Class 8 Science Chapter 3 MCQ

Here, all these statements are correct. Hence, your answer will be option [D].

Here, all these statements are correct. Hence, your answer will be option [D].

About 300 million years ago the earth had dense forests in low lying wetland areas. Due to natural processes, like flooding, these forests got buried under the soil. As more soil deposited over them, they were compressed. The temperature also rose 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.

Coke is not a constituent of petroleum. Coke is prepared by heating coal in the absence of air.

Oxygen in air is an exhaustible natural resource. The natural resources which are present in unlimited quantity in nature and are not likely to be exhausted by human activities are called “inexhaustible natural resources”. Examples of inexhaustible natural resources are: sunlight, air, water. They last forever. The resources which are present in a limited quantity in nature and can be exhausted by human activities are called “exhaustible natural resources”. The example of exhaustible natural resources is: coal, petroleum and natural gas, mineral, forest and wildlife etc. They do not last forever.

Paraffin wax is used in ointment, candles, Vaseline etc. Bitumen is used in paints and road surfacing.

Naphthalene balls are used to repel moths and other insects (in stored clothes, etc.)

Sunlight, air and water are the examples of inexhaustible nature resources. There is a never ending in nature and they can be used again and again. But coal, petroleum and natural gas are non-renewable resources of energy. By using or exhausted, no more supply of these fuels will be available in the near future.

Coal is formed by the carbonization of dead vegetation.

Coal gas, coal tar and coke are called products of coal. These products are obtained when coal is heated in the absence of air. This is because if coal is heated in the presence of air, then coal burns to produce mainly carbon dioxide gas and no other useful products obtained. The strong heating of coal in the absence of air is called destructive distillation of coal. And coal gas is a gaseous fuel which is obtained by the strong heating of coal in the absence of air during the process of coal to get coke.

Fossil fuels are obtained from the remains of living organisms (plants and animals) buried under the earth millions of years ago. Note: Coal, Petroleum and Natural gas are fossil fuels.

Bitumen is used for road surfacing. It is also used for water-proofing the roofs of building. Bitumen is used in making black paints.

Exhaustible natural resources are present in limited quantity in nature and can be exhausted by human activities. Note: Coal, petroleum and natural gas, minerals, forest and wildlife, etc. are exhaustible natural resources.

The most common fuel used in homes is liquefied petroleum gas because it is obtained from petroleum and it is liquefied by compression before filling into the gas cylinders. Liquefied Petroleum Gas consists mainly of butane. LPG burns easily and it does not produce any poisonous gas on burning. LPG burns with a smokeless flame and hence does not cause air pollution.

Here, all these statements are correct. Hence, your answer will be option [D].

Here, all these statements are correct. Hence, your answer will be option [D].

Wildlife and minerals are exhaustible natural resources because these resources are present in a limited quantity in nature and can be exhausted by human activities.

The major component of LPG and CNG are butane and methane respectively.

Here, all these statements are correct about fossil fuel. Hence, your answer will be option [D].

Natural gas is stored under high pressure as compressed natural gas. Note: It is easy to transport natural gas through pipes and it can be used directly for burning in homes where it can be supplied through pipes. Natural gas is used for power generation

Sunlight, air and water are the examples of inexhaustible nature resources. There is a never ending in nature and they can be used again and again. But coal, petroleum and natural gas are non-renewable resources of energy. By using or exhausted, no more supply of these fuels will be available in the near future.

Minerals, water and soil are the natural resources but plastic is a man-made material. So, plastic is not a natural resource.

Coal is used to make coke, not Coca-Cola. Coke is an almost pure form of carbon. Coal is important because it can be used as a source of heat energy. Coke is a porous and tough, black solid substance. Coke is prepared by heating coal in the absence of air. Coke is used in the manufacturing of “steel”. Although, coke burns without producing any smoke whereas coal produces a lot of smoke on burning.

Coke is prepared by heating coal in the absence of air. Coke is mainly used as a reducing agent in the extraction of metals. Such as iron, zinc etc. Coke is used in the manufacturing of Steel.

Coal tar is black liquid which have unpleasant smell and obtained from coke. Although, coal tar is a not a single compound, it is a mixture of 200 types of carbon compounds. Such as, benzene, naphthalene, phenol etc.