Lakhmir Singh & Manjit Kaur: Coal And Petroleum- 2 | Lakhmir Singh & Manjit Kaur Solutions: Class 8 Science PDF Download

Q.31. State the various uses of natural gas.

Natural gas is a very important fossil fuel because it is easy to transport through pipes. It can be used as a fuel in homes and factories. It is also used as a starting material for the manufacture of a number of chemicals and fertilizers.

Q.32. What is CNG? State its one use.

CNG is compressed natural gas. Natural gas is a very important fossil fuel because it is easy to transport through pipes. Natural gas is stored under high pressure as compressed natural gas (CNG). It can be used as a fuel in homes and factories. It is also used as a starting material for the manufacture of a number of chemicals and fertilizers.

Q.33. Where the natural gas found? Why is natural gas called a clean fuel?

India has huge reserves of natural gas. It has been found in Tripura, Rajasthan, Maharashtra and in the Krishna Godavari delta. It is advantageous to use CNG as a fuel because it is less polluting than petrol. It is a clean burning fuel. It produces 45% less hydrocarbons than petrol. The great advantage of CNG is that it can be used as fuel in homes and factories where it can be supplied through pipes.

Q.34. What are the advantages of using LPG as fuel?

LPG stands for liquified Petroleum Gas. It is used as fuel for home and industry. Advantages of using LPG as a fuel is that it is non-toxic and reduces the interior pollution by 90% as compared to other fuels such as coal or wood. The carbon dioxide emissions are very low. It is an economical fuel source. It burns very efficiently, with very low combustion emissions and does not create black smoke.

Q.35. Name any five useful substances which are manufactured from petrochemicals.

Many useful substances are obtained from petroleum and natural gas. These are termed as ‘Petrochemicals’. These are used in the manufacture of detergents, fibres (polyester, nylon, acrylic etc.), polythene and other man-made plastics. Hydrogen gas obtained from natural gas, is used in the production of fertilisers (urea).

Q.36. Which material is called ‘black gold’? why?

Many useful substances are obtained from petroleum and natural gas. These are termed as ‘Petrochemicals’. These are used in the manufacture of detergents, fibres such as polyester, nylon, acrylic etc., polythene and other man-made plastics. Hydrogen gas obtained from natural gas, is used in the production of fertilisers such as urea. Due to its great commercial importance, petroleum is also called ‘black gold’.

Q.37. (a) Where and when was the world’s first oil well drilled?
(b) Where and when was oil first struck in India?

(a) The world’s first oil well was drilled in Pennsylvania, USA, in 1859

(b) At Makum in Assam, in 1867, oil was stuck in India. Oil is found in Assam, Gujarat, Mumbai High and in the river basins of Godavari and Krishna.

Q.38. State one use each of the following products of petroleum:
(a) petroleum gas,
(b) petrol,
(c) Diesel,
(d) Lubricating oil,
(e) Bitumen

(a) Petroleum gas is used as fuel for home and industry.

(b) Petrol is used as a Motor fuel, aviation fuel and solvent for dry cleaning.

(c) Diesel is used as a fuel for heavy motor vehicles and electric generators.

(d) Lubricating oil is used as a lubricant.

(e) Bitumen Paints are used in road surfacing.

Q.39. What is the major cause of air pollution? Write the various tips for minimizing the wastage of petrol/diesel while driving vehicles.

Burning of fossil fuels is the major cause of air pollution. Burning of fossil fuels affects the environment because they release carbon dioxide and other harmful gases such as Sulphur dioxide, nitrogen oxides and carbon monoxides. These gases trap heat in the earth’s atmosphere and causes global warming which contributes to global climate change. It is therefore necessary that we use these fuels only when absolutely necessary. This will result in better environment, smaller risk of global warming and their availability for a longer period of time. In India, the Petroleum Conservation Research Association (PCRA) advises people how to save petrol or diesel while driving. Their tips are:

• Drive at a constant and moderate speed as far as possible
• Switch off the engine at traffic lights or at a place where you have to wait,
• Make sure there is correct tyre pressure, and
• Ensure regular maintenance of the vehicle.

Q.40. Why should we use fossil fuels only when absolutely necessary?

Burning of fossil fuels affects the environment due to the release carbon dioxide and other harmful gases such as Sulphur dioxide, nitrogen oxides and carbon monoxides. These gases trap heat in the earth’s atmosphere and causes global warming which contributes to global climate change. It is therefore necessary that we use these fuels only when absolutely necessary. It took millions of years for the dead organisms to get converted into these fuels. On the other hand, the known reserves of these fuels will last only a few hundred years. It is therefore, necessary to conserve these natural resources. This will also result in better environment, smaller risk of global warming and their availability for a longer period of time.

Q.41. State (a) two uses of kerosene, and (b) two uses of paraffin wax.

Kerosene is used as a fuel for stoves, lamps and for jet air crafts.

Paraffin wax is used in ointments, candles and Vaseline etc.

Q.42. (a) What is meant by inexhaustible natural resources? Name two inexhaustible natural resources.
(b) What is meant by exhaustible natural resources? Name any two exhaustible natural resources.

(a) The resources which are present in unlimited quantity in nature and are not likely to be exhausted by human activities are known as inexhaustible natural resources. For example, sunlight and air are inexhaustible natural resources.
(b) The resources which are present in a limited amount in nature are known as exhaustible natural resources. They can be exhausted by human activities. Examples of these resources are forests, wildlife, minerals, coal, petroleum, natural gas etc.
Examples: Forests, wildlife, minerals, coal, petroleum, natural gas etc.
It is, therefore, necessary that we use these fuels only when absolutely necessary. It took millions of years for the dead organisms to get converted into coal, petroleum, natural gas etc.

Q.43. (a) What are fossil fuels? Name three fossil fuels.
(b) Describe how, fossil fuels were formed.

(a) The exhaustible natural resources which are formed from the dead remains of living organisms or fossils are known as fossil fuels. For example, coal, petroleum and natural gas are fossil fuels. The resources are present in limited amount in nature and are known as exhaustible natural resources. They can be exhausted by human activities.

(b) The fossil fuel such as coal is formed from the remains of dead vegetation. Earth had dense forests in low lying wetland areas about 300 million years ago. Due to natural processes, like flooding, these forests got buried under the soil. Due to soil deposition over these dead plants, they were compressed. The temperature also increased as they sank deeper and deeper. Under high pressure and high temperature, dead plants got slowly converted to coal. As coal contains mainly carbon, the slow process of conversion of dead vegetation into coal is called carbonisation. Since it was formed from the remains of vegetation, coal is also called a fossil fuel.

The fossil fuel such as petroleum is formed from the dead animals under the sea. As these organisms died, their bodies settled at the bottom of the sea. They got covered with layers of sand and clay. Over millions of years, in the absence of air, with high temperature and high pressure, these the dead organisms were transformed into petroleum and natural gas.

Q.44. (a) What is petroleum? Where does petroleum occur?

(b) Describe the process of formation of petroleum.

(a) The exhaustible natural resources which are formed from the dead remains of living organisms or fossils are known as fossil fuels. For example, coal, petroleum and natural gas are fossil fuels. The fossil fuel such as petroleum is formed from the dead animals under the sea. As these organisms died, their bodies settled at the bottom of the sea.

They got covered with layers of sand and clay. Over millions of years, in the absence of air, with high temperature and high pressure, these the dead organisms were transformed into petroleum and natural gas. The main constituents of petroleum are petroleum gas, petrol, diesel, lubricating oil, paraffin wax and kerosene. Petroleum can be extracted from under the sea bed. It can be extracted with giant drilling machines. The layer containing petroleum oil and gas is above that of water.

(b) The fossil fuel such as petroleum is formed from the dead animals under the sea. As these organisms died, their bodies settled at the bottom of the sea. They got covered with layers of sand and clay. Over millions of years, in the absence of air, with high temperature and high pressure, these the dead organisms were transformed into petroleum and natural gas.

Q.45. (a) What are petrochemicals? Name any two petrochemicals.
(b) Why are petro-chemicals so important?

(a) The fossil fuel such as petroleum is formed from the dead animals under the sea. As these organisms died, their bodies settled at the bottom of the sea. They got covered with layers of sand and clay. Over millions of years, in the absence of air, with high temperature and high pressure, these the dead organisms were transformed into petroleum and natural gas. Many useful substances are obtained from petroleum and natural gas. These are termed as ‘Petrochemicals’. These are used in the manufacture of detergents, fibres such as polyester, nylon, acrylic etc., polythene and other man-made plastics.

(b) Many useful substances are obtained from petroleum and natural gas. These are termed as ‘Petrochemicals’. These are used in the manufacture of detergents, fibers such as polyester, nylon, acrylic etc., polythene and other man-made plastics. Hydrogen gas obtained from natural gas is used in the production of fertilizers such as urea. Due to its great commercial importance, petroleum is also called ‘black gold’.

Q.46. Which one of the following is not a fossil fuel?
(a) Petrol
(b) Coke
(c) Charcoal
(d) Coal

Correct Answer is option (c)

Charcoal is mostly pure carbon which is made by cooking wood in a low oxygen environment. This process can take days and burns off volatile compounds such as water, methane, hydrogen, and tar.

Petrol, coke and coal are fossil fuels which are formed from the dead remains of living organisms or fossils.

Q.47. The major component of LPG is:
(a) Hydrogen
(b) Carbon monoxide
(c) Methane
(d) Butane

Correct Answer is option (d)

The full form of LPG is Liquefied petroleum gas. It is also referred as propane or butane. It is flammable and is used as fuel in heating appliances, cooking equipment and vehicles.

Q.48. Which is the major component of CNG?
(a) Ethane
(b) Propane
(c) Methane
(d) Butane

Correct Answer is option (a)

CNG consists primarily of methane but also contains ethane, propane and heavier hydrocarbons. It also contains small amounts of nitrogen, carbon dioxide, hydrogen sulphide and very little amount of water.

Q.49. The gas which occurs above the petroleum oil trapped under the rocks is called:
(a) Biogas
(b) Petroleum gas
(c) Natural gas
(d) Coal gas

Correct Answer is option (b)

Petroleum can be extracted from under the sea bed. It can be extracted with giant drilling machines. The layer containing petroleum oil and gas is above that of water.

Q.50. Which of the following is being used as a source of hydrogen gas needed to manufacture fertilizers?
(a) Biogas
(b) Natural gas
(c) Coal gas
(d) Petroleum gas

Correct Answer is option (b)

The full form of CNG is compressed natural gas. Natural gas is a very important fossil fuel because it is easy to transport through pipes. It can be used as a fuel in homes and factories. It is also used as a starting material for the manufacture of a number of chemicals and fertilizers.

Q.51. One of the following is not an exhaustible source of energy. This one is:
(a) Natural gas
(b) Petroleum gas
(c) Coal gas
(d) Biogas

Correct Answer is option (d)

Biogas can be produced from raw materials such as agricultural waste, manure, plant material, green waste or food waste. It is a renewable source of energy. Natural gas, coal gas and petroleum gas are fossil fuels and are nonrenewable sources of energy.

Q.52. The slow process by which the large land plants and trees buried deep under the earth have become coal is called:
(a) Carbonation
(b) Carburetion
(c) Carbonisation
(d) Carbocation

Correct Answer is option (c)

Carbonisation is the process by which plant material or vegetation buried deep under the earth was slowly converted into coal. Since, coal was formed from the remains of vegetation, it is also known as fossil fuel.

Q.53. Which of the following is used as a reducing agent in the extraction of iron metal?
(a) Coal
(b) Bitumen
(c) Charcoal
(d) Coke

Correct Answer is option (d)

Coke is a tough, porous and black substance. It is almost pure form of carbon. It is used as a reducing agent in the extraction of metals. It is used in the manufacture of steel and in the extraction of many metals.

Q.54. Which of the following is usually referred to as ‘black gold’?

(a) Coke

(b) Coal tar

(c) Petroleum

(d) Coal

Correct Answer is option (c)

Many useful substances are obtained from petroleum and natural gas. These are termed as ‘Petrochemicals’. Due to its great commercial importance, petroleum is also called ‘black gold’.

Q.55. The various compounds present in coal tar are separated by the process of:
(a)  Simple distillation
(b)  Destructive distillation
(c)  Fractional distillation
(d)  Fractional crystallization

Correct Answer is option (c)

Coal tar is a mixture of about 200 substances. It is a black, thick liquid with unpleasant smell. Synthetic dyes, drugs, perfumes, plastics and paints. Naphthalene balls used to repel moths and other insects are also obtained from coal tar.

Q.56. Which of the following is not obtained as a fractional during the refining of petroleum?
(a) Kerosene
(b) Natural gas
(c) Lubricating oil
(d) Bitumen

Correct Answer is option (b)
Natural gas is a fossil fuel other than coal and petroleum. Petroleum can be extracted with giant drilling machines. The layer containing petroleum oil and natural gas is above that of water.

Q.57. Which one of the following is an inexhaustible natural resource?
(a) Coal
(b) Petroleum
(c) Water
(d) Forests

Correct Answer is option (c)
Water is an inexhaustible natural resource because it is available abundantly in nature.

Q.58. The substances W is a fossil fuel. It occurs deep below the ground in certain areas of the earth. Another fossil fuel X is found trapped above the deposits of W. when W is subjected to a process called Y, then a number of different products are collected at different temperature ranges which are put to different uses. A special grade of product z obtained in this way is used an aviation fuel in jet aero planes.
(a) What are (i) W, and (ii) X
(b) what is the physical state of (i) W, and (ii) X?
(c) Name the process Y?
(d) Name the product Z?

(a) The substance W is Petroleum and substance Y is Natural gas. Natural gas is a fossil fuel other than coal and petroleum. Petroleum can be extracted with giant drilling machines. The layer containing petroleum oil and natural gas is above that of water.

(b) The physical state of W is a liquid. Petroleum is a dark oily liquid. It has an unpleasant odor. It is a mixture of various constituents such as petroleum gas, petrol, diesel, lubricating oil, paraffin wax, etc.

The physical state of X is Gas. Natural gas is a fossil fuel other than coal and petroleum. Natural gas is a very important fossil fuel because it is easy to transport through pipes. Natural gas is stored under high pressure as compressed natural gas (CNG). It can be used as a fuel in homes and factories. It is also used as a starting material for the manufacture of a number of chemicals and fertilizers.

(c) Process Y is known as Fractional distillation. It is the process of separation of a mixture into its components, by the difference in their boiling points. Mixture is heated which causes one or more components to vaporize at different temperatures. The process of separating the various constituents or fractions of petroleum is known as refining. It is carried out in a petroleum refinery.

(d) The product Z is Kerosene. Kerosene is one of the constituent of petroleum. It is a fossil fuel. It is used as a fuel for stoves, lamps and for jet air crafts.

Q.59. The material A is fossil fuel which is extracted from the earth. It is said to be formed from the buried, large land plants by a very slow process B. when A is heated in the absence of air in a process called C, then it gives three products D, E and F. The product D is used as a reducing agent in the extraction of metals, the product E is used as an industrial fuel whereas the product F has been traditionally used for metallic the roads.
(a) What could material A be?
(b) What is (i) physical state, and (ii) colour, of A?
(c) Name the processes (i) B, and (ii) C.
(d) What are (i) D, (ii) E, and (iii) F?

(a) The material A is Coal.

Coal is a fossil fuel. It was formed by the process of carbonisation. Carbonisation is the process by which plant material or vegetation buried deep under the earth was slowly converted into coal. This is a very slow process and usually takes millions of years.
(b) Coal exists as solid.

It is as hard as stone and is black in colour.
(c) The process B is carbonization.

It is a process by which plant material or vegetation buried deep under the earth was slowly converted into coal. This is a very slow process and usually takes millions of years.

The process C is Destructive distillation.

Destructive distillation is a chemical process of decomposition of a solid by heating it in a closed container. The volatile constituents produced in this process can be separated. Coal is processed in industry to get some useful products such as coke, coal tar and coal gas.
(d) The product D is coke, E is Coal gas and F is Coal tar.
Coal is processed in industry by the process of destructive distillation to get some useful products such as coke, coal tar and coal gas. Coke is a tough, porous and black substance. It is almost pure form of carbon. Coal is a mixture of about 200 substances. It is a black, thick liquid with unpleasant smell. Coal gas is obtained during the processing of coal to get coke.

Q.60. The fossil fuel P is formed under the earth by the decomposition of vegetable matter lying under water by the action of anaerobic bacteria. The major component of fuel P is Question The fossil fuel P is used as a source of gas R needed to manufacture nitrogenous fertilizers. When P is filled in metal cylinders and used as a fuel in motor vehicles, it is called S. What are P, Q, R and S?

• The fossil fuel P is known as Natural Gas. Natural gas is a very important fossil fuel because it is easy to transport through pipes. Natural gas is stored under high pressure as compressed natural gas (CNG). It can be used as a fuel in homes and factories. It is also used as a starting material for the manufacture of a number of chemicals and fertilizers.
• The substance Q is Methane. It is the primary component of Natural gas. Natural gas also contains ethane, propane and heavier hydrocarbons.
• The substance R is Hydrogen. Natural gas is used in the manufacture of fertilizers and is used as a source of hydrogen.
• The substance S is Compressed natural gas also known as CNG. Natural gas is a very important fossil fuel because it is easy to transport through pipes. Natural gas is stored under high pressure as compressed natural gas (CNG). It is advantageous to use CNG as a fuel because it is less polluting than petrol. It is a clean burning fuel. It produces 45% less hydrocarbons than petrol.