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Chemis Folio

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 1) Polymers are long chains of molecules made from combinations of many small molecules. 2) Small molecules that combine to form polymers are called monomers. 3) Polymerisation is a process of combining monomers to form a long of molecules. 4) Polymers can be divided into two types: a) natural polymer b) synthetic polymer 
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1)  Polymers are long chains of molecules made from

combinations of many small molecules.

2)  Small molecules that combine to form polymers are called

monomers.

3) Polymerisation is a process of combining monomers to forma long of molecules.

4)  Polymers can be divided into two types:

a)  natural polymer 

b)  synthetic polymer 

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Natural polymer 

1)  A natural polymer is a polymer that occurs naturally.

2) Natural polymers are normally made by living organisms.

Natural polymer Monomers (small molecules)

Rubber isoprene

cellulose Glucose

Starch Glucose

Protein Amino acid

Fat Fatty acids and glycerol

Nuclei acid nucleotides

Examples of natural polymers and their monomers

Synthetic polymers

1)  Synthetic (artificial) polymers are man-made polymers

that are produced from chemical compounds through

polymerization.

2)  Plastic, synthetic fibres and synthetic rubbers are

three examples of synthetic polymers

3)  Thare are two types polymerization:

a)  addition polymerization

b)  Condensation polymerization

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Addition polymerization

1)  Unsaturated monomers that contain double bonds

between two carbon atoms undergo addition

polymerization.

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2)  Monomers undergo addition polymerisation as shown

in figure 9.14.

3)  If the structure of a monomer is known, the structural

formula of its synthetic polymer can be determined as

shown below:

a)  step 1

Write the symbol for two carbon atoms with double

bonds in the middle. ¶Push· the atom or molecules thet is

tied to the two carbon atoms above the two carbonatoms.

b)  step 2

Change or ¶open· the double bond into single covalent

bonds and draw brackets.

c)  step 3

Write the letter ¶n· at the bottom right-hand corner of the

molecule.

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4)  The monomers in a polymer can be determined. The

followingguidelines are given to help you to determine

the monomers in a polymer, formed through the

addition polymerisation.

a)  step 1

Determine the position of the two consecutive carbon

atoms (small repeating units) in the structure of a

polymer molecule.

b)  step 2

Change or ¶close· the single bond into a double bond.

Condensation polymerisation

Small molecules such as water, H2O, and ammonia,N

H3, arereleased in condensation polymerisation.

Monomer Polymer 

(a) Adpic acid and

hexanediamine

nylon

(b) 1, 2-dicarboxylbenzene and

ethane-1, 2-diol

terylene

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Uses of synthetic polymers

1) Synthetic polymers are used widely in daily life.

Type of polymer Use

Polythene Make buckets, plastic bags,

raincoats, films, bowls and

rubbish bins

Polyvinyl chloride (PVC) Make water pipes, electric

cables, mats, vinyl records and

clothes hangers

Polypropene Make ropes,bottles, chairs,drink cans and carpets

Perspex Make car windscreens, airplane

window panes and spectacle

lenses (optical instruments)

Nylon Make ropes, curtains, stockings

and clothes

Polysyrene Make packing boxes, buttons

and noticeboards

Terylene Make textile items such asclothes and cloths

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3)  Synthetic polyumers such as plastic, synthetic fibers and

synthetic rubber have been used to replace various naturalitems such as cotton, silk, glass, metal, timber and rock

Natural compounds that have

been replaced by synthetic

polymers

The advantages of synthetic

polymers compared to natural

compounds

Cotton and silk Stronger, more durable,

withstands dirt, and does not

wrinkle easily

Paper Waterproof, does not wrinkle or tear easily

Timber Does not rot easily

Metal Lighter, does not corrode

easily, more easily forged and

colured

Glass and ceramics Does not break easily

Marble (rock) cheaper 

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Effects of the disposal of items made from synthetic polymers

on the environment.

1)  Synthetic polymers are not biodegradable (not

decomposed by microorganisms).2)  The careless disposal of items made from

synthetic polymers such as plastic causes

environmental pollution.

3)  The effects of burning and careless disposal of 

items made from synthetic polymers on the

environment are as follows:

a)  Burning of synthetic polymers

y  releases pollutants that endanger health such

as smoke, gases that are smelly, poisonous andcorrosive such as sulphur dioxide, pollutants

that cause acid rain and the greenhouse effect.

b)  Careless disposal of synthetic polymers

y  spoils the beauty of the environment

y  causes flash floods during heavy rainfall

y  endangers marine life like tutles that

accidentally eat polymers such as plastic as its

food.

4) the best way to manage used items made fromsynthetic polymers is to recycle them.

5)  Plastics that are biodegradable can be used

instead to reduce environmental pollution.

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Types, composition, characteristics and uses of 

glass

1)  The main component of glass is silica or 

silicon dioxide, Si02, which is obtained

from sand.

2)  The main characteristics of glass are:

(a) brittle

(b) hard

(c) chemically inert

(d) transparent

(e) not permeable to gas and liquid (fluid)

(f)  does not conduct electricity

(g) heat insulator 

3)  The most simple glass is the fused silica

glass. This glass mainly condiyions, Sio2.

4)  Most of the glasses are produced by

mixing molten silica, SiO2, with other 

compounds.

5)  Glass can be recycled. Glass can also be

melted and solidified repeatedly.

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Type of glass Method of 

production

Composition Properties

Fused silica glass Silica, SiO2, is

heated until

melted at 1700 c

and cooled

rapidly

Silica or silicon

dioxide, SiO2

* very high

melting point

* not easy to

change its shape

* does not easily

expand or shrink

with changes of 

temperature

* transparent to

ultraviolet rays

Soda-lime glass Molten silica,

SiO2, is mixed

with sodiumcarbonate,

Na2CO3, and

calcium

carbonate, CaO3,

at 1500 c and

cooled.

Sodium silicate,

Na2SiO3, and

calcium silicate,CaSiO3

* transparents

* low melting

point*easily shaped

* easily broken

Borosilicate glass Molten silica,

SiO2, is mixed

with boron oxide,

B2O3

Silica, SiO2 and

boron oxide,

B2O3

* withstand heat

and chemical

reactions

* high melting

point* transparent to

light and infared

ray but not to

ultraviolet rays

* expands and

shrinks very little

and only whem

temperature

changes

Lead crystal

glass

Molten silica,

SiO2, is mixedwith lead(ii)

oxide, PbO, and

sodium oxide,

Na2O

Silica,Sio2,

lead(II) oxide,PbO, and sodium

oxide, Na2O

* very transparent

* shiny* high refractive

* high density

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6)  Different types of glass have different uses.

Types of glass Uses

Fused silica glass Lenses, spectacles, laboratory

glassware, ultraviolet column

Soda-lime glass Bottles, glass containers, mirrors,electrical bulbs, glass windows

Borosilicate glass Bowls, plates, saucers, pots,

cookware, laboratory glassware such

as test tubes, beakers and flasks

Lead crystal glass Lenses,prisms, glasses, ornamental

items (crystals)

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Composition, properties and uses of ceramics.

1)  ceramics are made from clay that has

been heated at a very high temperature.

2)  The main component of ceramics is

silicate.

3)  Most ceramics contain silicon, Si,

oxygen, o, and aluminium,Al.

4)  Unlike glass, ceramics cannot be

recycled. Ceramics that have been

solidified cannot be melted again as they

are extremely heat resistant.

5)  Common properties of ceramics are:

a)  brittle

b)  extremely hard

c)  high melting point

d)  withstand compression

e)  cracks when temperature changes

drastically

f)  inert to chemicals (withstand corrosion)

g)  good insulators of heat and electricity

6)  several uses of ceramics are as follows:

a)  manufacture of computer microchips

b) make dentures (enamel)

c)  make porcelain, vase and ornamental

items

d)  make plates, bowls and pots

e)  used in the manufacturing of car engines,

spacecraft, superconductors and nuclear 

reactors

f)  make construction materials such as

bricks, cement, tiles, underground piping

or roof tiles.

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1)  In this modern world, the demand for items with specific

properties is high.

2)  Compounds with specific properties are combined to produce a

composite material that meets the requirements of industry,

construction and transportation.

Composite materials

1)  Composite materials are produced from the combination of two

or more different compounds such as alloys, metals, glass,

polymers and ceramics

2)  The characterists of the produced material are much more

superior than those original components.

3)  Several uses of composite materials are:a)  Reeinforced concrete

y  Made from a mixture of cement, gravel, sand, water,

iron or steel to produce nets, rods or bars

y  Stron, high tensile strength and cheap

y  Construction material for buildings, bridges,

highways and dams

b)  Superconductor 

y  Made from various components such as the mixture

of niobium and germanium

y  Compound that has no electrical resistance (zero

resistance)

y  Can function only under extremely low temperature

y  Used in the transportation, telecommunications and

astronomy industries and in the medical field.

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c)  Fibre class

y  Made from silica, SiO2, sodium carbonate, Na2CO3

and calcium carbonate, CaCO3

y  Good insulator of heat and electricity

y  Used to make protective apparel for astronauts and

firefighters

d)  fibre optics

y  made from glass, copper and aluminium

y  enables information to be transmitted in light form at

high speeds (speed of light)

y  used in the field of communications to make

electrical cables and in the field of medicine to

observe internal organs without performing surgery.

e)  Photochromic glass

y  Produced from molten silica that is mixed with a

little silver chloride AgCl

y  Dark in colour when exposed to bright light

(ultraviolet ray) and bright when in the dark

y  Used to make optical lenses and glass windows

(windshields) of certain vehicles

f)  Ceramic class

y  Produced by exposing glass that contains certain

amount of metals to ultraviolet rays and heating it at

high temperaturesy  Withstand heat

y  Used to make cooking materials and rocket heads

g)  Plastic strengthened with glass fibres

y  Made of plastic and glass fibres

y  Composite plastics that are very strong, light, easily

formed and can withstand corrosion

y  Used to make helmets, the body of cars and

aeroplanes, rods and other parts of aeroplanes

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The uses of sulphuric acid in daily life

  Sulphuric acid,H2SO4 is a non-volatile diprotic acid and is also

one of the most important chemical used in chemical industries. 

  Sulphuric acid is used to make :

E.g: Calcium hydrogen phosphate is formed when sulphuric acid

reacts with calcium phosphate.2H2SO4+Ca3(PO4)2 Ca(H2PO4)2 +2CaSO4

 Ammonium sulphate is prepared from sulphuric acid andaqueous ammonia.H2S04+2NH3 (NH4)2SO4 

 Pottasium sulphate is prepared from sulphuric acid andpotassium hydroxide.H2SO4+2KOH K2SO4+2H2O

  Artificial synthetic fibres are polymers.

  Detergents are synthetic cleansing agents.

  Sulphuric acid reacts with hydrocarbon to produce sulphonicacid which then neutralized with sodium hydroxide to producedetergent.

Fertilisers

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   Neutralisation of sulphuric acid with barium hydroxide produces

barium sulphate which is the white pigment in paint

Environmental pollution by sulphur dioxide

Burning of fossil fuels

Fossil fuel such as petroleum.It contains sulphur.Sulphur dioxide is produced when fossil fuels are burned.

  Affects the respiratory system

Sulphur is a poisonous and acidic gas.It cause 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 producehigh sulphur dioxide content.

  Affect of acid rain

Sulphur dioxide gas dissolve in atmospheric water to producesulphurous acid, H2SO3 and sulphuric acid, H2SO4.These acidscauses acid rain.

Acid rain corrodes concrete buildings and metal structures.Acidrain increases the acidity of soil, unsuitable for growth anddestroys the roots of plants.Acid rain reacts with minerals in thesoil to produce salts which are leashed out of the top soil;essential nutrients for plants growth are depleted (plants die of malnutrition and diseases).Acid rain increases the acidity of water in lake and rivers, causes aquatic organisms die anddisturb the ecosystem.

SO2+H2O H2SO3

2SO2+O2+2H2O 2H2SO4 

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The industrial process in the manufacture of sulphuric acid

The contact process

Production of sulphur

dioxide gas

Conversion of sulphur

dioxide to sulphur

trioxide.

Production of sulphuric

acid

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*Burning of sulphur in dry

air in the furnace

*Burning of metal sulphidessuch as zinc sulphide andlead sulphide alsoproduces sulphur dioxide.

*The sulphur dioxide is mixedwith excess air.The mixtureis then dried and purified toremove impurities such as

arsenic compounds.

*Arsenic compounds found insulphur will poison the catalystin the converter, make the catalystineffective.

*Mixture of sulphur dioxide

and excess dry oxygen ispassed through a converter.

*Sulphur dioxide is oxidised tosulphur trioxide.

*98% conversion from sulphur 

dioxide to sulphur trioxide isachieved under conditions:

a)  Catalyst : vanadium( V )oxide,V2O5 

b)  Pressure : 1 atmosphere

c) Temperature : 450 c ² 550 c 

*In the absorber, sulphur 

trioxide is dissolved inconcentrated sulphuricacid to produce oleum,

H2S2O7, a viscousliquid.

*Oleum is then diluted with

equal volume of water to

produce concentratedH2SO4 ( 98% )2ZnS+3O2  SO2+2ZnO

2PbS+3O2 2SO2+2PbO

2SO2+O2 2S03 

SO3+H2SO4 H2S2O7 

H2S2O7+H2O 2H2SO4 

S+O2  SO2 

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The flow chart of contact process

o  The two reaction in stage 3 are equivalent to add sulphur trioxide to water.

SO3+H2O H2SO4

o  SO3 is not dissolved directly in water to produce H2SO4 because :

~ SO3 has low solubility in water ~ SO3 reacts violently in water , produce large amount of heat

which will vaporise sulphuric acid to form acid mist which is

corrosive, pollutes the air and is difficult to condense

o  The SO2 gas is dried and purified before added to dry air toproduce SO3 gas.This is

a)  to remove water vapour in the air b)  to remove contaminants such as arsenic

compounds

Sulphur 

Sulphur dioxide, SO2 

Sulphur trioxide, SO3 

Oleum,H2S2O7 

Sulphuric acid, H2SO4 

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Ammonia and its salt

The uses of ammonia in industry

Nitric acid ~ can be produced through oxidation o

ammonia when latinum is used as a catal st

Detergents ~ when ammonia reacts with oil from the

plants, detergents is produced

Prevent coagulation of latex ~ latex can be stored f

longer period of time before exporting

Paint and colouring ~ reaction of nitric acid and

organic compound can produce various type color

Synthetic fabric ~ ammonia is used to synthesis the

synthetic fabric

Explosive ~ reaction of nitric acid and toluena produce

explosive material

Cooling agent ~ ammonia is used as cooling agent in th

refrigerator.It has low point and therefore is very volat

Synthetic fertilizers ~ synthetic fertilisers can be produ

through neutralisation between ammonia gas and acid

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The manufacture of nitrogenous fertilisers

2NH3 + H2SO4  ( NH4 )2 SO4 

o  Ammonia reacts with sulphuric acid through neutralisation to produceammonium sulphate.

NH3 + HNO3 NH4NO3

o  Ammonia reacts with nitric acid through neutralisation to produceammonium nitrate.

Ammonium sulphate 

Ammonium nitrate

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2NH3+CO2  CO( NH2 )2 ( S ) +H2O

o  Ammonia reacts with carbon dioxide at temperature of 200 C and apressure of 200 atmosphere to produce urea.

Ostwald process : In the Ostwald process, ammonia is covered into nitric acid by three

stages.

Stage 1

Ammonia is oxidised to nitrogen monoxide gas in the presence of platinum as catalyst.

4NH3 + 5O 4NO + 6H2O

Stage 2

Nitrogen monoxide is further oxidized to nitrogen dioxide

2NO + O2  2NO2 

Stage 3

Nitrogen dioxide is dissolved in water produce nitric acid,

2NO2 + H2O HNO3 + HNO2 

Urea

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The properties of ammonia

  Very soluble in water

~ an inverted filtr funnel is used to prevent the sucking

back of water 

  Alkaline gas, colourless and pungent gas~ ammonia turns the damp red litmus paper blue~ the gas is less dense than air 

  To test ammonia gas~ ammonia gas reacts with hydrogen chloride gas to form white fumes of 

ammonium chloride

  Does not burn in air~ ammonia gas burns in oxygen to produce nitrogen monoxide gas

  Neutralisation~ ammonia is a week alkali which reacts with dilute acida in neutralisation to

produce salts

  R eacts with aqueuos metal ions~ aqueous solutions of ammonia react with metal ions( except Na+, k+ and Ca2+ )

to produce precipitate of metal hydroxides

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The industrial process in the manufacture of ammonia

* massive production of ammonia in an industrial sector is known as

Haber process

* nitrogen gas used in Haber process is obtained from the fractionaldistillation of liquid air.

y  Hydrogen gas can be obtained by two methods:

y  A) reaction between steam and heated coke (carbon)

y  Formula

y  H2o + CCo+H2

c)  Reaction between steam and naturalgas consist mainly of methane, CH4

Formula2HO + CH4 CO2 + 4H2

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 Steel

99.5%iron + 0.5%carbon

y very hard

y strong

 Manganese steel(hadfield steel)

85%iron + 13.8%manganese + 1.2%carbony very hard

 Duralumin

95%aluminium + 3%copper + 1%mangan + 1%manganesey hard

y does not corrode

y light but strong

 Pewter

97%tin + 3%antimony and copper y 

shiny and attractive appearancey  does not corrode

y  easily cast

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Ammonium fertilizers

o  Nitrogen is absorbed by plants in the form of soluble nitrates, NO3 produce protein

o  Ammonium fertilisers are chemical fertilisers that are used to replaceelements in soil used up by plants

o  Ammonium ions, NH4+ can be converted into nitrate ions by bacterialiving in the soil

o  The fertilizer with higher percentage of nitrogen is more effective andthis can be determined as below :

Percentage of nitrogen by weight

= Mass of nitrogen X100%

R elative molecular mass of fertilisers

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Alloys

~ An alloy is a mixture of two or more elements with a certain fixed

cmpositions in which the major component is a metal.

The physical properties of pure metal

~ pure metals are weak and soft because the arrangement of 

atom makes them ductile and malleable.

  DuctileDuctile is the ability of a metal to be stretched

  MalleableMalleable is the ability of a metal to be shaped

  High melting point and boiling pointsThe strong forces of attraction between metal atoms requires highenery to overcome it. Hence, metals have high melting point

  Good conductor 

  High densityIn solid state, the atoms in a pure metal are orderly aarranged andclosely packed, causes pure metal to have high density

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Arrangement of particles in pure metals

~ pure metals are soft and have atoms of same sizes

Meaning and purpose of making alloys

~ alloying is a process of mixing two or more metals ( or mixing metals

with elements such as carbon ) which cannot be separated by usingphysical way

Arrangement of particles in alloys

Atoms have different sizes

Disrupts the arrangement of atoms

Harder for layers of atoms tom slide over each other 

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Aim of making alloy

 To increase the strength and hardnessy  adding a little carbon to iron metal produces steel which is

very hard alloy of iron.

y  adding magnesium to aluminium metal produces an alloycalled Magnalium.

y  adding tin to copper metal produces Bronze is an alloyharder than tin and copper.

 To improve the appearance

y  pure metals can rust and tarnish easily because of theformation of metal oxides.

y  alloying can maintain the luster on the surface of metal.

  To prevent corrosion

y  pure metals such as iron and tin are easily corroded inpolluted, damp or acidic air 

y  alloying can prevent metals from corrosion due to theformation of oxide layer on the surface of the metal.

Carbon + nickel + chromium added

into iron metal produce

stainless steel

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