Combustion & Flame. By Vishnu M Nair. Index. Basic needs How to extinguish Fire The Ignition temperature Inflammable combustion Rapid & Spontaneous Combustion Zones Of Candle Flame Explosion Fuel Fuel Efficiency Global Warming Acid Rain. Basic Needs.
Combustion & Flame
Vishnu M Nair
How to extinguish Fire
The Ignition temperature
Rapid & Spontaneous Combustion
Zones Of Candle Flame
The major conditions for a fire to burn is
Combustion – A chemical process in which a substance reacts with oxygen to give off heat is called combustion.
We now understand that fire be seen with the help of the above
Q1. What will you do if you see a uncontrolled fire?
The answer to that question is so simple.
Fire can only burn with presence of oxygen and fuel and if temperature is above flash point.
So to extinguish fire remove away any of these
Example: If fire is on a human body we should cover him tightly with a blanket like that on the picture below
2. By taking away the fuel
3. By decreasing the temperature below flash point
This can be done by poring water over the fire
Q. What will you do if the fire is caused by an electric short circuit
In such a case DO NOT TRY TO EXTINGUISH IT WITH WATER.
As water may come in contact with electric shock which could lead to serious injuries or even DEATH
The lowest temperature at which a substance catches fire is called its Ignition Temperature
It is essential for a substance to reach its ignition temperature to burn
The Substances which have very low ignition temperature and can easily catch fire with a flame are called inflammable substances
Some examples are: Petrol, Alcohol, Liquid Petroleum Gas
Rapid Combustion: Gas burns rapidly and produces heat and light. Such combustion is known as rapid combustion.
Spontaneous Combustion: The type of combustion in which a material suddenly bursts into flames, without the application of any apparent cause is called Spontaneous Combustion
Zones of Candle Flame
When a cracker is ignited, a sudden reaction takes place with the evolution of heat, light and sound. A large amount of gas formed in the reaction is liberated. Such a reaction is called explosion.
The substance that undergoes combustion is said to be combustible or FUEL
A Good Fuel – A good fuel is:-
The amount of heat produced on complete combustion of 1 kg fuel is called its calorific value. The calorific value is expressed in a unit called kilojoules per kg (kj/kg).
Combustion of most fuels releases carbon dioxide in environment. Increased carbon dioxide in air is believed to cause global warming
Burning of coal and diesels releases sulphur dioxide gas. Oxides of sulphur and nitrogen dissolve in rain water and forms acids.
Such a rain is called acid rain.
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