Chapter 8CHEMICALS IN INDUSTRY.

8.1 Properties of Alloys and Their Uses in Industry.

Alloys. is formed when a pure metal is added with a small amount of impurity. an alloy is a mixture of two or more metals (ex: bronze or brass) or a metal

with a small amount of non-metal (like steel). the process of mixing of foreign atoms into pure metals is called alloying. examples of goods made of alloy are kitchen utensils, coins, keys, etc. alloying can change the properties of metals, for example :

a) increasing the hardness of metals.o aluminium and magnesium are soft and light.o hence, these metals are not suitable for us as

construction materials.o through the alloying process, aluminium is added with

magnesium in suitable composition to produce and alloy that is hard and light.

b) preventing corrosiono pure iron rusts and corrodes easily.o stainless steel which is rust resistant can be obtained by

adding a small amount of chromium and nickel to iron.c) improving the appearance of metals

o the surface of copper becomes dull easily.o if copper is added with a small amount of zinc, brass,

which is and alloy with a shiny surface is produced.

Example of alloy

Composition Properties Uses

Steel Iron 99.5%Carbon 0.5%

Hard, strong Building houses, bridges, machines, vehicles, etc.

Pewter Tin 97%Antimony and copper 3%

Shiny surface, corrosion resistant

Making of decorative goods like photo frame.

Bronze Copper 88%Tin 12%

Hard, does not rust Making of coins, knives, etc.

Brass Copper 75%Zinc 25%

Strong, shiny surface, malleable

Making of keys, musical instruments, etc.

Duralumin Aluminium 95%Copper 3%Magnesium 1%Manganese 1%

Light, strong, corrosion resistant

Making of vehicle bodies like buses, aeroplanes, trains, etc.

Relationship between the properties of alloys and the arrangement of their particles.

a pure metal is soft and not strong because the size of its atoms is the same and they are arranged closely to from layers at metal atoms.

consequently, the layers of atoms slide over one another easily when force is applied.

arrangement of particles in pure metals

when atoms of other metals with different sizes are added to atoms of pure metals, this will disrupt the arrangement of the layers of atoms and make it difficult for them to slide over one another.

usually, a small amount of another metal is added to a pure metal to make it harder and stronger.

atom of pure metal atom of foreign metal

arrangement of particles in an alloy

Importance of alloy in industry.

Superconductor alloy is an electric conductor which allow electric current to flow through it a t

zero resistance when cooled at a very low temperature. saves electricity if compared to a conductor made of copper. has magnetic properties – this causes vast development in its usage

today.

applied force

pure metal atom layers of

atoms which slide over

easily

Field UseTransportation Use of magnet in magnetic-levitation (MAGLEV) train

increases its speed.Telecommunication and astronomy

A superconductor alloy can detect rays at wavelengths that cannot be detected existing instruments.

Industry A superconductor alloy is used to generate power and increase the stability of energy stored after it has been generated. Electric wires made of superconductor alloy can transmit electric current over long distances without losing energy.

Medicine A superconductor electromagnet is put into a patient’s body to enable doctors to examine some of the patient’s organs visually using a computer.

Electronics The switch that controls the electric circuit in the computer can operate at a fast rate without producing heat.

Weaponry defence Superconductor alloys are used to detect mines placed in the sea.

uses of superconductor alloy in industry.

8.2 Uses and Production of Ammonia in Industry.

Ammonium molecule and its characteristics. ammonia molecule consists of one nitrogen atom and three hydrogen

atoms. ammonia is a gas that is alkaline, colourless, pungent and dissolves easily

in water.

ammonia molecule

Uses of ammonia and its compounds in daily life. Making of ammonia fertilisers.

o Ammonia solution is alkaline. When it reacts with acid, ammonia fertiliser is produced. For example,

(a) ammonia solution + sulphuric acid ammonium sulphate. (b) ammonia solution + nitric acid ammonium nitrate

N

HH

H

(c) ammonium solution + phosphoric acid ammonium phosphate

Making of nitric acid.o Ammonia is used to manufacture nitric acid.o The nitric acid obtained is used to make fertilisers,

explosives, etc. Making of colourings.

o Ammonia is used to make colourings.o Colourings are used in textile and paper industries.

Making of cleaning agents.o When ammonia solution reacts with plant oil, a cleaning

agent is produced.o For example, detergent.

Making explosives.o Nitric acid is produced from ammonia.o When nitric acid reacts with toluene, an explosive substance

is produced. As cooling agents.

o Ammonia is used to make cooling material used in refrigerator and air-conditioning units.

Preventing coagulation of latex.o ammonia neutralises the acid produced by bacteria found in

latex to prevent the latex from coagulating.

Production of ammonia in industry. ammonia is produced on a large scale in the factory through the Haber

process using nitrogen and hydrogen. the equation is as follows:

Nitrogen + Hydrogen Ammonia (volume ration of nitrogen to hydrogen is 1 : 3)

conditions : temperature: 450oC-500oC pressure: 200-500 atmosphere catalyst: iron fillings

flow chart showing the production of ammonia.

Factors which affect the optimum production of ammonia are:1. temperature2. pressure3. catalyst

the reaction between nitrogen and hydrogen:(a) the reaction between nitrogen and hydrogen is an exothermic

reaction.(b) the decrease of temperature encourages the production of

ammonia.(c) however, temperature that is too low will cause the rate of

reaction to fall.(d) therefore, the optimum temperature is between 450oC - 500oC.

the production of ammonia increases at a higher pressure. however, if the pressure is too high a technical problem will occur such as

the stability of the equipments used. So, 200-500 atmospheric pressure is used.

so, 200 – 500 atmospheric pressure is used. iron filings are used as a catalyst to increase the rate of reaction. even then, the catalyst does not affect the percentage of ammonia

produced.

Production of ammonium salt fertilisers in industry. ammonia fertiliser is a nitrogen fertiliser that supplies nitrogen element to

animals and plants during the formation of protein. examples of ammonia fertiliser are ammonium sulphate, ammonium

nitrate, and ammonium phosphate. the following steps show how ammonia fertiliser is prepared:

Nitrogen and hydrogen are used in the ratio of 1 : 3 according to volume. The two gases are purified and dried.

The gas mixture is compressed under a pressure of 200-500 atmosphere and channelled through iron fillings which functions as catalyst at a temperature of 400-500oC.

The nitrogen reacts with hydrogen to produce ammonia gas.

The ammonia gas produced is cooled to form ammonia liquid or dissolved in water to form ammonia solution.

(a) ammonia solution + acid ammonium salt(b) ammonium salt is evaporated to obtain saturated ammonium

salt solution(c) the saturated ammonium salt solution is cooled and crystallised

to obtain ammonia fertiliser.

Neutralisation reactionAlkali Acid

Ammonium salt/ fertiliser

Ammonia solution + Sulphuric acid Ammonium sulphate

Ammonia solution + Nitric acid Ammonium nitrate

Ammonia solution + Phosphoric acid Ammonium phosphate

production of ammonia fertiliser

Manufacture of urea in industry. urea is a fertiliser that contains a higher percentage pf nitrogen

compared to ammonia fertiliser. urea can be prepared heating a mixture of liquid ammonia and

liquid carbon dioxide at a temperature of 200oC and of 200 atmospheric pressure.

Ammonia + Carbon Urea + Water both materials react at high temperature and pressure to form

ammonium carbamide salt. the salt is then decomposed at a lower pressure to produce

urea and water.

8.3 Effects of Industrial Waste Disposal on The Environment.

1. Environmental pollution is caused by irresponsible human activities.2. Industrial waste disposal brings adverse effects to the environment and

consequently affect the survival of living things and the ecosystems.3. Generally, environmental pollution damages the quality of air and water.4. Methods of controlling industrial waste disposal need to be implanted to

prevent environmental pollution.

Source of Pollution

Main Pollutants Effects of Pollution Methods of Controlling Pollution

Burning of fossil fuels such as petroleum, natural gas and coal

Soot and dust - blurs the view- damages the respiratory system- closes the stomata of plants and disrupts photosynthesis

- install and electrostatic depositor on factory chimneys to remove pollutants from smoke before releasing the smoke into the air.

Carbon dioxide - causes greenhouse effect which increases global temperature

- planting many green plants to remove carbon dioxide from the air.

Carbon monoxide - reduces the ability of blood to carry oxygen in the body

- install equipment such as catalyst converters which convert carbon monoxide into carbon dioxide.

Sulphur dioxide and nitrogen dioxide

Dissolve rainwater to form acid rain which- lowers the pH value of water and soil- damages the respiratory system- causes lung diseases

- dissolve acidic gases using an air cleaner system to prevent the gases from being released into the air.

Toxic substance from chemical industry

Acid and alkali - changes the pH value of water and soil

- tighten the law to prohibit the dumping of chemical wastes in territorial waters.- toxic wastes to be stored in oxidation ponds for biological and chemical processes

Nitrate and phosphate compounds

- increases the contents of mineral in river water, lake water or pond water which disrupts the balance of aquatic ecosystems

Toxic metals (such as lead, mercury, nickel, arsenic and cadmium)

- lead and mercury poison the brain and nervous system- nickel causes lung cancer- arsenic and cadmium poison the lungs and kidneys

Industries that use radioactive materials

Radioactive wastes

Cause- cancer- infertility- foetal deformity- death under unpleasant conditions

- the authorities to impose strict control to ensure that radioactive wastes are disposed of safely and far away from residential areas- keep radioactive wastes in thick lead or concrete containers and follow the required disposal procedure.

Agricultural industry

Oil palm wastes (such as stalk, oil and skin of fruit)

- burning of wastes pollutes the air.- oil thrown into water covers the surface of water and block the oxygen from dissolving in it- organic wastes are decayed by bacteria and this reduces the contents of oxygen in the water

- tighten law to prohibit indiscriminate disposal of chemical wastes to the environment- oil palm wastes are processed to become food for livestock or fuel- rubber wastes are reused to make shoes or slippers

Rubber wastes (organic and chemical substances)

- causes water pollution- rotting wastes produced unpleasant smelling gas- chemical wastes make water unsuitable for aquatic life.

8.4 The Need For Preservation and Conservation of The Environment From Industrial Waste Pollution.

pollutants from industrial wastes enter our body through:o the air we breatheo the water we drinko the food we eat, whether it is vegetable or meat

uncontrolled disposal of industrial wastes causes environmental pollution.

Importance of Practising a Responsible Way of Disposing Industrial Wastes

1. Good quality environment refers to a safe, clean, harmonious and balanced nature.

2. Therefore, disposal of industrial wastes should be managed in a controlled and responsible manner. It is important to preserve and conserve the environment from being polluted by industrial wastes so that:

a. human health is not threatenedb. flora and fauna are protectedc. the continuity of future generations can be ensured

3. Importance of preserving and conserving the environment:a. maintaining the beauty of natureb. preserving biodiversityc. a clean environment enables recreational activities to be conductedd. preventing the extinction of any species of plant of plant or animal

on Earth

Adverse effects of pollution resulting from industrial

waste disposal

Human Health- the polluted environment dangers human health.- for example, soot and dust damage the respiratory system, while radioactive rays cause cancer.

Destruction of habitats of living things and the

extinction of flora and fauna species

- the destruction of habitats of living things owing to pollution causes the extinction of animal and plant species.- extinction of these species causes the future generation to get to know certain plants or animals only through photographs.- destruction of plants in large scale reduces the contents of oxygen in the air.Loss of economic source- acid rain makes the soil unsuitable for cultivation.- water pollution causes the death of aquatic plants. this will reduce the income of certain people.