Chemistry Form 4 Chapter 9
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Transcript of Chemistry Form 4 Chapter 9
CHAPTER 9 :
MANUFACTURED
SUBSTANCES IN
INDUSTRY
NAME:PAVITRAN A/L PUPATHE
CLASS: 4EN
SCHOOL: SMK HORLEY METHODIST
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 7
9.1.4 Environmental pollution by sulphuric acid 10
9.2 Ammonia and its salt
9.2.1 Properties of ammonia 11
9.2.2 The uses of ammonia 12
9.2.3 The industrial process in manufacture of ammonia 13
9.3 Alloys
9.3.1 Physical properties of pure metals 14
9.3.2 Meaning and purpose of making alloys 15
9.4 Synthetic polymers
9.4.1 The meaning and types of polymers 16
9.4.2 Advantages of synthetic polymers 17
9.4.3 Environmental pollution caused by synthetic polymers 17
9.4.4 Methods to overcome the environmental pollution caused
by synthetic polymers
18
9.5 Glass and ceramics 18
9.6 Composite material 22
Conclusion 24
References 25
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
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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 knowledge 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.
9.1 SULPHURIC ACID
9.1.1 Properties of sulphuric acid
3Figure 9.1 A molecule 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.
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:
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Properties of sulphuric acid
Non-volatileacid
Diprotic acid
Soluble in water
Highly corrosive
Oilyliquid
Viscous colourless
liquid
Dense
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. 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
5
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
As an acid2%
Fertilisers32%
Other chemicals
16%
Paint pigment15%
Detergents12%
As an electrolyte
10%
Synthetic fibres9%
Metal cleaning2% Dyes
2%
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
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
Figure 9.4 Uses of sulphuric acid in industry
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.
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.
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Sulphur → Sulphur dioxide → Sulphur trioxide → Sulphuric acid I II III
S + O2 → SO2
2ZnS + 3O2 → 2SO2 + 2ZnO
5. Stage II: Conversion of sulphur dioxide to sulphur trioxide SO3.
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
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
Figure 9.5 Flowchart of Contact process
9.1.4 Environmental pollution by sulphuric acid
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Sulphur or metal sulphide
Sulphur dioxide, SO2
Sulphur trioxide, SO3
Oleum, H2S2O7
Concentrated sulphuric acid H2SO4
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:
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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9.2 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.
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.
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NH3 + HCl → NH4Cl
2NH3 + H2SO4 → (NH4) 2SO4
NH3 + HNO 3 → NH4NO 3
Fe3+ + 3OH− → Fe(OH) 3
Brown precipitate
Mg2+ + 2OH− → Mg(OH) 2
White precipitate
Figure 9.6 A molecule of ammonia.
Properties of ammonia
Colorless Pungentsmell
Extremely soluble in
waterWeakalkali
9. Some metal hydroxides such as zinc hydroxide and copper (II) hydroxide
dissolves in excess aqueous ammonia to form complexes.
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.
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Zn(OH)2 + 4NH3→ [Zn(NH3)4] 2++ 2OH−
Cu(OH)2 + 4NH3→ [Cu(NH3)4] 2+ + 2OH
−
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:
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)
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.
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C + H2O → CO + H2
CH4 + 2H2O → CO2 + 4H2
N2+ 3H2 → 2NH3
Mass of nitrogen
X 100% Molar mass of fertilizers
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.
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
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.
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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
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
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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.
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
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
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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.
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 glassVery high softening
point (1700 °C)
hence, highly heat
SiO2 (99%)
Ba2 O 3 (1%)
Telescope mirrors,
Lenses
Optical fibres
19
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
Laboratory glass
wares
Soda lime glass
Low 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 bulbs
Mirrors
Bowls
( The most widely
used type of glass)
Borosilicate
glassHigh softening point
(800°C). Thus it is
heat resistant
SiO2 (80%)
Ba2 O 3 (15%)
Na2O (3%)
Laboratory apparatus
Cooking utensils
Electrical tubes
Glass pipelines
20
Does not crack easily
with sudden
temperature changes
Transparent to
ultraviolet light
More resistant to
chemical reactions
Does not break easily
Al 2 O 3
Lead crystal
glass
Low softening point
(600 °C)
High density
High refractive index
Reflects light rays
and appears spar
kling
SiO2 (55%)
PbO( 30%)
K2O (10%)
Na2O ( 3%)
Al2 O 3 ( 2%)
Decorative items
Crystal glass-
wares
Lens
Prisms
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
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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.
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
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
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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.
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.
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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
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