Folio Chemistry Chapter 9
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Transcript of Folio Chemistry Chapter 9
Name : Fatin Nadzirah Binti Yusof
No Maktab : 11435
Kelas : 4B (2011)
Guru MP : Miss Zurina
9.1 Sulphuric Acid
Uses of sulphuric acid
1. Sulphuric acid is used to manufacture almost all products. Some of the example are : Fertilisers Paint pigment Detergents Synthetic fibres Electrolyte in car batteries Cleaning metals Plastics Other chemicals
2. Sulphuric acid is also used in laboratory in school as follows: As drying agent As dehydrating agent As catalyst As strong acid
Manufacture of sulphuric acid in industry
CONTACT PROCESS
Stage 1: Combustion of Sulphur In the furnace, molten sulphur is burnt in dry air to produce sulphur dioxide, SO2. The
gas produced is purified and cooled.S(l) + O2(g) SO2(g)
Stage 2: Conversion of sulphur dioxide to sulphur trioxide in the converter In the converter, sulphur dioxide, SO2 and excess oxygen gas, O2 are passed over a
few plates of vanadium (V) oxide, V2O5 catalyst at 4500C to produce sulphur trioxide, SO3.2SO2(g) + O2(g) 2SO3(g)
About 99.5% of the sulphur dioxide, SO2 is converted into sulphur trioxide, SO3 through this reversible reaction.
Stage 3: Production of sulphuric acid in absorber and diluter In the absorber, the sulphur trioxide, SO3 is first reacted with concentrated sulphuric
acid, H2SO4 to form a product called oleum, H2S2O7.SO3(g) + H2SO4(l) H2S2O7
The oleum, H2S2O7 is then diluted with water to produced concentrated sulphuric acid, H2SO4 in large quantities.H2S2O7(l) + H2O(l) 2H2SO4(l)
The two reactions in the third stage are equivalent to adding sulphur trioxide, SO3 directly to water.SO3(g) + H2O(l) H2SO4(l)
Environmental pollution by sulphuric acid
1. Sulphur dioxide is an acidic and poisoinous gas that pollutes the environment.
2. The sources of sulphur dioxide :
3. Sulphuric acid is formed by atmospheric oxidation of sulphur dioxide in the
presence of water. It also produces sulphurous acid.
4. Sulphuric acid and sulphurous acid are constituents of acid rain.
5. 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.
6. 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
iii. Neutralise the acidic soil and water by treating them with calcium oxide,
calcium hydroxide and calcium carbonate.
9.2 Ammonia and Its Salts
Uses of ammonia
1. Ammonia is produced industrially as an intermediate compound and as raw material
for many other chemical processes.
2. The main uses of ammonia are as follows :
To manufactured nitrogenous fertilisers needed for plant growth
As raw material for the manufactured of nitric acid
As cooling agent in refrigerators
To produce ammonium chloride used as electrolyte in dry cells
To prevent coagulation of latex
To make synthetic fibres such as nylon
As smelling salts to revive people who have fainted
Making of explosives
Properties of ammonia
1. Ammonia is a covalent compound with the following physical properties :
Manufacture of ammonia in industry
HABER PROCESS
1. Gases mixed and scrubbed Haber process combines N2 gas from the air with H2 gas from natural gas to form
NH3. The two gases are mixed. The mixture is scrubbed to get rid of impurities.2. Compressor
One volume of N2 gas and three volume of H2 gas is compressed to a pressure of 200 – 500 atm
N2(g) + 3H2(g) 2NH3(g)3. Converter
Then, it goes to the converter. It is then passed through layers of iron catalyst with aluminium oxide as a promoter at a temperature of 4500C – 5000C
4. Cooler A mixture of three gases leaves the converter. It is cooled until the ammonia
condenses. The nitrogen and hydrogen are pumped back to the converter for another chance to react.
5. Storage tanks NH3 is formed and then liquefy and separated to get a better yield. The NH3 is run
into tanks and stored as a liquid under pressure.
Ammonium Fertilisers
1. Nitrogen is used by plant to make protein. Protein is important for the growth of
plants. Other nutrients needed by plants include phosphorus, potassium, calcium and
magnesium.
2. Nitrogenous compounds are removed from the soil by the plants. Some are replaced
naturally by bacteria. To restore the balance, nitrogenous fertilisers are added to the
soil.
3. Nitrogenous fertilisers contain ammonium ions.
4. In the soil, the ammonium ions are converted to nitrate ions by the bacteria. This is
because nitrogen can only be absorbed by plants in the form of soluble nitrate ions.
5. Examples of ammonium fertilisers are :
Ammonium nitrate
Ammonium sulphate
Ammonium phosphate
Urea
6. The effectiveness of ammonium fertilisers is determined by the percentage of nitrogen
by mass in them.
7. The fertilisers with a higher percentage of nitrogen is more effective for growth than
those fertilisers with a low percentage of nitrogen.
8. The percentage of nitrogen by mass can be calculated from the formulae of the
fertilisers using the following formula.
9.3 Alloys
Pure Metal
Typical pure metals have the following physical properties :
Ductile
Malleable
Lustrous
High density
High melting and boiling points
Good conductors of heat and electricity
2. Pure metals are weak and soft because the arrangement of atoms in pure metals make
them ductile and malleable.
3. A pure metal contains atoms of the same size arranged in a regular and organized
closed-packed structure.
4. 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 metals ductile and can be
drawn to form long wires.
5. 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.
6. The strong forces of attraction between metal atoms requires high energy to overcome
it. Hence, most metals have high melting points.
7. The close-packed arrangement of metal atoms results in the high density of metals.
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
atom 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.
6. 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
The Composition, Properties and Uses of Some Alloys
Alloy Composition Properties Uses
Bronze80% copper
20% tin
Hard, strong, does not
corrode easily, shiny
surface
Medals, statues, monuments,
arts,materials
Brass70% copper
30% zincHarder than copper
Musical instrument,
kitchenware, door knobs,
bullets cases, decorative
ornaments, electric parts
Cupro-nickel75% copper
25% nickel
Beautiful surface,
shiny, hard, does not
corrode easily
Coin
Steel99% iron
1% carbonHard, strong
Buildings, bridges, body of
cars, railway track
Stainless steel
74% iron
8% carbon
18% chromium
Shiny, strong, does
not rust
Cutlery, sinks, pipes, surgical
instruments
Duralumin
93% aluminium
3% copper
3% magnesium
1% manganese
Light, strongBody of air crafts, bullet trains,
racing bicycles
Pewter
96% tin
3% copper
1% antimony
Shiny, strong, does
not corrodeArt objects, souvenirs
Solder50% tin
50% lead
Hard, shiny, low
melting point
Soldier for electric wires and
metal
9-carat gold
37.5% gold
51.5% copper
11% silver
Shiny, strong, does
not corrodeJewellery
9.4 Synthetic Polymers
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
Involves monomers with the carbon-carbon double bonds between the carbon
atoms smaller and simple molecules such as water.
b) Condensation polymerization
Involves the joining up of monomers with the formation of other
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:
Naturally occurring polymers
This type of polymer exists in living things in nature like the plants and
animals.
Examples of naturally occurring polymers are:
Protein
Carbohydrate
Natural rubber
Naturally occurring polymers are formed by the joining of monomers by
polymerization.
Synthetic polymers
These types of polymer are man-made by chemical process in the laboratories.
The raw materials for synthetic polymers are obtained from petroleum.
The types of synthetic polymers include:
Plastics
Fibres
Nylon
Plastic
1. Plastics are made from the products of cracking of petroleum fractions such as
alkenes molecules through addition polymerisation.
2. Plastics are the largest group of synthetic polymers with the following properties :
Can be easily moulded and coloured
Low density
Strong
Inert to chemicals
Insulators of heat and electricity
Impermeable
Non-biodegradable
Monomers, Properties and Uses of Some Commonly Plastic
Name of polymer Monomers Properties Uses
Polythene Ethane
Durable, light,
impermeable, inert to
chemistry, easily melt,
insulator
Shopping bags, plastic
cups and plate, toys
Polypropene Propene
Durable, light,
impermeable, inert to
chemistry, easily melted,
insulator, can be moulded
and coloured
Bottles, furniture, battery
casing, pipes, toys
Polystyrene PhenyletheneHeat insulator, light, can
be moulded, impermeable
Disposable cups and
plates, packaging
materials, toys, heat
insulator
PerspexMethyl
methacrylateTransparent, strong, light
Replacement for glass.
Lenses, optical fibres
Teflon Tetrafluoroethene
Durable, non-stick,
chemically inert, strong,
impermeable
Coating for non-stick
pans, electrical insulators
Advantages of synthetic polymers
Strong and light
Cheap
Able to resist corrosion
Inert to chemical reactions
Easily moulded or shaped and be coloured
Can be made to have special properties
Environmental pollution caused by synthetic polymers
As most of polymers are non-biodegradable, they will not decay like other organic
garbage.
Burning of polymers release harmful and poisonous gases.
Methods to overcome the environmental pollution caused by synthetic
polymers
Reduce, reuse and recycle synthetic polymers
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 :
Hard and brittle
Inert to chemical reactions
Insulators or poor conductors of heat and electricity
Withstand compression but not stretching
Can be easily cleaned
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.
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
Composition, Properties and Uses of Different Types of Glass
Name of glass Properties Composition Uses
Fused glass
High melting
point
High
temperature
High chemical
durability
Resistant to
thermal shock
Transparent to
ultraviolet and
infrared light
Silicon dioxide
Laboratory
glassware
Arc tubes in lamps
Lenses
Telescope mirrors
Optical fibres
Soda-lime glass Low melting
point
High thermal
expansion
coefficient
Does not
withstand heat
Cracks easily
with sudden
change in
temperature
Silicon dioxide
Sodium oxide
Calcium oxide
Containers such as
bottles, jars and
tumblers
Flat glass
Windowpanes
Mirrors
Light bulbs
Industrial and art
objects
Good chemical
durability
Easy to mould
and shape
Transparent to
visible light
Borosilicate glass
Transparent to
visible light
Resistant to
chemicals
Lower thermal
expansion
coefficient
Resistant to
thermal shock
Can withstand
wide range of
temperature
changes
Silicon dioxide
Boron oxide
Sodium oxide
Calcium oxide
Cookware
Laboratory
glassware
Automobile
headlights
Glass pipelines
Electrical tubes
Lead crystal glass
Soft and easy to
melt
Transparent to
visible light
High density
High refractive
index
Silicon dioxide
Lead(11) oxide
Sodium oxide
Tableware
Art objects
Crystal
Prism
Lenses
Ceramics
1. Ceramics are made from clay and composed of aluminium silicate mixed with sand.
2. The white clay used to ceramics is kaolin which is in rich in kaolinite or hydrated
aluminosilicate.
3. Red clay consists of iron(III) oxide which gives the red colour.
4. Brick, tiles, mugs and clay pots are some examples of traditional ceramics
5. During the making of ceramics, the shaped objects are heated to very high
temperature. They undergo a series of chemical reactions and are hardened to form
ceramics.
6. These chemical reactions are irreversible and the ceramics cannot be melted and
moulded.
How Ceramic are Made
1. Wet clay can be shaped easily because the tiny crystals in it can slide over each other.
Clay has a plastic property. When the clay dries up, it keeps its shape as the crystals
are now stuck together.
2. When heated to above 15000C, a series of chemical reaction produce other chemicals
and glass which packs the tiny mineral crystals together.
3. The object is now glazed and heated again. The reactions in the glaze cause the
surface to be waterproof.
Properties of Ceramics
Very strong and hard
Brittle
Chemically inert and does not corrode
Good insulator of electricity and heat
Very high melting point and heat resistance
Porous but can be made impervious by glazing
Uses of Ceramics
Property Uses Examples
Hard and strong Building materialsTiles, bricks, roofs, cement,
abrasive for grinding
Attractive, easily moulded
and glazed
Decorative pieces and
household items
Vases, porcelain ware, sinks,
bathtubs
Chemically inert and non-
corrosiveKitchenware Cooking pots, plates, bowls
Very high melting point and
good insulator of heatInsulation
Lining of furnace, engine
parts
Electrical insulatorsInsulating parts in electrical
appliances
Spark plugs, insulators in
ovens and electric cables
Inert and non-compressible Medical and dental apparatus Artificial teeth and bones
9.6 Composite Materials
1. Composite material is a structure material that is formed by combining two or more
different substances like metals, alloys, glass, ceramics and polymers. Usually, the
new composite materials formed have properties that are superior to those of the
original components.
2. The composite materials produced are harder, stronger, lighter, more resistant to heat
and corrosion and also for specific purposes.
3. When composite material is formed, the weakness of the components will not exist
anymore.
Comparison of the Properties between Composite Materials with Those of Their Original
Components
Composite
materials
Original
components
Properties
Original Composite
Reinforced
concrete
Concrete
Hard, low tensile strength,
does not rush, high
compression strength,
brittle, fireproof,
waterproof, easy to
maintain and cheap
High tensile strength,
tough, does not crack
easily, relatively cheap,
can be moulded easily,
very low building cost
and needs very little
maintenance SteelGood tensile strength, rust,
expensive
Superconductor
Yitrium oxide,
barium carbonate,
copper(III) oxide
Non-conductor with high
resistance to electricity
Very good conductor
with very little
resistance
Fibre optic
GlassHigher refractive index,
non-conductor
Transparent, cheaper in
materials cost, much
thinner, easily bend and
lighter, less susceptible
to interference, much
greater bandwidth, carry
more data, chemically
more stable than metal
wires and data is
transmitted digitally
PlasticLower refractive index,
non-conductor
FibreglassPlastic Soft, flexible, low density
Hard, strong, densityGlass Brittle, strong, hard
Photochromic
glass
GlassTransparent, not sensitive to
lightTransparent and
sensitive to intensity of
lightSilver chloride,
Silver bromide
Sensitive to intensity of
light