- Combustion: The process of burning a substance in the presence of air (oxygen) and undergoes a chemical reaction to produce heat and light.
- The substances which burn in air are called combustible.
- Oxygen (in air) is essential for combustion.
- During the process of combustion, heat and light are given out.
- Ignition temperature is the lowest temperature at which a combustible substance catches fire.
- Types of combustion: The type of combustion differs depending on the type of fuel. Based on nature and intensity combustions are classified into three types. They are:
(i) Rapid combustion
(ii) Spontaneous combustion
(iii) Explosion
- Flame: It is a zone or burning vapour. The substances which vaporise during burning give flames. Example: Kerosene oil and molten wax.
- Inflammable substances have very low ignition temperature.
- Fire can be controlled by removing one or more requirements essential for producing fire.
- Water is commonly used to control fires.
- Water cannot be used to control fires involving electrical equipments or oils.
- There are three different zones of a flame – dark zone, luminous zone and non-luminous zone.
- Fuel is any material that is burned to obtain energy that can be used to heat or move another object.
- A good fuel must:
• Be readily available.
• Be cheap.
• Burn easily at a moderate rate.
• Produce a large amount of heat.
• Not leave behind any undesirable substances.
- Fuels differ in their efficiency and cost.
- Fuel efficiency is expressed in terms of its calorific value which is expressed in units of kilo joule per kg.
- Types of Fuels:
(i) Solid Fuels: Combustible substances which are solid at room temperature. Example: coal, coke, wood, charcoal, etc.
(ii) Liquid fuels: Volatile liquids which produce combustible vapour. Example: Petrol, kerosene, alcohol, diesel, etc.
(iii) Gaseous fuels: Combustible gases or mixture of combustible gases. Example: Natural gas, LPG, biogas, coal gas, etc.
- Effects of Burning of Fuels:
(i) Carbon fuels like wood, coal petroleum release un burnt carbon particles. These are dangerous pollutants causing respiratory diseases, such as asthma.
(ii) Incomplete combustion of carbon fuels gives carbon monoxide which is a poisonous gas.
(iii) Increased concentration of carbon dioxide in the air is believed to cause global warming.
(iv) Oxides of Sulphur and nitrogen dissolve in rain water and form acids. Such rain is called acid rain. It is very harmful for crops, buildings and soil.
- Un burnt carbon particles in air are dangerous pollutants causing respiratory problems.
- Incomplete combustion of a fuel gives poisonous carbon monoxide gas.
- Increased percentage of carbon dioxide in air has been linked to global warming.
- Oxides of sulphur and nitrogen produced by the burning of coal, diesel and petrol cause
- Acid rain which is harmful for crops, buildings and soil.
For More :-
CBSE
Class–VII | CHAPTER – 1 Integers | NMMS
Revision Notes à Click Here
Tracing
Changes Through a Thousand Years | NMMS Revision Notes | Class 7 | Social à Click Here
New
Kings and Kingdoms | NMMS Revision Notes | Class 7 | Social à Click Here
The
Delhi Sultanate | NMMS Revision Notes | Class 7 Social à Click Here
The
Mughal Empire | NMMS Revision Notes | Class 7 Social à Click Here
Tribes
Nomads and Settled Communities | NMMS Revision Notes | Class 7 Social à Click Here
Devotional
Paths to the Divine | NMMS Revision Notes | Class 7 Social à Click Here
The
Making of Regional Cultures | NMMS Revision Notes | Class 7 Social à Click Here
Eighteenth
Century Political Formations | NMMS Revision Notes | Class 7 Social à Click Here
Environment
| NMMS Revision Notes | Class 7 Social à Click Here
Inside
Our Earth | NMMS Revision Notes | Class 7 Social à Click Here
Our
Changing Earth | NMMS Revision Notes | Class 7 Social à Click Here
Air |
NMMS Revision Notes | Class 7 Social à Click Here
Water
| NMMS Revision Notes | Class 7 Social à Click Here
Human
Environment Interactions the Tropical | NMMS Revison Notes | Class 7 Social à Click Here
Life
in the Deserts | NMMS Revision Notes | Class 7 Social à Click Here
On
Equality | NMMS Revision Notes | Class 7 Social à Click Here
How
the State Government Works | NMMS Revision Notes | Class 7 Social à Click Here
Role
of the Government in Health | NMMS Revision Notes | Class 7 Social à Click Here
Growing
up as Boys and Girls | NMMS Revision Notes | Class 7 Social à Click Here
Women
Change the World | NMMS Revision Notes | Class 7 Social à Click Here
Understanding
Media | NMMS Revision Notes | Class 7 Social à Click Here
Markets
Around Us | NMMS Revision Notes | Class 7 Social à Click Here
A
Shirt in the Market | NMMS Revision Notes | Class 7 Social à Click Here
Nutrition
in Plants | NMMS Revision Notes | Class 7 Science à Click Here
Nutrition
in Animals | NMMS Revision Notes | Class 7 Science à Click Here
Heat |
NMMS Revision Notes | Class 7 Science à Click Here
Acids
Bases And Salts | NMMS Revision Notes | Class 7 Science à Click Here
Physical
And Chemical Changes | NMMS Revision Notes | Class 7 Science à Click Here
Respiration
In Organisms | NMMS Revision Notes | Class 7 Science à Click Here
Transportation
in Animals and Plants | NMMS Revision Notes | Class 7 Science à Click Here
Force
and Pressure | NMMS Quick Revision Notes
| Class: 8 Physics à
Click Here
Reproduction
In Plants | NMMS Revision Notes | Class 7 Science à Click Here
Motion
And Time | NMMS Revision Notes | Class 7 Science à Click Here
Electric
Current and its Effects | NMMS Revision Notes | Class 7 Science à Click Here
Light
| NMMS Revision Notes | Class 7 Science à Click Here
Waste
Water Story | NMMS Revision Notes | Class 7 Science à Click Here
How
When and Where | NMMS Revision Notes | Class 8 Social à Click Here
From
Trade to Territory | NMMS Revision Notes | Class 8 Social à Click Here
Ruling
the Countryside | NMMS Revision Notes | Class 8 Social à Click Here
Tribals
Dikus and Vision of Golden Age | NMMS Revision Notes | Class 8 Social à Click Here
When
People Rebel | NMMS Revision Notes | Class 8 Social à Click Here
Weavers
Iron Smelters and Factory Owners | NMMS Revision Notes | Class 8 Social à Click Here
Civilising
the Native Educating the Nation | NMMS Revision Notes | Class 8 Social à Click Here
Women
Caste and Reform | NMMS Revision Notes | Class 8 Social à Click Here