Coal and Petroleum
Class 8 Science - CBSE Guess and Guide | NCERT Questions Bank
NCERT answers for CBSE Sample Questions - Class 8 Science Chapter 5 Coal and Petroleum
Question.1: What is pure form of carbon?
Question.2: What are natural resources? How many types of natural resources are available in nature?
Answer: Resources which are obtained from nature are called Natural Resources. On the basis of availability of these resources (materials) can be divided into two types:
1. Inexhaustible Natural Resources - natural resources which cannot be finished by human activities like - sunlight, air
2. Exhaustible Natural Resources - are those resources which are present in limited quantity and may be finished by human activities like - wildlife, coal, petroleum.
Question.3: What are inexhaustible natural resources? Give two examples of inexhaustible natural resources.
Answer: See answer of above question.
Question.4: What is coal tar?
Answer: Coal Tar is a black liquid that is produced during destructive distillation of coal. Coal Tar has an unpleasant smell. Earlier coal tar was used for metalling the roads which. Now coal tar is mainly used to produce many types of industrial products, consumables.
Question.5: What are exhaustible natural resources? Give two examples of exhaustible natural resources.
Answer: See answer of above question no. 2.
Question.6: What is Petroleum? Write a short note on Petroleum.
Answer: Petroleum is an exhaustible, natural fossil fuel which is extracted from beneath the surface of the earth. Petroleum was formed from the dead bodies of sea organisms which got buried under the sea bed. Over millions of years, in absence of air, under high temperature and pressure these bodies got transformed into petroleum and natural gas.
Petroleum is a dark, oily liquid with some unpleasant odour. It has various useful constituents like - petroleum gas (LPG), petrol, kerosene, diesel, lubricating oil, paraffin wax, bitumen, etc. which are separated from it by the process known as Fractional Distillation.
Due to its high commercial importance petroleum is known as “Black Gold”.
Question.7: What are fossil fuels?
Answer: Those fuels which got formed by the decomposition of the dead remains of living organisms for a long period of time are called Fossil Fuels. Examples of fossil fuels - coal and petroleum.
Question.9: Define and differentiate between Coal and Coal Gas. [Write short notes on Coal and Coal Gas.]
Answer: Coal is a natural, exhaustible fossil fuel which is found under the surface of the earth. Coal has formed from the dead vegetation over hundreds of millions years through Carbonisation. It is a black, hard solid material. When heated in air it burns and produces mainly carbon dioxide. Coal is mainly used as a fuel in various industries. Several other products like - coke, coal-tar, coal gas etc. obtained after processing coal, are further used for various purposes. In thermal power plants coal is used to produce electricity. In India coal is found mainly in Bihar, Jharkhand, West Bengal and MP.
Coal Gas is a fuel which is obtained during the processing of coal to get coke. Many years ago coal gas was used in America and Britain for street-lighting.
Question.10: What is Petroleum Refining?
Answer: The extraction process in which different constituents of petroleum are separated, known as Fractional Distillation, is also known as Petroleum Refining.
Question.11: Name three products obtained from Petroleum Refining along with their uses.
Answer: Three products obtained from Petroleum Refining and their uses -
L.P.G: Liquefied Petroleum Gas, used as domestic fuel.
Kerosene: Used as fuel for burning in stoves, lamps, automobiles.
Petrol: As fuel for light vehicles, aviations, dry cleaning of fabrics.
Question.12: What is carbonization?
Answer: The slow process of conversion of dead vegetation into coal is called Carbonisation.
Question.13: Which gas is mainly released when coal is burnt?
Answer: Carbon dioxide.
Question.14: To which process coal is put to get some useful products?
Answer: Destructive distillation.
Question.15: What is destructive distillation?
Answer: Burning coal in absence of oxygen to get coke and other useful products is called Destructive Distillation.
Question.16: Why cannot we prepare petroleum in our laboratories?
Answer: Petroleum was formed in hundreds of millions of years by conversion of dead organisms (plants and animals) buried under the surface of the earth under high temperature and pressure conditions.
Such conditions necessary for conversion of dead bodies into fossil fuel cannot be artificially created in laboratories and therefore, we cannot we prepare petroleum in our laboratories.
More study from Chapter 5, Class 8 NCERT Science