____ can be used as a fuel
Answers
Answer:
Coal can be used as a fuel
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Answer:
Introduction
We use various materials for our basic needs. Some of them are found in nature and some have been made by human efforts.
Natural resources
Definition
The sources which are obtained from nature are called natural resources.
Types of natural resources
1. Inexhaustible natural resources
These sources are present in unlimited quantity in nature and are not likely to be exhausted by human activities.
Examples: Sunlight, air, etc.
2. Exhaustible natural resources
The amount of these resources in nature is limited, they can be exhausted by human activities.
Examples: Forests, coal, petroleum. minerals, wild life, natural gas, etc.
Booster 1
Can sunlight get exhausted by human activities?
Explanation
Sunlight is an ultimate source of energy available free of cost. It cannot be exhausted by human activities as it is produced by a natural process of fusion inside the sun. Due to this nuclear fusion extremely large amount of energy is produced which comes in the form of sunlight.
Test Yourself
1. Name some inexhaustible substances other than sunlight and air.
2. Which fuel is used for running vehicles?
(a) Wood(b) Coal (c) Diesel(d) Charcoal
3. Which of the following is a natural resource?
(a) Tea(b) Cooked food (c) Air(d) Toffee
4. inexhaustible natural resource in nature are
(a) limited(b) unlimited (c) scarce(d) not present
5. Which of the following is an exhaustible natural resource?
(a) Air(b) Water (c) Soil(d) Forest
Types of natural resources
Memory map
Fuels
A fuel is a substance, which bums In air to produce energy without releasing harmful gases in large quantities.
Fuels can be classified as natural (primary) fuels and derived (secondary) fuels. If a fuel Is present in its natural state, it is called natural fuel. If a fuel is processed to improve its quality, it Is called derived fuel.
Memory map
Calorific value of a fuel
Calorific value of a fuel is the amount of heat liberated by complete burning of a unit mass or volume of a fuel. For liquid or gaseous fuels, volume of fuel is considered while for solid fuels mass of fuel is considered to find out the calorific value.
Characteristics of an ideal fuel
(1) It should have a high calorific value.
(2) It should not cause any pollution or should not produce harmful gases on combustion.
(3) It should be of low cost and easily available.
(4) It should be easy to handle, store and transport.
(5) It should have moderate ignition temperature.
(6) It should have moderate rate of combustion.
Fossil fuels
Exhaustible natural resources like coal, petroleum and natural gas were formed from the dead remains of living organism (fossils). So, these are called fossil fuels. Coal and petroleum are very important natural resources and play a vital role in modem society. They are found in the earth's crust.
Coal
Coal is a complex mixture of carbon, hydrogen and oxygen compounds. me nitrogen, sulphur and phosphorus compounds are also present in it. It is found in coal mines deep under the surface of earth. Story of formation : It is believed that millions of years ago, the ground below the forests was split open by natural forces such as earthquakes and volcanoes. The forests got buried under the surface of earth. Thus, the plants had no contact with oxygen. Successive layers of sediments sealed the buried plants. Over millions of year, these deposits were subjected to tremendous pressure and heat finally transformed them into coal.
Carbonisation: The chemical process involved in the transformation of punt matter into coal is called the carbonisation of plant matter.
The carbon content of coal depends upon the variety of the coal. The higher the temperature and pressure of the Earth and the longer the coal has been hurried under the Earth, the more is the carbon content in it. So, the different varieties of coal are as follows (1) Peat (2) Lignite (3) Bituminous coal (4) Anthracite coal
Peat: It is the youngest variety of coal which is light brown in colour. It contains minimum carbon content and produces less heat and more smoke on burning. Its calorific value is 10 to 15 kJ/g.
Lignite: It is known as soft coal. It is also brown in colour and contains more carbon than peat. Its calorific value is 15 to 20 kJ/g.
Bituminous coal: It is the common household coal. It is the most abundant f and Is compact, black, contains more carbon and produces more heat than peat and lignite. Its calorific value is 30 to 35 kJ/g.
Anthracite coal: It is the hardest coal containing maximum carbon. T+ burns with difficulty due to presence of very low volatile matter. Therefore it is not used for household purposes, it is mainly used for industrial purposes. Its calorific value is 28 to 30 kJ/g.