Manufactured Substances in Industry

(1)

The

Uses

of

Sulphuric

Acid

in

Daily life

Manufacture

fertiliser

Manufacture

detergents

Manufacture

pesticides

Manufacture synthetic

fibres

Manufacture paint

pigments

As the electrolyte in

lead-acid accumulators

T

To remove metal

o remove metal oxides

oxides

from metal surface

SULPHURIC ACID

(2)

Environmental Pollution by Sulphur Dioxide

Pollution of

Sulphur Dioxide

Burning of fossil fuels

Fossil fuels such as petroleum.

It contain sulphur. Sulphur dioxide is produced when fossil fuels are burned

Affects the

respiratory system

Sulphur is a poisonous and acidic gas.

It causes coughing, chest pains, shortness of

breath, lung diseases and bronchitis

Burning of sulphur

in industrial area

The contact process and the burning of coals or fuels produce high

sulphur dioxide content

Affect of acid rain

Sulphur dioxide gas dissolve in atmospheric water to produce sulphurous acid, H₂SO₃and sulphuric acid,H₂SO₄. These acids causes acid rain.

(3)

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• Burning of sulphur in dry air in the furnace

• Burning of metal sulphides such as zinc sulphide also

produces sulphur dioxide.

• The sulphur dioxide is mixed with excess air. The mixture

is then died and purified to remove impurities such as arsenic compounds.

• Arsenic compounds found in sulphur will poison the

catalyst in the converter , make the catalyst ineffective Production of sulphur dioxide gas, SO₂

S(s) + O₂(g) SO₂(g)

• Mixture of sulphur dioxide and excess dry oxygen is passed

through a converter.

• Sulphur dioxide is oxidised to sulphur trioxide.

• 98%conversion from sulphur dioxide to sulphur trioxide is

achieved under condition:

i. Catalyst : vanadium (V) oxide,V2O5 ii. Pressure: 1 atmosphere

iii. Temperature:450°C

_–

550°C

Conversion of sulphur dioxide to sulphur trioxide, SO₃

• In the absorber, sulphur trioxide is dissolve in

concentrated sulphuric acid to produce oleum , H₂S₂O₇ a viscous liquid.

• Oleum is then diluted with equal volume of water to

produce concentrated H₂SO₄(98%) Production of sulphuric acid

Sulphur Sulphur Dioxide, SO₂ Oleum, H₂S₂O₇ Sulphurtrioxide , SO₃ Sulphuric acid , H₂SO₄

(5)

AMMONIA AND ITS SALT

Nitric acid

Detergents

Prevent coagulation of latex

Paint and colouring

Synthetic fabric

Explosive (TNT)

Synthetic fertiliser

(6)

The manufacture of nitrogenous fertiliser

Ammonia reacts with sulphuric acid through neutralisation to produce ammonium sulphate

2NH₃(aq) + H₂SO₄(aq) (NH₄)₂SO₄(aq)

Ammonia reacts with nitric acid through neutralisation to produce ammonium nitrate

NH₃(aq) + HNO₃(aq) NH₄NO₃(aq)

Ammonia reacts with carbon dioxide at temperature of 200°C and pressure of 200 atmosphere to produce urea

2NH₃(g) + CO₂(g) CO(NH₂)₂(s)+H₂O(l)

Ostwald process

• In the Ostwald process, ammonia is concerted into nitric

acid by three stages

Ammonia is oxidised to

nitrogen monoxide gas in the presence of platinum as catalyst

4NH₃(g) +5O₂(g) 4NO(g) + 6H₂O(g)

Stage 1 Nitrogen monoxide is further oxidised to nitrogen dioxide 2NO(g) + O₂(g) 2NO₂(g) Stage 2 Nitrogen dioxide is dissolve in water to produce nitric acid

2NO(g) + H₂O(l) HNO₃(aq) + HNO₂(aq)

Stage 3 Very soluble in water Change red litmus paper blue Colourless and pungent gas

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The Industrial Process in the Manufacture of Ammonia

The nitrogen and hydrogen gases are combined

The gases are compressed at 200 atmosphere, 450°C

The gases pass through the converter. Iron is used as a catalyst

The Gases are cooled down until the ammonia condenses

Ammonium fertilisers

The ammonium stored as a

liquid under pressure. The excess hydrogen and

nitrogen gases are recycled to continue the reaction

• Nitrogen is absorbed by plants in the form of

soluble nitrates, NO3- _{to produce protein}

• Ammonium fertilisers are used to replace elements

in soil used up by plants.

• Ammonium ions, NH₄+ can be converted into

nitrate ions by bacteria living in the soil.

• The fertiliser with higher percentage of nitrogen is

more effective and this can be determined as below:

Percentage of nitrogen by weight

=

  

(8)

Ductile • Ductile is the ability to be stretched Malleable • Malleable is the ability of a metal to be shape

High melting and boiling point

• The strong force of

attraction between metal atoms requires high

energy to overcome it. Hence, metal have high melting points.

High density

• In solid state, the atoms

in pure metal are orderly arrange and closely

packed, causes pure metal to have high density

Good conductors

Alloys

Meaning and purpose of making alloys

• Pure metal such iron

and tin are easily corrode in polluted , damp or acidic air

• Alloying can prevent

metals from corrosion due to the formation of oxide layer on the surface of the metal To prevent corrosion

• Adding the little carbon to iron

metal produces steel which is very hard alloy of iron

• Adding magnesium to

aluminium metal produces an alloy called Magnalium

• Adding tin copper metal

produces bronze. Bronze is an alloy harder than tin and

copper

• Pure metal can rust and tarnish easily

because of the formation of metal oxides

• Alloying can maintain the lustre on the

surface of metal

To increase the strength and hardness

To improve the appearance

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Stainless steel

Manganese steel

(Hadfield steel)

Bronze

Cupro-nickel

brass

Duralumin

steel

75% copper + 25% nickel • Hard-wearing

• Attractive silver colour

and shiny

• Does not rust

75% copper + 25% zinc

• Harder than copper • Does not corrode • Shiny and strong • malleable

74% iron +18% nickel

• Does not rust

• Hard

• Strong

• Withstand corrosion better

than carbon steel

99.5% iron + 0.5% carbon

• Very hard • strong

97% tin + 3%

antimony and copper

• Shiny and

attractive appearance

• Does not corrode • Easily cast

95% aluminium + 3%

copper + 1% mangan + 1% manganese

• Hard

• Does not corrode • Light but strong

85% iron + 13.8% manganese + 1.2% carbon

• Very hard

88% copper + 12% tin

• Harder than brass • Does not corrode • Does not rust • Sonorous

• Attractive appearance • Easily shaped

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Synthetic polymers

Natural polymers

protein

carbohydrates

_{Natural rubber}

• Monomer amino acid

e.g. in muscles, skin, silk, hairs, wool and furs

• Monomer glucose

e.g. in starch and cellulose

• Monomer isoprene

(2-methylbuta-1,3-diene e.g.in latex

Synthetic polymers and their uses

Styrene-butadiene rubber(SBR) (monomers: styrene & butadiene

Neoprene (monomers : chloroprene) Butyl rubber(monomers: isoprene)

Synthetic rubber

Nylon (monomers : diamine and dicarboxylic acid)

Terylene (monomers: diol and dicarboxylic acid

thermoplastic

Synthetic fibres

Polyvinyl chloride (PVC) (monomers: chlorothene)

Polythene (monomer : ethene) polystyrene (monomers:

phenylethene)

Polypropene (monomers : propene)

Prespex (monomers : methyl metacrylate)

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Issues on the use of synthetic polymer in daily life

Strong and light

Can be made to have special properties

cheap

Easily moulded or shaped and be coloured Able to resist corrosion

Effect of disposal of synthetic polymer

Air pollution:

caused by burning of plastic

• E.g. burning of PVC will produce dioxin. Dioxin

will destroy human immune system,

reproductive system and nervous system

Soil pollution:

• Plastic thrown on land lift up our

living spaces

• Destroys the beauty of

environment

• Plastic also causes the soil not

suitable for planting because plastics inhibit the growth of root

Water pollution:

• Plastics will stop the flow of river

water and drains. This will cause flash floods.

• Plastics also causes the death or

marine organisms if they mistaken the plastics as food

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Recycle

biodegradable

Use own plastic products

reuse

replacement

convertion

• Take part in plastic

recycling activities by sending recyclable products to recycle centers • Buy recyclable or biodegradable products with little packaging

• Use biodegradable

plastics which can be decomposed by

microorganisms

• Reuse goods that are

usually thrown away. For example, plastic containers and bags can be made into decorative item

• Bring our food

container, shopping bag and basket

• Convert used products

made from synthetic polymers into something useful. For example, used tyres can be converted into playground

equipment.

• Use others materials to

replace plastic

products. For example, use paper bags instead of plastic bags

(13)

Glass and ceramics

Impermeable to

liquid

Electrical

insulator

Heart insulators

_{Chemically inert}

Hard but brittle

Transparent

Properties, composition and uses of different types of glass

Name of glass

Properties

Example of uses

Fuse glass(99% SiO₂ + 1% B₂O₃)

• High melting point (1700°C) • Resistant to thermal shock

• High temperature and chemical

durability

• Transparent to ultraviolet and

infrared light

• Difficult to be made into

different shapes

• Telescope mirrors

• Laboratory glass wares • Lenses

• Optical fibres

• Arc tubes in lamps

Soda-lime glass (70%SiO₂ + 15% Na₂O + 10% CaO +

5% others)

• Low melting point( 7000°C) • Does not withstand heat • Cracks easily with sudden

temperature chances

• Easy to mould and shape • Transparent to visible light • Good chemical durability • High thermal expansion

coefficient

• Bottles

• Window panes • Flat glass

• Light bubbles

• Industrial and art objects

Borosilicate glass (80% glass SiO₂+ 15% B₂O₃+ 3% Na₂O

+ 1% Al₂O₃)

• Quite high melting point (800°C) • Does not crack easily with

sudden change in temperature

• Breaks easily

• More resistant to chemical

attack

• Does not break easily

• Laboratory apparatus • Cooking utensils

• Electrical tubes • Glass pipelines

Lead glass (55% SiO₂ + 30% PbO + 10% K₂O + 3% Na₂O + 2%

Al₂O₃

• Low melting point (600°C) • High refractive index

• High density • Reflects light rays

• Crystals • Prism • Tableware • Art objects

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Extremely hard and strong but brittle

Able t withstand or resists compression

Good insulators of electric and heat Inert to chemicals

(withstand corrosion) Has a very high

melting point

The uses of improved glass and ceramics for specific purpose

• A pure glass thread that conducts light • The fibre can transmit massage

modulated onto light waves

• Used in medical instruments, local area

networks (LAN) and control board displays

• Fibre optic cables are much lighter and

thinner than the metal cables.

• It can carry mode data than metal cables

• A type of glass that can conduct

electricity

• Produced by embedding a thin layer

of conducting material in glass

• Adding a layer of indium tin(IV) oxide

(ITO) acts as an electrical conductor. Used in the making of LCD

• Another type is produced embedding

thin gold threads in glass to conduct electric current and produce heat

• Used in windows of aircraft

• Rearrange its atoms into regular

patterns by heating glass to form strong materials

• It can withstand high temperature,

chemical attacks, better mechanical strength and better electrical insulators compared to normal glass

• Used in tiles, cookware, rockets and

engine blocks

• Superconductors can conducts electricity at low temperature without

resistance and without loss of electrical energy as heat

• A type of glass sensitive to light

intensity

• The glass darken when exposed to

sunlight but becomes clear when light intensity decrease

• This is produced when dispersion of

silver bromide, AgBr or silver chloride, AgCl and copper (I) chloride is added to normal glass

• Used in windows, sunglasses and

(15)

Appreciating various synthetic industrial

• Sources of materials are limited so

we should not waste them and use them carefully

• We should minimise the use of

non-biodegradable synthetic materials or make them biodegradable

• A responsible and systematic

method of handling should be practiced

• The understanding of the interaction among materials enables new materials to be

developed

• New materials is created to improve our daily life

Handling synthetic

material and their wastes

The importance of doing

research and development

• New needs and new problems will

stimulate the development of new synthetic materials

• For example:

 New plastic composite

materials will replace metal to make a stronger and lighter car body

 New superconductor made

from composite materials are developed.

Justify the importance of

synthetic materials in daily life

(16)

Composite material

Composite materials

component Properties of component

Properties of composite

Uses of composite

Reinforced concrete concrete • Hard but brittle • Low tensile

strength

• Stronger • Higher tensile

strength

• Does not corrode

easily

• Cheaper

• Can be moulded

into any shape

• Can withstand very

high apply forces

• Can support very

heavy loads • Construction of roads • Rocket launching pads • High-rise buildings steel • Strong in tensile

strength • Expensive • Can corrode Superconductor • Copper (II)oxide • Yttrium oxide • Barium oxide • Insulators of electricity • Conducts electricity without resistance when cooled by liquid nitrogen • Magnetically levitated train • Transformers • Electric cable • amplifier

Photochromic glass • glass • Transparent • Not sensitive to

light

• Reduce refraction of

light

• Control the amount

of light passes through it automatically

• Has the ability to

change colour and become darker wen exposed to ultraviolet light • Information display panels • Light detector device • Car windshields • Optical lens • Silver chloride or silver bromide • Sensitive to light

Fibre optics • Glass with

low refraction index

• Transparent • Does not reflect

light rays

• Low material cost • Reflect light rays and

allow to travel along the fibre

• Can transmit

electronic data or signals, voice and images in the form of light along the fine glass tubes at great speeds

• Transmit data

using light wave in telecommunicati on • Glass with higher refractive index

Fibre glass • glass • High density • Strong but brittle • Non-flexible

• High tensile strength • Moulded and shaped • Inert to chemicals • Light strong • Tough • Not inflammable • Impermeable to water Resilient • Car bodies • Helmets • Skies • Rackets • furniture • Polyester plastic • Light • Flexible • Inflammable • Elastic but weak