myclass24
myclass24your class. your pace.
Q&A BANK

every question.
answered.

1,376 answers across CBSE, ICSE, and State boards — Class 1 to 12, every subject.

CBSEICSEState
SUBJECT
CLASS

Filtered results

1,376 TOTAL
ScienceClass 8CBSE

Write some important uses of the various constituents of petroleum.

Soln: Constituents of Petroleum are petroleum gas, petrol, diesel, kerosene, lubricating oil, paraffin wax and Bitumen. Constituents of petroleum Uses Petroleum Gas (LPG) Fuel for home and industry Petrol Used as fuel for light automobiles. Kerosene Fuel for lamps, stoves and jet aircrafts Diesel Used as fuel for large automobiles and electric generators Lubricating oil Used as lubricant for engines Paraffin wax Used in preparation of Ointments, candles, vaseline etc. Bitumen Used in preparation of Paints, road surfacing

ScienceClass 8CBSE

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

Petrol is a fossil fuel which is produced after years of decomposition of buried and plants deep down the earth. For producing petrol we need millions of years. If we use petrol higher than the requirement. Perol will get exhausted. Whereas sun is a continuous and unlimited source of energy. Sun is renewable resource of energy which will not get exhausted.

ScienceClass 8CBSE

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

If all the exhaustible natural resources are exhausted by human activities then survival of living beings would be impossible. Fossil fuels are very important source of energy for us today. On burning fossil fuel and give off heat and light. Heat produced can be used to cook food or to run engines such as automobile engines. It can be used to generate electricity as in powerhouse where the most common fuel used is coal.

ScienceClass 8CBSE

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

Steps to follow while driving to save petrol/ diesel/natural gas Drive at a constant and moderate speed as far as possible, Switch off the engine at traffic lights or at a place where you have to wait, Ensure correct tyre Ensure regular maintenance of the

ScienceClass 8CBSE

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

Burning of fuels lead to release of carbon-di-oxide, carbon-monoxide and SO2 gases. These are the green houses gases that not only increases the air pollution but also contribute for the global warming by trapping radiations from sun.

ScienceClass 8CBSE

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

Fossils fuels take millions of years to get converted into these fuels. Formation of fossil fuels requires specific conditions and it doesn’t happen quite often. Therefore, their limited stock will last only for a few hundred years.

ScienceClass 8CBSE

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

Coke, coal tar and coal gas are obtained when we process coal. Coke is used as reducing agent in the extraction of metals. Coal tar is used as starting material for manufacturing various sustances such as synthetic dyes, drugs, explosives, perfumes, paints etc. Coal gas is used as fuel.

ScienceClass 8CBSE

Match the items given in Column I with the items of Column II. Column I Column II (a) Used for road surfacing (i) Black gold (b) Natural gas (ii) Vaseline and candles (c) Petroleum (iii) Bitumen Paraffin wax (iv) CNG

Soln: Column I Column II Used for road surfacing (iii) Bitumen Natural gas (iv) CNG Petroleum (i) Black gold Paraffin wax (ii) Vaseline and candles

ScienceClass 8CBSE

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.

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

ScienceClass 8CBSE

Write the characteristics and some important uses of coal.

Characteristics of coal. It is as hard as stone and is black in It is Combustible It is a fossil fuel When it is burned in air it releases CO Uses of Coal Coal is one of the fuels used to cook Earlier, it was used in railway engines to produce steam to run the It is also used in thermal power plants to produce Coal is also used as a fuel in various

ScienceClass 8CBSE

Write two important uses of coke.

Important uses of coke are as follows Coke is used as reducing agent in extraction of metal from its Coke is used in the manufacture of steel

ScienceClass 8CBSE

Sunlight and air are inexhaustible natural resources. Comment.

Soln: Sunlight is present in unlimited and they will not get exhausted by any means. Hence Sunlight is inexhaustible natural resources. Some natural resources are given in a Classify them into the exhaustible and inexhaustible natural resources. air, coal, natural gas, sunlight, petroleum, minerals, forests, oxygen. Soln: Exhaustible Inexhaustible coal air natural gas sunlight, petroleum, oxygen. minerals Forests

ScienceClass 8CBSE

Write True/False against the following statements. (a) Oxygen in air is an exhaustible natural resource. (b) Resources which 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.

False Explanation: Oxygen is not an exhaustible natural resource. False, Explanation: Resources which are present in unlimited quantity in nature are called inexhaustible natural resources. True, True,

ScienceClass 8CBSE

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 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 .

The slow process of conversion of dead vegetation into coal is called carbonisation. Coal and petroleum are formed from the dead remains of organisms and are known as fossil fuels. The black thick liquid with unpleasantsmell is known as coal During the processing of coal to get coke, coal tar and coal gasare also The process of separating the various constituents of petroleum is known as refining. Excessive burning of fossil fuels is a major cause of air pollution.

ScienceClass 8CBSE

1. 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 peroleum are separated. (d) Keenrose is a fuel used in jet crafts. (e) Nutsgilh is an example of inexhaustible natural resources.

coal petroleum refinery kerosene sunlight

ScienceClass 8CBSE

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.

Coal is one of the fuel used to cook When heated in air, coal burns and produces mainly Carbon-di-oxide Coal tar is a black, thick liquid with an unpleasant Petroleum, Coal and natural gas are fossil Forests and coal are exhaustible natural

ScienceClass 8CBSE

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

Kerosene is the petroleum product used as fuel for stoves, lamps and jet aircrafts.

ScienceClass 8CBSE

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

CNG stands for compressed natural gas. CNG burns with no smoke hence it does not cause air pollution. CNG does not produce any poisonous gas hence CNG is considered a better fuel than petrol.

ScienceClass 8CBSE

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

Decantation method is used to separate mixture of petroleum and water.

ScienceClass 8CBSE

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.

Soln: Answer is (d) Natural gas cannot be used for power generation. Explanation: Natural gas can be used for power generation hence statement d) is wrong

STILL STUCK?

Get a tutor for just your question.

One-on-one help, verified tutors. Matched within 24 hours.

Get Started →