1. Resources-
ü Resources are anything that has utility and adds value to your life.
ü Air, water, food, plants, animals, minerals, metals, and everything else that exists in nature and has utility to mankind is a ‘Resource’.
ü The value of each such resource depends on its utility and other factors.
ü For example, metals are gold, silver, copper or bronze have economic value; i.e. they can be exchanged for money.
ü However, mountains, rivers, sea or forests are also resources but they do not have economic value.
ü There are two most important factors that can turn any substance into a resource- time and technology.
ü With the help of technology, innovation humans can transform a natural or man-made substance into a resource.
ü Like, minerals, fish or other marine creatures sourced from the sea can be used for our food and medicines.
ü Similarly, time also adds to the value of a resource.
ü For example, fossil deposits of organisms over hundreds of years can turn into fossil fuels.
2. Natural Resources -
ü Anything and everything that is available naturally on earth is a natural resource.
ü We can further divide them into-
n Biotic & Abiotic- Any life form that lives within nature is a Biotic Resource, like humans, animals, plants, etc. In contrast, an abiotic resource is that which is available in nature but has no life; like metals, rocks, and stones. Both biotic and abiotic resources can be renewable or non-renewable.
n Renewable & Non-renewable- Renewable resources are almost all elements of nature which can renew themselves. For e.g. sunlight, wind, water, forests and likewise. While, non-renewable resources, are limited in their quantity. Like fossil fuels and minerals. Though these resources take millions of years to form, they would eventually get over within our lifetime if we use continuously.
n Potential, Developed, and Stock Resources- Natural elements which are already easily available but humans are yet to discover their real power are Potential resources. For example, solar and wind energy are two natural resources, which have a high potential for human life. Though we are using it, we can use these even more in the future once we understand their true potential.
3. Man-Made Resources-
ü When humans use natural things to make something new that provides utility and value to our lives, it is called human-made resources.
ü For instance, when we use metals, wood, cement, sand, and solar energy to make buildings, machinery, vehicles, bridges, roads, etc. they become man-made resources.
ü Likewise, technology is also a man-made resource. Man-made resources are mostly renewable.
ü One can re-build a building or fixed a broken machine.
ü And, because humans have the skills, intelligence, and knowledge, and use technology to transform a natural resource into usable and valuable things, they themselves become a resource. That is what we know as Human Resource.
4. Fuels-
ü A fuel is any substance that release a large amount of energy in the form of heat and light when burned.
ü For example, coal and petroleum are fuels.
ü Fuels can be classified as-
Classification | Definition | Examples |
Solid Fuels | These fuels exist in a solid state at room temperature | For example, coal, firewood, animal dung cakes, charcoal, coke |
Liquid Fuels | These are volatile liquids that produce vapor which burns and produces energy | For example, petrol, diesel, kerosene |
Gaseous Fuels | These are the fuels that exist in the form of a gas or as a mixture of different gaseous fuels. | For example, natural gas, biogas, CNG, coal gas |
5. Applications Of Fossil Fuels-
ü Transportation- Fuels are used to run different vehicles such as cars, trucks, motorcycles, trains, airplanes etc.
ü Cooking- Fuels are needed for cooking. For instance, LPG is used in urban areas while firewood, coal and cattle dung is used in rural areas.
ü Heating- Fuel is also used to generate heat.
ü Electricity Production- Different fuels such as coal, petrol, natural gas and diesel are used to generate electricity in power plants.
ü Industrial usage- Many industries use fuels for different purposes such as producing electricity, running their machinery and heating.
ü Rockets And Other Space Vehicles- Fuels called propellants are used in rockets that help in launching the space vehicles.
6. Characteristics Of Good Fuel-
ü It should produce large amounts of heat with respect to its mass.
ü It should be easy to transport and handle.
ü It should not produce a bad odor.
ü It should be economical.
ü It should be available easily
ü It should not emit poisonous gases on burning.
ü It should be clean and should not produce many ashes.
ü It should not ignite easily at room temperature.
7. Coal
Figure 01- Coal
ü Coal is a fossil fuel formed from dead plant matter over millions of years due to heat and pressure.
Figure 02- Formation of coal
ü Over millions of years, coal is formed through different biological and geological processes on dead and decaying plant matter.
ü Coal mainly contains carbon. The process of conversion of dead vegetation into coal is called carbonisation.
ü Coal consists of hydrogen, carbon and oxygen and sulphur (small amount).
ü Coal is extracted from the ground with a process called mining.
ü Coal mining can be of two types-
n Opencast Mining- Mining in which coal is extracted from near the earth’s surface
n Underground Mining- Mining in which coal is extracted from deep inside the earth’s crust
Figure 04- Types of coal
ü Following are the uses of coal-
n Used as fuel to cook food.
n Used in thermal power plants to produce electricity.
n Used as fuel in various industries.
u Once used as fuel to run steam-powered railway engines.
ü When processed, coal yields coke, coal tar and coal gas which in turn is used by many industries.
Figure 05- Coal products
8. Destructive Distillation-
ü It is a process in which coal is heated at very high temperature in the absence of air to obtain various useful products from it.
ü Different products are obtained through this process like coal gas, coal tar, coke and liquor ammonia.
Q. What are hydrocarbons?
Ans.- Hydrocarbons are the substances that consist of only carbon and hydrogen. Compounds like methane, butane, and hexane are hydrocarbons that are produced on burning of the fossil fuels.
Q. What will happen if the coal reserves get depleted?
Ans.- Coal is being used as a major source of energy in industries as well as rural areas. Not only this, it serves various other purposes like the synthesis of synthetic oil, natural gas, coke, coal tar and coal gas. If the amount of coal gets depleted it would become much difficult for us to produce energy for various purposes. Hence, we must use coal in an efficient way.
Q. What substances are released on the burning of coal?
Ans.- Carbon dioxide, Carbon monoxide, Sulphur Dioxide, Nitrogen, Lead, Arsenic and Mercury.
9. Petroleum
ü The term 'Petroleum' is derived from two words - 'Petra' which means 'rock' and 'oleum' which means 'oil'.
ü It is mined from the rocks present under the Earth.
ü Petroleum, also known as crude oil is a fossil fuel formed from the remains of ancient marine organisms.
How is Petroleum and Natural Gas formed?
Figure 06- Formation of petrol and natural gas
ü When the sea organisms die, their bodies sink to the bottom of the sea. With time, they get covered by the layers of sand and clay.
ü Over millions of years, these remains get transformed in petroleum and natural gas due to high temperature, high pressure, and absence of air.
ü When we dig oil wells, natural gas is above crude oil which in turn is above water. This happens because gas and oil are lighter than water and do not mix with it.
Figure 07- Oil mines in India
Figure 08- Constituents of petroleum
10. Refining of Petroleum Products-
ü Originally, petroleum is a mixture of many things, such as petrol, diesel, petroleum fas, paraffin wax, lubricating oil etc.
ü It is a dark and oily liquid with an unpleasant odor.
ü Refining of petroleum is the process by which different constituents of petroleum are separated.
ü This process takes place in a petroleum refinery.
Q. Why Petroleum is called ‘black gold?
Ans.- Petroleum is called 'black god' because it yields several substances that are commercially successful. The useful substances obtained from petroleum and natural gas are called 'petrochemicals'.
11. Natural Gas
Figure 09- Natural gas
ü Natural gas is a fossil fuel found naturally as a hydrocarbon gas mixture in the oil wells.
ü Its main component is methane but it may also contain varying amounts of other higher alkanes (a group of elements).
ü Gases like carbon dioxide, helium, nitrogen, and hydrogen sulphide are also found in natural gas in small percentages.
Q. Why is Natural Gas important as a fossil fuel?
Ans.- Natural gas is considered important as this fossil fuel can easily be transported through pipes. It is stored as CNG which is used for several purposes and is also used as a starting material for manufacturing many chemicals and fertilizers. Natural Gas does not cause pollution and has high calorific value.
12. Compressed Natural Gas (CNG)-
ü It is the natural gas which is stored under high pressure.
Q. Why is CNG useful?
Ans.- It act as- Fuel to generate power, it is cleaner fuel for transport vehicles (less polluting than petrol and diesel) fuel in homes and industries which can be supplied through pipes. CNG pipeline network already exists in Vadodara in Gujarat, some parts of Delhi and some other places.
Q. Why is CNG considered as a cleaner fuel?
Ans.- Natural gas is considered a better fuel than coal and petroleum because it is cleaner. This means that it results in less amount of pollution that the other fossil fuels. Natural gas emits 50% less carbon dioxide, sulphur and nitrogen oxides in the air. However, it is not the best solution as there are better sources of energy present nowadays like solar energy.
Figure 10- Natural gas sources in India
13. Consequences of the burning of fossil fuels
ü Fossil fuels, such as coal, petroleum, and natural gas cannot be created in the laboratory as it is not possible to create the natural conditions under which they are formed. Moreover, it takes thousands of years for them to be formed.
ü Increase in air pollution- The burning of fossil fuels results in the release of unburnt carbon particles in the air. These particles act as pollutants and increase air pollution. Fossil fuels release poisonous gases such as carbon monoxide and sulphur dioxide in the atmosphere.
ü Global Warming- Fossil fuels when burnt release large amounts of carbon dioxide in the air. As the amount of carbon dioxide increases it results in an increase in the global temperature of the earth and leads to global warming.
Q. Why should we use fossil fuels economically?
Ans.- They are available in limited quantities. Burning these fuels also cause air pollution as well as global warming. Hence, we should use these fuels economically to make sure that we can use them for a longer time, the risk of global warming gets reduced, and we can live in a cleaner environment.
Q. Why fossil fuels can last for 100 years only?
Ans.- Fossil fuels are exhaustible resources which mean that they are not present in abundant quantities on the earth. They take hundreds and thousands of years to replenish. The rate at which they are being consumed today is increasing at a rapid pace. It means that more amounts of fossil fuels are being used than it is being replenished. Hence, scientists claim that they can replenish completely in 100 years.
NCERT PRACTICE QUESTIONS
1. What are the advantages of using CNG and LPG as fuels?
Ans.- The advantages of using CNG and LPG as fuels are as follows- CNG and LPG burn easily. CNG and LPG give a lot of heat energy when burnt. CNG and LPG can be transported easily through pipelines. CNG and LPG are clean fuels and they do not release smoke when burnt.
2. Name the petroleum product used for surfacing of roads.
Ans.- Bitumen is used for surfacing of roads.
3. Describe how coal is formed from dead vegetation. What is this process called?
Ans.- Dense forests got buried under the soil due to natural processes, millions of years ago. More and more soil got deposited over them and they got compressed more. This led them to get exposed to very high temperature and pressure. They slowly got converted into coal under these extreme conditions. The whole process of formation of coal from dead vegetation is known as carbonization.
4. 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 ______________ .
Ans.- (a) Coal, Petroleum, and natural gas. (b) refining. (c) Compressed Natural Gas (CNG).
5. 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)
Soln:
a) False
b) False
c) True
d) True
e) False
6. Explain why fossil fuels are exhaustible natural resources.
Ans.- The process of formation of fossil fuels requires millions of years. Dead vegetation and animals that get buried deep inside the earth require high temperature and pressure for the formation of fossil fuels, which cannot be done in the laboratory. Thus, fossils are limited. Therefore, the use of fossil fuels at a rapid rate will lead to their exhaustion.
7. Describe the characteristics and uses of coke.
Ans.- Characteristics- i) Coke is tough. ii) Coke is porous. iii) Coke is black in colour.
Uses - i) In the manufacture of steel. ii) In the extraction of metals (as a reducing agent).
8. Explain the process of the formation of petroleum.
Ans.- Dead organisms that got buried in the sea millions of years ago got covered with layers of sand and clay. Due to lack of air, high temperature and high pressure, these dead organisms got transformed into petroleum and natural gas.
9. 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.
S.No. | Year | Shortage (%) |
1. | 1993 | 7.7 |
2. | 1994 | 7.5 |
3. | 1995 | 8.2 |
4. | 1996 | 7.1 |
5. | 1997 | 7.7 |
6. | 1998 | 9.1 |
7. | 1999 | 11.2 |
Ans.-
Junior Science Topic - Coal And Petroleum. Chapter notes, video lectures, power point presentation and NCERT exercise solution. (Class 8, CBSE syllabus, chapter 05)
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