folio chemistry f4 ( manufactured substances in industry )

7/29/2019 Folio Chemistry F4 ( Manufactured Substances in Industry )

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NAME :

CLASS :

TEACHER:


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CONTENT

Introduction

Sulphuric acid

9.1.1 Properties of sulphuric acid9.1.2 The uses of sulphuric acid9.1.3 The industrial process in manufacture of sulphuric acid9.1.4 Environmental pollution by sulphuric acid

Ammonia and its salt

9.2.1 Properties of ammonia9.2.2 The uses of ammonia9.2.3 The industrial process in manufacture of ammonia

Alloys

9.3.1 Physical properties of pure metas9.3.2 Meaning and purpose of making alloys9.4 Synthetic polymers9.4.1 The meaning and types of polymers9.4.2 Advantages of synthetic polymers9.4.3 Environmental pollution caused by synthetic polymers9.4.4 Methods to overcome the environmental pollution

caused by synthetic polymers9.5 Glass and ceramics9.6 Composite material

Conclusion

References


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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 beenough 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 scientistproduces 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 theprevious chapters.


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9.1.1 Properties of sulphuric acid

1.Sulphuric acid is a strong mineral acid.

2.Its molecular formula is H2 SO4.

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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Diagram 9.1 shows the Properties of Sulphuric Acid

PROPERTIES

OF

SULPHURIC

ACID

DIPROTIC

ACID

DENSE

OILYLIQUID

HIGHLY

COROSSIVE

NON -

VOLATILE

ACID

SOLUBLEIN WATER


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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

2) To manufacture detergents

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

neutralized with sodium hydroxide to produce detergents.

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:

- As a strong acid

- As a drying or dehydrating agent

- As an oxidizing agent

- As a sulphonating agent

- As a catalyst


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Diagram 9.2 shows the Uses of Sulphuric Acid


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9.1.3 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.

Sulphur Sulphur dioxide Sulphur trioxide Sulphuric acid

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.

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

a) The presence of a vanadium(V) oxide as a catalyst.b) A temperature of between 450C to 550C.

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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Contact Process

A brief summary of the Contact Process:

- Solid sulphur, S(s), is burned in air to form sulphur dioxide gas.

- The gases are mixed with more air then cleaned by electrostatic precipitation toremove any particulate matter.

- The mixture of sulphur dioxide and air is heated to 450 degree Celcius and subjectedto a pressure of 101.3 - 202.6 kPa (1 -2 atmospheres) in the presence of a vanadiumcatalyst (vanadium(V) oxide) to produce sulphur trioxide, with a yield of 98%.

- Any unreacted gases from the above reaction are recycled back into the abovereaction.

- Sulphur trioxide is dissolved in 98% (18M) sulphuric acid to produce disulphuric acid orpyrosulphuric acid, also known as fuming sulphuric acid or oleum.

- Water is then added to the oleum to produce 98% of sulphuric acid.
http://2.bp.blogspot.com/_Red3kx4ddLw/TLKLafFdV-I/AAAAAAAAAQw/l-0GhuLDKjc/s1600/contactflow.gif


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9.1.4 Environmental pollution by sulphuric acid

1. Sulphur dioxide is the main byproduct produced when sulphur-containing fuelssuch 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 plantsiii. 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:

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


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9.2AMMONIA AND ITS SALT

9.2.1 Properties of ammonia

1. A colourless, 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 producewhite fumes of ammonium chloride.

NH3 + HCl NH4Cl

7. Ammonia is alkaline in property and reacts with dilute acids inneutralization to produce salts. For examples:

NH3 + HNO3 NH4NO3

2NH3 + H2SO4 (NH4)2 SO4

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

and Ca 2+ ion) forming metal hydroxides precipitate.

Fe 3+ + 3OH Fe (OH) 3

Mg 2+ + 2OH Mg (OH) 2

9. Some metal hydroxides such as zinc hydroxide and copper (II) hydroxidedissolves in excess aqueous ammonia to form complexes.

Zn(OH)2 + 4NH3 [Zn(NH3)4] 2+ + 2OH

Cu(OH)2 + 4NH3 [Cu(NH3)4] 2+ + 2OH


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Figure 9.3 A molecule of ammonia.

Diagram 9.4 shows the Properties of Ammonia

Properties

of

Ammonia

extremely

soluble inwater

pungent

smell

weak

alkaline

colourless


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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 percentageof 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:

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)

C + H20 CO + H2

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

methane)

CH4 + 2H2O CO2 + 4H2

5. In the Haber process:

A mixture consisting of one volume of nitrogen gas and three volume ofhydrogen gas is compressed to a pressure between 200500

atmospheres. The gas mixture is passed through a catalyst of powdered iron at a

temperature of 450 - 550C. At this optimum temperature and pressure, ammonia gas is produced.

N2+ 3H2 2NH3


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Making of Ammonia

Ammonia is manufactured by combining nitrogen and hydrogen in an important industrial

process called the Haber process. The reaction is reversible and the production of ammonia is

exothermic.

Nitrogen gas is obtained from the fractional distillation of liquid air.

Hydrogen gas is obtained through the reaction between natural gas and steam.

Nitrogen and hydrogen are mixed in the ratio of 1 : 3
http://1.bp.blogspot.com/-2G6aYqyBaNg/TpcF8EwuzEI/AAAAAAAAAyU/bgGVVuiYdJI/s1600/habereq.gifhttp://1.bp.blogspot.com/-2G6aYqyBaNg/TpcF8EwuzEI/AAAAAAAAAyU/bgGVVuiYdJI/s1600/habereq.gif


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9.3 ALLOYS

9.3.1 Physical properties of pure metals

1. Pure metals have the following physical properties

a) Good conductor of electricityb) Malleablec) Ductiled) High melting and boiling pointe) High density

2. Pure metals are weak and soft because the arrangement of atoms in pure metals make them

ductile and malleable.

a) A pure metal contains atoms of the same size arranged in a regular and organizedclosed- packed structure.

b) Pure metals are soft because the orderly arrangement of atom enables the layers ofatoms to slide over each other easily when an external force is applied on them. This

makes the metals ductile and can be drawn to form long wires.

c) There are imperfections in the natural arrangements of metal atoms. Empty spaceexist 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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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 othereasily. 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 metalb) To prevent corrosion or rusting

c) To improve the appearance of the metal surface


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An alloy is a mixture of two or more elements with a certain fixed composition in whichmetal is the major component.

The making of alloy is:

To increase the strength and hardness of a pure metal.

To prevent corrosion.

To improve the appearance of a pure metal.

Pure Metal

Pure metal is made up of one type of atoms that are in same size.

Therefore, when a force is applied, the layers of atoms can slide

over one another. Thus, metals are ductile or can be stretched.

There are some empty spaces in between the pure metal atoms.

When a metal is knocked or pressed, groups of atoms may slide

and then settle into new positions. Thus, metals are malleable or

can be shaped.

Examples of Alloy


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Alloy

Some of the spaces between the metal atoms are filled up by

the foreign atoms which may be bigger or smaller than the

original metal atoms.The presence of foreign atoms disrupts the orderly

arrangement or the pure metal.

The layers of metal atoms are prevented from sliding over one

another easily. This makes alloys stronger and harder than

pure metals.

Examples of alloy

Alloy Composition

Steel 99 % iron + 1 % carbon

Stainless steel 74 % iron + 18 % chromium + 8 %

nickel

Bronze 90 % copper + 10 % tin

Brass 70 % copper + 30 % zinc

Magnalium 70 % aluminium + 30 % magnesium

Duralumin 95 % aluminium + 4 % copper +

1 % magnesium

Pewter 97 % tin + 3 % lead and antimony

Solder 50 % tin + 50 % lead

cupronickel 25 % copper + 75 % nickel
http://4.bp.blogspot.com/-KeroPbKNXPM/TrFnyUDlhPI/AAAAAAAAA3o/leWGjLoHDdY/s1600/alloy.gifhttp://4.bp.blogspot.com/-KeroPbKNXPM/TrFnyUDlhPI/AAAAAAAAA3o/leWGjLoHDdY/s1600/alloy.gif


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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 polymerizationb) 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.


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6. Polymers can be divided into two types:

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.

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.

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

Diagram 9.5 shows the Advantages of Synthetic Polymers

Advantages of

synthetic

polymers

strong and

light

Easily

moulded orshaped and

be coloured

can be made

to have

special

properties

inert to

chemical

reaction

able to resist

corrosion

cheap


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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 pollutioncaused 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 brittleb) Inert to chemical reactionsc) Insulators or poor conductors of heat and electricityd) Withstand compression but not stretchinge) Can be easily cleanedf) 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

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.


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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 Properties ChemicalComposition

Examples ofuses

Fused glassVery 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

(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%)

Bottles

Windowpanes

Light bulbsMirrors

Bowls

( The most widely

used type of glass)


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Name of Glass Properties Chemical

Composition

Examples of

usesBorosilicateglass

High softening point

(800C). 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 crystalglass

Low softening point

(600 C).

High density.

High refractive

index.

Reflects light rays

and appears

sparkling.

SiO2 (55%)

PbO( 30%)

K2O (10%)

Na2O ( 3%)

Al2 O 3 ( 2%)

Decorative items

Crystal glassware

Lens

Prisms

Chandeliers


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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


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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.

Composite

Materials

Component Properties of

Component

Properties of

materials

Reinforcedconcrete

Concrete Hard but brittle,With low tensile

strength

Stronger, higher

tensile strength,

not so brittle, doesnot corrode easily,

can withstand higher

applied forces and

loads, relatively

cheaper

Steel Hard with hightensile strength but

expensive and can

corrode

Fibre optics Glass of low

refractive indexTransparent, does

not reflect light

rays.

Reflect light rays

and allow light to

travel along the fibre.

Glass of high

refractive index

Heavy, strong but

brittle and non-

flexible

Fibreglass Glass Heavy, strong butbrittle and non-

flexible

Light, strong, tough,

resilient and flexible,

with high tensile

strength and not

flammable.Polyester plastic Light, flexible,elastic but weak andinflammable

Photochromicglass

Glass Transparent and notsensitive to light.

Sensitive to light:

darkness when light

intensity is high,

becomes clear whenlight intensity.

Silver chloride, or

silver bromideSensitive to light


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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 morecomplex. New materials are required toovercome 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 newdiscoveries.

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

our daily life are developed continuously for the well-being of mankind. Newneeds and new problem will stimulate the development of new synthetic

materials. For example, the new use of plastic composite material will replacemetal 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 disposalof 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.

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