Coal and Petroleum

Coal and Petroleum 

Introduction

We use various materials for our basic needs. Some of them are found in nature and some have been made by human efforts.

Natural resources 

The sources which are obtained from nature are called natural resources.

Types of natural resources

1.      Inexhaustible natural resources

These sources are present in unlimited quantity in nature and are not likely to be exhausted by human activities. Examples: Sunlight, air, etc.

2.      Exhaustible natural resources

   The amount of these resources in nature is limited, they can be exhausted by human activities. Examples: Forests, coal, petroleum. minerals, wild life, natural gas, etc.

· Coal, Petroleum and Natural Gas are exhaustible natural resources. They are fossil fuels.

Fossil Fuels

·Fuels produced naturally from the dead remains of plants and animals that got buried in soil and rocks are called fossil fuels. 

·They are concentrated stores of energy and give off heat and light on burning.

What are fuels?

 Fuels

     A fuel is a substance, which bums In air to produce energy without releasing harmful gases in large quantities.

Fuels can be classified as natural (primary) fuels and derived (secondary) fuels. If a fuel is present in its natural state, it is called natural fuel. 

If a fuel is processed to improve its quality, it Is called derived fuel.

Calorific value of a fuel

       Calorific value of a fuel is the amount of heat liberated by complete burning of a unit mass or volume of a fuel. 

     For liquid or gaseous fuels, volume of fuel is considered while for solid fuels mass of fuel is considered to find out the calorific value.

Why do we need fossil fuels?

Fuels are required for different purposes such as:

1.    Transportation: fuels are used to run different vehicles such as cars, trucks, motorcycles, trains, airplanes etc.

2.    Cooking: fuels are needed for cooking. For instance, LPG is used in urban areas while firewood, coal and cattle dung is used in rural areas.

3.    Heating: fuel is also used to generate heat

4.    Electricity production: different fuels such as coal, petrol, natural gas and diesel are used to generate electricity in power plants

5.    Industrial usage: many industries use fuels for different purposes such as producing electricity, running their machinery and heating

6.    Rockets and other space vehicles: fuels called propellants are used in rockets that help in launching the space vehicles

What are the characteristics of a good fuel?

The characteristics of good fuel are:

·  It should be economical.

·  It should be available easily

· It should not emit poisonous gases on burning

·   It should produce large amounts of heat with respect to its mass (it should have a high calorific value)

·  It should be easy to transport and handle

· It should not produce a bad odour

· It should be clean and should not produce many ashes

· It should not ignite easily at room temperature

Coal-

· Coal is a fossil fuel formed from dead plant matter over millions of years due to heat and pressure. 

· Coal is a complex mixture of carbon, hydrogen and oxygen compounds. 

    nitrogen, sulphur and phosphorus compounds are also present in it. 

· It is found in coal mines deep under the surface of earth.

· Story of formation : It is believed that millions of years ago, the ground below the forests was split open by natural forces such as earthquakes and volcanoes. The forests got buried under the surface of earth.

   Thus, the plants had no contact with oxygen. Successive layers of sediments sealed the buried plants. 

Over millions of year, these deposits were subjected to tremendous pressure and heat finally transformed them into coal.

How is Coal formed?

      Figure 3 Formation of Coal

 ·   Over millions of years, coal is formed through different biological and geological processes on dead and decaying plant matter.

·    Coal mainly contains carbon. The process of conversion of dead vegetation into coal is called carbonisation.

·    Coal comes from a coal mine.

·    What is the composition of coal?

o    Coal consists of hydrogen, carbon and oxygen and sulphur (small amount).

 ·       What is coal mining?

o    Coal is extracted from the ground with a process called mining. Coal Mining can be of two types:

1.    Opencast Mining: Mining in which coal is extracted from near the earth’s surface

2.    Underground Mining: Mining in which coal is extracted from deep inside the earth’s crust.

Carbonisation: The chemical process involved in the transformation of plant matter into coal is called the carbonisation of plant matter.

The carbon content of coal depends upon the variety of the coal. The higher the temperature and pressure of the Earth and the longer the coal has been hurried under the Earth, the more is the carbon content in it.

So, the different varieties of coal are as follows-

(1) Peat 

(2) Lignite 

(3) Bituminous coal 

(4) Anthracite coal

 Peat: It is the youngest variety of coal which is light brown in colour. It contains minimum carbon content and produces less heat and more smoke on burning. Its calorific value is 10 to 15 kJ/g.

Lignite: It is known as soft coal. It is also brown in colour and contains more carbon than peat. Its calorific value is 15 to 20 kJ/g.

Bituminous coal: It is the common household coal. It is the most abundant f and Is compact, black, contains more carbon and produces more heat than peat and lignite. Its calorific value is 30 to 35 kJ/g.

Anthracite coal: It is the hardest coal containing maximum carbon. it burns with difficulty due to presence of very low volatile matter.

Therefore it is not used for household purposes, it is mainly used for industrial purposes. Its calorific value is 28 to 30 kJ/g

Different Types Coal

As coal gets older, the carbon content in it is higher. When coal is burnt, it mainly produces carbon dioxide gas.

Uses of Coal

·       Used as fuel to cook food.

·       Used in thermal power plants to produce electricity.

·       Used as fuel in various industries.

·       Once used as fuel to run steam-powered railway engines.

      When processed, coal yields coke, coal tar and coal gas which in turn is used by many industries.

What is destructive distillation?

         Figure 5 Destructive Distillation

It is a process in which coal is heated at very high temperature(1000ºC ) in the absence of air to obtain various useful products from it. Consider the diagram above to understand the process of destructive distillation. Different products obtained through this process are coal gas, coal tar, coke and liquor ammonia. These are-

(a) Coke : 

·  The residue left behind when destructive distillation of coal is carried out is coke. 

·  It is an almost pure form of carbon  It is a good fuel and burns with no smoke. 

·   It is also used to reduce metal oxides to get the metals.

(b) Coal gas

 ·  It is a mixture of hydrogen, methane, carbon monoxide and other gases.

 ·  It was earlier used for domestic cooking and lighting. 

(c) Coal tar

·   It is a thick viscous liquid. 

·   It contains several carbon compounds.

·  It is mainly used for road construction.

·   It is also used to make pesticides, explosives, synthetic fibres perfumes, naphthalene balls to repel moths and insects, dyes and paints. 

(d) Ammonium compounds

·   When dissolved in water, they give ammoniacal liquor. 

·   It is used for making nitrogenous fertilizers.

Figure 6 Destructive Distillation Process Flow Chart 

Major Coal Products

                   Figure 7.  Coal products

 What are hydrocarbons?

Hydrocarbons are the substances that consist of only carbon and hydrogen. Compounds like methane, butane, and hexane are hydrocarbons that are produced on burning of the fossil fuels.

What will happen if the coal reserves get depleted?

·   Coal is being used as a major source of energy in industries as well as rural areas.

·   Not only this, it serves various other purposes like the synthesis of synthetic oil, natural gas, coke, coal tar and coal gas.

·       If the amount of coal gets depleted it would become much difficult for us to produce energy for various purposes. Hence, we must use coal in an efficient way.

What substances are released on the burning of coal?

1.    Carbon dioxide

2.    Carbon monoxide

3.    Sulphur Dioxide

4.    Nitrogen

5.    Lead

6.    Arsenic

7.    Mercury

Petroleum

The term 'Petroleum' is derived from two words - 'Petra' which means 'rock' and 'oleum' which means 'oil'. It is mined from the rocks under the Earth.

Petroleum (also known as crude oil) is a fossil fuel formed from the remains of ancient marine organisms.

·      Petrol and diesel are obtained from a natural resource known as petroleum.

·      Petroleum was formed from the organisms living in the sea.

·      Over millions of years (the dead organisms buried inside the earth), in the presence high temperature, high pressure, and in the absence of air, the dead organisms transformed into petroleum and natural gas.

·      In 1859, the world’s first oil well was drilled in Pennsylvania, USA.

·      In 1867, oil was stuck at Makum in Assam, India.

·      In India, petroleum is largely found in Assam, Gujarat, Mumbai High, Maharashtra, and in the river basins of Godavari and Krishna.

How is Petroleum and Natural Gas formed?

·       When the sea organisms die, their bodies sink to the bottom of the sea. With time, they get covered by the layers of sand and clay.

·       Over millions of years, these remains get transformed in petroleum and natural gas due to high temperature, high pressure, and absence of air.

·       When we dig oil wells, natural gas is above crude oil which in turn is above water. This happens because gas and oil are lighter than water and do not mix with it.

First Oil Well in the World was drilled in Pennsylvania, USA in 1859. Second Oil Well in the World was drilled in Makum, Assam, India in 1867 (after eight years).

In India, the oil is found in:

·       Assam,

·       Gujarat,

·       Mumbai High, and

·       River basins of Godavari and Krishna.

 Petroleum

·      The following image illustrates the layer of gas and oil 

·      Petroleum is a mixture of various constituents such as petrol, petroleum gas, diesel, lubricating oil, paraffin wax, etc.

·      The process of separating the various constituents of petroleum is known  as refining.

·      The different useful substances, which are obtained from the petroleum and natural gas, are known as ‘Petrochemicals.’

·      Petrochemicals are used in the manufacturing of detergents, fibers (polyester, nylon, acrylic etc.), polythene and other man-made plastics.

·      Hydrogen gas, which is obtained from natural gas, is used in the production of fertilizers (urea).

·      Because of having the great commercial importance, petroleum is also known as ‘black gold.’

·  Natural gas  is  normally  stored  under  high  pressure  and  hence  known  as Compressed Natural Gas (CNG).

·    CNG is used for power generation and fuel for vehicles.

·      The following table illustrates various constituents of petroleum and their uses −

Refining of Petroleum

· Originally, petroleum is a mixture of many things, such as petrol, diesel, petroleum gas, paraffin wax, lubricating oil etc.

·  It is a dark and oily liquid with an unpleasant odour.

      ·  Refining of petroleum is the process by which different constituents of petroleum are separated.

·  This process takes place in a petroleum refinery.

Constituents of Petroleum and their Uses

Constituents of petroleum	Uses
Petroleum Gas in Liquid form (LPG)	Fuel for home and industry
Petrol	Motor fuel, aviation fuel, solvent for dry cleaning
Diesel	Fuel for heavy motor vehicles, electric generators
Kerosene	Fuel for stoves, lamps and for jet aircrafts
Lubricating oil	Lubrication
Paraffin wax	Ointments, candles, Vaseline, etc.
Bitumen	Paints, road surfacing

          Figure 11 Constituents of Petroleum

Why Petroleum is called ‘black gold?

Petroleum is called 'black gold' because it yields several substances that are commercially successful. The useful substances obtained from petroleum and natural gas are called 'petrochemicals'.

Petrochemicals are used in manufacturing:

·       Synthetic fibres (such as Polyester, Nylon, Acrylic etc.),

·       Detergents,

·       Polythene, and

·       Man-made plastics.

Natural gas also yields Hydrogen gas which is used in the production of fertilisers (such as urea).

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Quiz-1 Carbon and its compounds

Carbon and its compounds-1

Quiz

 

1. Which of the following statements are correct for carbon compounds?
   (i) Most carbon compounds are good conductors of electricity.
   (ii) Most carbon compounds are poor conductors of electricity.
   (iii) Force of attraction between molecules of carbon compounds is not very strong.
   (iv) Force of attraction between molecules of carbon compounds is very strong.
   1.   (ii) and (iv)
   2.   (ii) and (iii)
   3.   (i) and (iv)
   4.   (i) and (iii)
2. C3H8 belongs to the homologous series of
   1.   Alkynes
   2.   Alkenes
   3.   Alkanes
   4.   Cyclo alkanes
3. The number of isomers of pentane is
   1.   2
   2.   3
   3.   4
   4.   5
4. Which of the following will undergo addition reactions?
   1.   CH4
   2.   C3H8
   3.   C2H6
   4.   C2H4
5. When ethanoic acid is treated with NaHCO3 the gas evolved is
   1.   H2
   2.   CO2
   3.   CH4
   4.   CO
6. Name the functional group present in CH3COOH.
   1.   Alcohol
   2.   Carboxylic acid
   3.   Ketone
   4.   Aldehyde
7. Name the functional group present in CH3COCH3.
   1.   Alcohol
   2.   Carboxylic acid
   3.   Ketone
   4.   Aldehyde
8. Why does carbon form compounds mainly by covalent bonding?
   1.   There are four electrons in the outermost shell of carbon.
   2.   It requires large amount of energy to form C4+ or C4-.
   3.   It shares its valence electrons to complete its octet.
   4.   All the above
9. Addition reactions are undergone by
   1.   saturated hydrocarbons (alkanes)
   2.   only alkenes
   3.   only alkynes
   4.   both alkenes and alkynes
10. The first member of the alkyne homologous series is
    1.   propyne
    2.   ethyne
    3.   methane
    4.   ethene
11. In diamond, each carbon atom is bonded to four other carbon atoms to form
    1.   a hexagonal array
    2.   a rigid three-dimensional structure
    3.   a structure in the shape of a football
    4.   a structure of a ring
12. Cation is formed when:
    1.   Atom gains electrons
    2.   Atom loses electrons
    3.   Proton is lost by the atom
    4.   Atom shares electrons
13. The property of self-linkage among identical atoms to form long chain compounds is known as:
    1.   Catenation
    2.   Isomerisation
    3.   Superposition
    4.   Halogenation
14. Which of the following statements about graphite and diamond is true?
    1.   They have the same crystal structure
    2.   They have the same degree of hardness
    3.   They have the same electrical conductivity
    4.   They can undergo the same chemical reactions
15. How many number of carbon atoms are joined in a spherical molecule of buckminsterfullerene?
    1.   30
    2.   60
    3.   90
    4.   120
16. 1.   30
    2.   60
    3.   90
    4.   120
17. Which of the followings is the major constituent of the liquefied petroleum gas?
    1.   Methane
    2.   Ethane
    3.   Propane
    4.   Butane
18. From which of the following substance pencil lead is formed?
    1.   Charcoal
    2.   Wood
    3.   Lead
    4.   Graphite
19. Ester is formed by the reaction between:
    1.   An acid and an alcohol
    2.   An acid and a base
    3.   A base and an alcohol
    4.   An acid and an alkene
20. What is denatured alcohol?
    1.   Ethyl alcohol which has been made unfit for drinking purpose by adding small amount of poisonous substance
    2.   Methyl alcohol which has been made unfit for drinking purpose by adding small amount of poisonous substance
    3.   Alcohol having properties of an acid
    4.   Ethyl alcohol containing 60% of water by weight
21. Which of the following substance produces brisk effervescence with baking soda solution?
    1.   Ethanoic acid
    2.   Table salt
    3.   formaldehyde
    4.   Sunflower oil
22. Which of the following statements is true about carbon?
    1.   Carbon is the main component of carbohydrates.
    2.   Carbon is a major component of living beings.
    3.   Carbon is one of the basic building blocks for organic life
    4.   All of the above