Lakhmir Singh & Manjit Kaur: Coal And Petroleum- 1 | Lakhmir Singh & Manjit Kaur Solutions: Class 8 Science PDF Download

Q.1. Name three useful products of coal.

The three useful products of coal are following:

• Coke: It is a tough, porous and black substance. It is almost pure form of carbon.
• Coal tar: It is a mixture of about 200 substances. It is a black, thick liquid with unpleasant smell.
• Coal gas: It is obtained during the processing of coal to get coke.

Q.2. Which product of coal is used as a reducing agent in the extraction of metals?

Coke 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.3. Name the process by which plant material (or vegetation) buried deep under the earth was slowly converted into coal.

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.4. Name the product of coal which is thick black liquid having an unpleasant smell.

Coal tar is the product of coal which is a thick black liquid having an unpleasant smell. It is a mixture of about 200 substances.

Q.5. Name any five substances used in everyday life which are manufactured starting from the products of coal tar.

Substances used in everyday life which are manufactured starting from the products of coal tar are following:

Synthetic dyes, drugs, perfumes, plastics and paints. Naphthalene balls used to repel moths and other insects are also obtained from coal tar.

Q.6. Name an important source from which naphthalene balls are obtained.

Naphthalene balls used to repel moths and other insects are obtained from coal tar.

Q.7. Which substance is used for metalling the roads these days in place of coal tar?

Bitumen, a petroleum product, is used in place of coal-tar for metalling the roads.

Q.8. Name the most common fuel used in light motor vehicles.

Petrol is used as a fuel in light motor vehicles such as motor cycles, scooters and cars.

Q.9. Name the fuel which is used in jet aircraft engines.

Kerosene is used as fuel in jet aircraft engines.

Q.10. Name the petroleum product used to drive heavy vehicles.

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

Q.11. Name the petroleum product which is commonly used for electric generators.

Diesel is used as a fuel for electric generators.

Q.12. What is the full form of LPG?

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.13. Is it possible to extract petroleum from under the sea bed?

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.14. What is the full form of CNG?

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. Natural gas is stored under high pressure as compressed natural gas (CNG).

Q.15. Name the major component of natural gas.

Natural gas consists of 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.16. Name any two places in India where natural gas is found.

India has huge reserves of natural gas. It has been found in Tripura, Rajasthan, Maharashtra and in the Krishna Godavari delta.

Q.17. Name a fossil fuel other than coal and petroleum.

Natural gas is a fossil fuel other than coal and petroleum. Natural gas consists of ethane, propane and heavier hydrocarbons.

Q.18. Name two places in India where coal is found.

India has abundant domestic reserves of coal. Coal can be found in Jharkhand and West Bengal.

Q.19. Name the petroleum product used for surfacing of roads.

Bitumen is used for the surfacing of roads.

Q.20. Name any four places in India where petroleum is found.

In India, oil is found in Assam, Gujarat, Mumbai High and in the river basins of Godavari and Krishna.

Q.21. Write the full form of PCRA.

The full form of PCRA is Petroleum Conservation Research Association. It advises people how to save petrol/diesel while driving.

Q.22. State whether the following statements are true or false:
(a) Coke is almost pure from carbon.
(b) Coal tar is a mixture of various substances.
(c) Kerosene is not a fossil fuel.
(d) CNG is more polluting than petrol.
(e) Fossil fuels can be made in the laboratory.

(a) This statement is True.
It is a tough, porous and black substance. It is almost pure form of carbon.
(b) This statement is True.
Coal tar is the product of coal which is a thick black liquid having an unpleasant smell. It is a mixture of about 200 substances.
(c) This statement is False.
Kerosene is a fossil fuel. It is used as a fuel for stoves, lamps and for jet aircrafts.
(d) This statement is False.
CNG is less polluting than petrol. It is a clean burning fuel. It produces 45% less hydrocarbons than petrol.
(e) This statement is False.
The formation of fossil fuels is a very slow process. These are formed under very high pressure and high temperature. The conditions for their formation cannot be created in the laboratory.

Q.23. Fill in the following blanks with suitable words:
(a) Fossil fuels are _______ and _______
(b) Coal contains mainly _______
(c) The slow process of conversion of dead vegetation into coal is called _______
(d) The process of separation of different constituents from petroleum is called
_______
(e) The least polluting fuel for vehicles is _______
(f) The burning of fossil fuels causes air_______ and also leads to global _______

(a) The correct Answer: is _______ Coal, petroleum and _______ natural gas.

Coal, Petroleum and natural gas are formed from the dead remains of living organisms or fossils. So, these are all known as fossil fuels.

(b) The correct Answer: is _______ carbon.

Coal is formed from the remains of vegetation, it is also called a fossil fuel. Being produced from vegetation it mainly contains carbon.

(c) The correct Answer: is _______ Carbonisation.

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.

(d) The correct Answer: is _______ refining.

Petroleum is a mixture of various constituents such as petroleum gas, petrol, diesel, lubricating oil, paraffin wax, etc. The process of separating the various constituents or fractions of petroleum is known as refining. It is carried out in a petroleum refinery.

(e) The correct Answer: is _______ CNG.

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. Natural gas is stored under high pressure as compressed natural gas (CNG).

(f) The correct Answer: is _______ pollution; warming.

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.

Q.24. Explain why, fossil fuels are exhaustible natural resources.

The amount of fossil fuels is very limited in nature. They can be exhausted by human activities. The formation of fossil fuels is a very slow process. These are formed under very high pressure and high temperature. For example, coal, petroleum and natural gas are fossil fuels. Coal 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.

Q.25. Describe how coal was formed. What is this process called?

Coal was formed millions and millions of years ago in swampy forests where some plants died and some grew simultaneously. As the years passed, the layers of dead plants collected one over the other and formed thick layers. With changing weather conditions, more plants grew and the layers of dead plants continued to form deep. Coal is a fossil fuel. The heat and the pressure produced physical and chemical changes in the layers which resulted in the rich carbon content and forced the oxygen into the environment. This rich carbon content became as coal. This process of forcing the oxygen out and leaving behind carbon content was called as carbonisation. In other words, 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.

Q.26. What is happens when coal is heated in air? State the uses of coal.

When heated in air, coal burns and produces mainly carbon dioxide gas. Coal can be processed in industry to get some useful products such as coke, coal tar and coal gas. Coal is used as a fuel in industries and was used to cook food. It was used in railway engines to produce steam to run the engine. It is used in thermal power plants to produce electricity.

Q.27. State the uses of coke.

Coke is a very useful product of coal. It 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 also used in the manufacture of steel and in the extraction of many metals.

Q.28. What are the constituents of coal gas? State one use of coal gas.

Coal gas is a product of coal. It is obtained during the processing of coal to get coke. Coal gas contains a variety of gases like hydrogen, carbon monoxide, methane and some volatile hydrocarbons. It also contains small quantities of gases such as carbon dioxide and nitrogen. It is used as a fuel in many industries situated near the coal processing plants.

Q.29. What are the major products (or fractions) of petroleum refining? Give one use of each petroleum product.

The process of separating the various constituents or fractions of petroleum is known as refining. It is carried out in a petroleum refinery. The main products of petroleum refining are petroleum gas, petrol, diesel, lubricating oil, paraffin wax and kerosene. Following are the uses of petroleum products:

• Petroleum gas is used as fuel for home and industry.
• Petrol is used as a Motor fuel, aviation fuel and solvent for dry cleaning.
• Diesel is used as a fuel for heavy motor vehicles and electric generators.
• Lubricating oil is used as a lubricant.
• Kerosene is used as a fuel for stoves, lamps and for jet aircrafts.
• Paraffin wax is used in ointments, candles and Vaseline etc.
• Bitumen Paints are used in road surfacing.

Q.30. What are the advantages of using natural gas (or CNG) as a fuel?

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 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 directly for burning in homes and factories where it can be supplied through pipes.