Saturday, June 24, 2017

CBSE Class 8 - Science - Coal and Petroleum (Q and A) (#cbseNotes)

Coal and Petroleum
(NCERT Exemplar  Q & A)

CBSE Class 8 - Science - Coal and Petroleum (Q and A) (#cbseNotes)
Petroleum Refinery

Question 1: You are provided with a mixture of petroleum and water. Can you suggest a method to separate the two?

Answer: Decantation

Question 2: What does CNG stand for and why is it considered to be a better fuel then petrol?

Answer: CNG stands for compressed natural gas. It is considered to be a better fuel because it is less polluting.

Question 3: Name the petroleum product used as fuel for stoves, lamps and jet aircrafts.

Answer: Kerosene is used as fuel for stove,lamps and jet aircrafts.

Question 4: Fill in the blanks in the following sentences.

1. Coal is one of the ________ used to cook food.
2. When heated in air, coal burns and produces mainly _________ gas.
3. Coal Tar is a black, thick - with an ________ smell.
4. Petroleum, ______ and _______ are fossil fuels.
5. Forest and coal are _________ natural resources.

1. Fuel
2. Carbon dioxide
3. Liquid ,unpleasant
4. Coal, natural gas
5. Exhaustible

Question 5: The underlined words in the following sentences have been jumbled up. Write them in their correct form.

1. LocA is obtained from mines.
2. umpetlore is a fossil fuel.
3. Rineryfe is a place where various fractions of Petroleum are separated.
4. Keenrose is a fuel used in jet crafts.
5. Nutsgilh is an example of inexhaustible natural resources.

1. Coal
2. Petroleum
3. Refinery
4. Kerosene
5. Sunlight

CBSE Class 8 - Science - Coal and Petroleum (Q and A) (#cbseNotes)
coal miner

Question 6: Fill in the blanks.

1. The slow process of conversion of Dead vegetation into coal is called ____________

2. Coal and petroleum are formed from the dead remains of organisms and are known as __________.

3. The Black thick liquid with __________ smell is known as Coal Tar.

4. During the processing of coal to get coke, coal Tar and __________ are also obtained.

5. The process of separating the various constituents of Petroleum is known as _____________.

6. Excessive burning of fossil fuel is a major cause of _______________.

1. Carbonisation
2. Fossil fuels
3. Unpleasant
4. Coal gas
5. Refining
6. Air pollution

Question 7: Write True or False against the following statements:

1. Oxygen in air is an exhaustible natural resource.

2. Resources which are present in unlimited quantity in nature are called exhaustible natural resources.

3. Wildlife is an exhaustible natural resource.

4. Under High temperature and pressure, dead plants get slowly converted to coal .

5. CNG is less polluting fuel than petrol and diesel.

1. False
2. False
3. True
4. True
5. True

Short Answer Questions

Question 8: Sunlight and air are inexhaustible natural resources. Comment.

Answer: These resources are present in unlimited quantity in nature and are not likely to be exhausted by human activities.

Question 9: Natural resources are given here. Classify them into the exhaustible and inexhaustible natural resources.
Air, coal, natural gas, sunlight, petroleum, minerals, forest, oxygen

Answer: Exhaustible natural resources are coal , natural gas, petroleum, natural gas petroleum minerals, forest. Inexhaustible natural resources are air, sunlight, oxygen

Question 10: Write two important uses of coke

Answer: It is used for extraction of many metals and also for manufacture of Steel.

Question 11: Write the characteristics and some important uses of coal.

Answer: Coal is black in colour and hard as stone. It is one of the fuels used to cook food. Earlier it was used in railway engines to produce stream to run the engine. It is used as fuel in thermal power plants to produce electricity and in various Other industries.

Question 12: 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 buried 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.

Answers: forest, floods, soil, soil, temperature, pressure, temperature

Long Answer Questions

Question 13: Name the products obtained and their uses when coal is processed in industry.

Answer: Coal when processed in industry gives Coke, Coal Tar and coal gas. It is used in the manufacture of Steel and in extraction of many metals. Coal Tar is used as starting material for manufacturing various substances such as synthetic dyes, drugs, explosive, perfumes, paints . Coal gas is used as fuel.

Question 14: We say fossil fuels will last only for a few hundred years. comment.

Answer: It takes a very long time for the formation of fossil fuels. It also require specific conditions and it doesn't happen quite often. Therefore, their limited stock will last only for a few hundred years.

Question 15: We read in newspaper that burning of fuel is a major cause of global warming. Explain why.

Answer: It is related to global warming due to formation of carbon dioxide and some other gases. Carbon dioxide traps sun's heat and raises the temperature of the earth.

Question 16 while driving what are the tips we must follow to save petrol oblique diesel oblique natural gas?

1. Ensure correct tyre pressure.
2. Ensure regular maintenance of the vehicle.
3. Drive at a constant and moderate speed
4. Switch off the engine at traffic lights or at a place where you have  to wait.

Question 17: Why petrol is exhaustible natural resource, whereas sunlight is not? Explain.

Answer: Sunlight is present in unlimited quantity in nature where as it takes millions of years to form  petrol from dead remains of organisms.

Question 18: Mention some important uses of various constituents of Petroleum.

1. Petroleum gas in liquid form LPG is used as fuel for home and industry.
2. Petrol - used as fuel for automobile and aviation.
3. Kerosene - used as fuel for stoves lamps and for Jet aircrafts
4. Diesel - used as fuel for heavy motor vehicles, electric generator.
5. Lubricating oil -  used for lubrication.
6. Paraffin wax - used in ointment candles and vaseline etc.
7. Bitumen -  used in Paints and Road surfacing

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