Ncert solutions science class 8 Solutions for Chapter 5 coal and petroleum

Various materials which are obtained from nature are called natural resources. Which of the following is not a natural resource?

(a) minerals

(b) water

(c) soil

(d) plastic

Q1) What are the advantages of using CNG and LPG as fuels?

What are the advantages of using CNG and LPG as fuels?

Q3) Describe how coal is formed from dead vegetation. What is this process

called?

Air is a natural resource and cannot be exhausted by human activities. It is known as inexhaustible natural resource. Which of the following is another inexhaustible natural resource?

(a) coal

(b) petroleum

(c) sun-light

(d) minerals

Q2) Name the petroleum product used for surfacing of roads.

Which of the following is a pair of exhaustible natural resources.

(a) coal and soil

(b) air and sun-light

(c) water and petroleum

(d) wild life and minerals

Describe how coal is formed from dead vegetation. What is this process called?

Q4) Fill in the blanks.

a) Fossil fuels are _________, ___________ and ____________.

b) Process of separation of different constituents from petroleum is called ____________.

c) Least polluting fuel for vehicle is ____________.

Fill in the blanks.

(a) Fossil fuels are ____________, ____________, and ____________ .

(b) Process of separation of different constituents from petroleum is called _____________ .

(c) Least polluting fuel for a vehicle is ______________ .

Coal is processed in industries to get some useful products. Which of the following is not obtained from coal?

(a) coke

(b) coal tar

(c) coal gas

(d) CNG

Exhaustible natural resources are:

(a) unlimited in quantity.

(b) not dependent on nature.

(c) limited in quantity.

(d) not exhausted by human activities.

Q5) Tick True/False against the following statements.

(a) Fossil fuels can be made in the laboratory. (T/F)

(b) CNG is more polluting fuel than petrol. (T/F)

(c) Coke is almost pure form of carbon. (T/F)

(d) Coal tar is a mixture of various substances. (T/F)

(e) Kerosene is not a fossil fuel. (T/F)

Tick True/False against the following statements.

(a) Fossil fuels can be made in the laboratory. (T/F)

(b) CNG is more polluting fuel than petrol. (T/F)

(c) Coke is the almost pure form of carbon. (T/F)

(d) Coal tar is a mixture of various substances. (T/F)

(e) Kerosene is not a fossil fuel. (T/F)

Explain why fossil fuels are exhaustible natural resources.

Q6) Explain why fossil fuels are exhaustible natural resources.

Fossil fuels are obtained from:

(a) remains of non-living materials.

(b) dead remains of birds only.

(c) dead remains of insects only.

(d) dead remains of living organisms.

Q7) Describe characteristics and uses of coke.

Describe the characteristics and uses of coke.

Coal is formed from the remains of

(a) vegetation only

(b) animals only

(c) both vegetation and animals

(d) neither vegetation nor animals

Explain the process of the formation of petroleum.

Which substance is formed by the carbonisation of dead vegetation?.

(a) coal

(b) coke

(c) coal gas

(d) coal tar

Q8) Explain the process of formation of petroleum.

Q9) The following Table shows the total power shortage in India from 1991–1997. Show the data in the form of a graph. Plot shortage percentage for the years on the Y-axis and the year on the X-axis.

Naphthalene balls are obtained from coal tar and are used as

(a) mosquito repellant

(b) honey bee repellant

(c) moth repellant

(d) snake repellant

The following table shows the total power shortage in India from 1993–1999. Show the data in the form of a graph. Plot shortage percentage for the years on the Y-axis and the year on the X-axis.

Which of the following is not a constituent of petroleum?

(a) paraffin wax

(b) lubricating oil

(c) petrol

(d) coke

Petroleum was formed from organisms:

(a) living on the land

(b) living on the plants

(c) living in the sea

(d) living on the rocks

Choose the incorrect statement from the following:

(a) It is difficult to transport natural gas through pipes.

(b) The disadvantage of natural gas is that it can not be used directly for burning in homes.

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

(d) Natural gas cannot be used for power generation.

You are provided with a mixture of petroleum and water. Can you suggest a method to separate the two?

What does CNG stand for and why is it considered to be a better fuel than petrol?

Name the petroleum product used as fuel for stoves, lamps, and jet aircraft.

Fill in the blanks in the following sentences.

(a) Coal is one of the ________ used to cook food.

(b) When heated in air, coal burns and produces mainly ________ gas.

(c) Coal tar is a black, thick ________ with an ________ smell.

(d) Petroleum, ________ and ________ are fossil fuels.

(e) Forests and coal are ________ natural resources.

The underlined words in the following sentences have been jumbled up. Write them in their correct form.

(a) Loca is obtained from mines.

(b) Umpetlore is a fossil fuel.

(c) Rineryfe is a place where various fractions of petroleum are separated.

(d) Keenrose is a fuel used in jet crafts.

(e) Nutsgilh is an example of inexhaustible natural resources.

Fill in the blanks.

(a) The slow process of conversion of dead vegetation into coal is called__.

(b) Coal and petroleum are formed from the dead remains of organisms and are known as __________.

(c) The black thick liquid with __________ smell is known as coal tar.

(d) During the processing of coal to get a coke, coal tar, and __________ are also obtained.

(e) The process of separating the various constituents of petroleum is known as __________.

(f) Excessive burning of fossil fuels is a major cause of __________.

Write True/False against the following statements.

(a) Oxygen in the air is an exhaustible natural resource.

(b) Resources that are present in unlimited quantity in nature are called exhaustible natural resources.

(c) Wildlife is an exhaustible natural resource.

(d) Under high temperature and pressure, dead plants get slowly converted to coal.

(e) CNG is less polluting fuel than petrol and diesel.

Sunlight and air are inexhaustible natural resources. Comment.

Some natural resources are given in a box. Classify them into the exhaustible and inexhaustible natural resources.

air, coal, natural gas, sunlight, petroleum, minerals, forests, oxygen.

Write two important uses of coke.

Write the characteristics and some important uses of coal.

Look at Fig. where petroleum and natural gas deposits are shown. Why do we find the oil layer above the water layer?

Fill in the blanks and complete the story.

About 300 million years ago the earth had dense ________ in low lying wetland areas. Due to natural processes, like ______, these forests got burried under the ________. As more ________ deposited over them, they were compressed. The ________ also rose as they sank deeper and deeper. Under high ________ and high ________, dead plants got slowly converted into coal.

Match the items given in Column I with the items of Column II.

Name the products obtained and their uses when coal is processed in industry.

We say fossil fuels will last only for a few hundred years. Comment.

We read in newspapers that the burning of fuels is a major cause of global warming. Explain why.

While driving what are the tips we must follow to save petrol/ diesel/natural gas?

Imagine that all the exhaustible natural resources are exhausted by human activities. Do you think the survival of living beings would be possible.? If yes, why?, If not, why not?

Why petrol is an exhaustible natural resource, whereas sunlight is not? Explain.

Write some important uses of the various constituents of petroleum.

Coal reserves are said to be enough to last for another hundred years. Do you think we need to worry in such a case? Why or why not?

What steps would you suggest for the judicious use of fossil fuels?

Complete the crossword Fig. with the help of the clues:

Across

1. Fuels obtained form dead remains of living organisms. (6,5)

2. A process by which the various constituents of petroleum are separated. (8)

3. A porous black substance obtained form coal. (4)

4. Another name for motor fuel. (6)

Down

5. The substance obtained by carbonization. (4)

6. Fuel for heavy motor vehicles. (6)

7. A petroleum product used for road surfacing. (7)

8. Dead remains of sea animals got converted into it. (9)