under high pressure in the

presence of a catalyst, often iron.

3. Nitrogen gas used in Haber process is obtained from the frictional distillation of

liquid air.

4. Hydrogen gas used in Haber process can be obtained by two methods:

a) The reaction between steam and heated coke (carbon)

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C + H2O → CO + H2

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b) The reaction between steam and natural gas ( consisting mainly of

methane)

5. In the Haber process:

a) A mixture consisting of one volume of nitrogen gas and three volume of

hydrogen gas is compressed to a pressure between 200 – 500 atmospheres.

b) The gas mixture is passed through a catalyst of powdered iron at a

temperature of 450 - 550°C.

c) At this optimum temperature and pressure, ammonia gas is produced.

9.3 ALLOYS

9.3.1 Physical properties of pure metals

1.Pure metals have the following physical properties

a)Good conductor of electricity

b)Malleable

c)Ductile

d)High melting and boiling point

e)High density

2. Pure metals are weak and soft because the arrangement of atoms in pyre

metals make them ductile and malleable.

a) A pure metal contains atoms of the same size arranged in a regular and

organized closed-packed structure.

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CH4 + 2H2O → CO2 + 4H2

N2+ 3H2 → 2NH3

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b) Pure metals are soft because the orderly arrangement of atoms enables

the layers of atoms to slide over each other easily when an external force

is applied on them. This makes the matels ductile and metals can be

drawn to form long wires.

c) There are imperfections in the natural arrangements of metal

atoms. Empty space exist in the structures of pure metals. When

hammered or pressed, groups of metal atoms may slide into new

positions in the empty spaces. This makes metals malleable, able to be

made into different shapes or pressed into thin sheets.

3. The strong forces of attraction between metal atoms requires high energy to

overcome it. Hence, most metals have high melting points.

4.The close-packed arrangement of metal atoms results in the high density of

metals.

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Properties of metals

Good conductor of electricity

Ductile

High melting and boiling point

Malleable

High density

Figure 9.8 Properties of metals

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9.3.2 Meaning and purpose of making alloys

1. An alloy is a mixture of two or more elements with a certain composition

in which the major component is a metal.

2. in the process of alloying, one or more foreign elements are added to a

molten metal. When the alloy hardens, the positions of some of the metal

atoms are replaced by the atoms of foreign elements, which size may be

bigger or smaller than the original metal atoms.

3. In an alloy, these atoms of foreign elements disrupt the orderly

arrangement of the metal atoms and also fill up any empty space in the

metal crystal structure.

4. Hence, the layers of metal atoms are prevented from sliding over each

other easily. This makes the alloy harder and stronger, less ductile and less

malleable than its pure metals.

5. The properties of a pure metal are thus improved by making them into

alloys. There are three aims of alloying a pure metal:

a) To increase the hardness and strength of a metal

b) To prevent corrosion or rusting

c) To improve the appearance of the metal surface

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9.4 SYNTHETIC POLYMERS

9.4.1 The meaning of polymers

1. Polymers can be defined as large molecules composed of numerous smaller,

repeating units known as monomers which are joined by covalent bonds.

2. Polymerisation is the chemical process by which the monomers are joined

together to form the big molecule known as the polymers.

3. There are two types of polymerization process:

a)Addition polymerization

b)Condensation polymerization

4. A polymer is a very big molecule (macromolecule). Hence, the relative

molecular mass of a polymer is large.

5. The properties of polymer are different from its monomers.

6. Polymers can be divided into two types:

a)Naturally occurring polymers

1. This type of polymer exists in living things in nature like the plants and

animals.

2. Examples of naturally occuring polymers are:

a) Protein

b) Carbohydrate

c) Natural rubber

3. Naturally occuring polymers are formed by the joining of monomers by

polymerization.

4. Protein is formed by the joining of monomers known as amino acid.

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5. Carbohydrate is formed by the joining of monomers known as glucose.

6. Natural rubber is formed by the joining of monomers known as isoprene.

b)Synthetic polymers

1. This type of polymer are man-made by chemical process in the

laboratories.

2.The raw material for synthetic polymers are obtained frompetroleum.

3.The types of synthetic polymers include:

a) Plastics

b) Fibres

c) Elastomers

4. Examples of plastics are polythene(polyethylene),polyvinylchloride(PVC),

polypropene (polypropylene), polystyrene , Perspex and bakelite.

5.Polythene and PVC are produced by addition polymerization

6. Examples of synthetics fibres are nylon and terylene. They are produced

by condensation polymerization.

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9.4.2 Advantages of synthetic polymers

a) Strong and light

b) Cheap

c) Able to resist corrosion

d) Inert to chemical reactions

e) Easily moulded or shaped and be coloured

f) Can be made to have special properties

9.4.3 Environmental pollution caused by synthetic polymers

a) As most of polymers are non-biodegradable, they will not

decay like other organic garbage.

b) Burning of polymers release harmful and poisonous gases.

9.4.4 Methods to overcome the environmental pollution caused

by synthetic polymers

a) Reduce, reuse and recycle synthetic polymers

b) Develop biodegradable polymers

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9.5 GLASS AND CERAMICS

1. The main component of both glass and ceramic is silica or silicon dioxide, SiO2.

2. Both glass and ceramic have the same properties as follow

a) Hard and brittle

b) Inert to chemical reactions

c) Insulators or poor conductors of heat and electricity

d) Withstand compression but not stretching

e) Can be easily cleaned

f)Low cost of production

3. Differences between glass and cerement are, glass is transparent, while ceramic is

opaque. Ceramic can withstand a higher temperature than normal glass.

4. Types of glass are

a) Fused glass

It is consist mainly of silica or silicon dioxide

It has high heat resistance

b) Soda lime glass

It cannot withstand high temperatures

c) Borosilicate glass

It can withstand high temperature

d) Lead glass

High refractive index

5. Uses of improved glass for specific purpose

a) Photochromic glass

It is sensitive to light intensity

b) Conducting glass

It conducts electricity

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6. Ceramic is a manufactured substances made from clay, with the

main constituent of aluminosilicate with small quantity of sand and feldspar.

7. Superconductor is one improved ceramics for specific purposes.

Glass

1. Glass is made up from sand.

2. The major component of glass is SiO2.

3. There are four types of glass which are as follows:

Fused glass

Soda-lime glass

Borosilicate glass

Lead crystal glass

Name of glass PropertiesChemical

compositionExamples of uses

Fused glass

Very high softening

point (1700 °C)

hence, highly heat

resistant

Transparent to

ultraviolet and

infrared light

Difficult to be made

into different shapes

Does not crack when

temperature changes

(very low thermal

expansion coefficient)

Very resistant to

chemical reactions

SiO2 (99%)

Ba2 O 3 (1%)Telescope mirrors,

Lenses

Optical fibres

Laboratory glass

wares

Soda lime glassLow softening point Bottles

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(700 °C), hence, does

not withstand heating

Breaks easily

Cracks easily with

sudden temperature

changes (high

coefficient of

expansion)

Less resistant to

chemical reactions

Easy to be made into

different shapes

SiO2 (70%)

Na2O (15%)

CaO (3%)

Others (5%)

Windowpanes

Light bulbs

Mirrors

Bowls

( The most widely

used type of glass)

Borosilicate

glass

High softening point

(800°C). Thus it is

heat resistant

Does not crack easily

with sudden

temperature changes

Transparent to

ultraviolet light

More resistant to

chemical reactions

Does not break easily

SiO2 (80%)

Ba2 O 3 (15%)

Na2O (3%)

Al 2 O 3

Laboratory apparatus

Cooking utensils

Electrical tubes

Glass pipelines

Lead crystal

glass

Low softening point

(600 °C)

High density

High refractive index

Reflects light rays

SiO2 (55%)

PbO( 30%)

K2O (10%)

Na2O ( 3%)

Al2 O 3 ( 2%)

Decorative items

Crystal glass-

wares

Lens

Prisms

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and appears spar

kling

Chandeliers

Ceramics

1. Ceramic is a manufactured substance made from clay that is dried and then

baked in a kiln at high temperature.

2. The main constituent of clay is aluminosilicate, (which consist of aluminium

oxide and silicon dioxide) with small quantities of sand and feldspar.

3. Kaolinite is an example of high

4. Red clay contains iron (III) oxide which gives the red colour .

5. General uses ceramics are as follows of :

very hard and strong but brittle

inert to chemical reaction

has a very high melting point

good electric and heat insulator

able to withstand compression

9.6 COMPOSITE MATERIAL

1. A composite material is a structural material formed by

combining two or more materials with different physical properties, producing a

complex mixture.

2. The composite material produced will have different properties

far more superior to the original materials.

3. The composite material produced are harder, stronger, lighter,

more resistant to heat and corrosion and also for specific purposes.

4. When composite material is formed, the weakness of the

components will not exist anymore.

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Composite material Component Properties of

component

Properties of

composite

Reinforced concrete

Concrete Hard but brittle,

With low tensile

strength

Stronger, higher

tensile strength, not

so brittle, does not

corrode easily, can

withstand higher

applied forces and

loads, relatively

cheaper

Steel Hard with high

tensile strength but

expensive and can

corrode

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Fibre optics

Glass of low

refractive index

Transparent, does

not reflect light

rays.

Reflect light rays

and allow light rays

to travel along the

fibreGlass of high

refractive index

Heavy, strong but

brittle and non-

flexible

Fibreglass

Glass Heavy, strong but

brittle and non-

flexible

Light, strong, tough,

resilient and

flexible, with high

tensile strength and

not flammable

Polyester plastic Light, flexible,

elastic but weak and

inflammable

Photochromic glass

Glass Transparent and not

sensitive to light

Sensitive to light:

darkness when light

intensity is high,

becomes clear when

light intensity is low

Silver chloride, or

silver bromide

Sensitive to light

Figure 9.9 Composite material and their new properties

CONCLUSION

We must appreciate these various synthetic industrial materials. One of the way is by

doing continuous research and development ( R & D ) to produce better materials used to

improve our standard of living. As we live in a changing world, our society is getting

more complex. New materials are required to overcome new challenges and problems we

face in our daily lives. Synthetic material are developed constantly due to the limitation

and shortage of natural materials. New technological developments are used by scientists

to make new discoveries.

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New materials for clothing, shelter, tools and communication to improve our daily

life are developed continuously for the well-being of mankind. New needs and new

problem will stimulate the development of new synthetic materials. For example, the new

use of plastic composite material will replace metal in the making of a stronger and

lighter car body. This will save fuel and improve speed. Plastic composite materials may

one day used to make organs for organ transplant in human bodies. This will become

necessity with the shortage of human organ donors.

The understanding of the interaction between different chemicals is important for

both the development of new synthetic materials and the disposal of such synthetic

materials as waste. A responsible and systemic method of handling the waste of synthetic

materials and their by-product is important to prevent environmental pollution. The

recycling and development of environmental friendly synthetic material should be

enforced.

REFERENCES

1. Tan Yin Toon, Loh Wai Leng, Tan On Tin, 2008, SUCCESS

Chemistry SPM, Oxford Fajar Sdn.Bhd.

2. Website http://www.answers.com

3. www.wikipedia.com/manufactured substances in industry

4. Longman Essential Chemistry SPM – M/S 283

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