A CHEMICAL PROCESS IN WHICH A SUBSTANCE REACTS WITH THE OXYGEN OF AIR TO GIVE HEAT & LIGHT IS CALLED COMBUSTION.

• SPOTANOEUS COMBUSTION

• RAPID COMBUSTION

• COMPLETE COMBUSTION

• INCOMPLETE COMBUSTION

• EXPLOTION

RAPID COMBUSTION

• Combustion in which a substance burns rapidly and produces heat and flame is known as rapid combustion, such as combustion of natural gas, LPG, petrol etc.• This is usually attained by introducing external heat. • Substances which undergo rapid combustion have lower ignition temperature

• When a substance suddenly starts burning into a flame; without the supply of any external cause such as heating; the combustion is called spontaneous combustion.• Substances; which have relatively low temperature of ignition generally burn by spontaneous combustion.

• A reaction or process which entails only partial burning of a fuel. • This may be due to a lack of oxygen or low temperature, preventing the complete chemical reaction.

• A reaction or process which entails only partial burning of a fuel. • This may be due to a lack of oxygen or low temperature, preventing the complete chemical reaction.• Carbon monoxide is produced as a by product from incomplete combustion

• When combustion is accompanied by sudden production of heat, sound and large amount of gas, it is called explosion.• Firecrackers and bombs are substances which show explosion

• Phosphorous and sulphur start burning instantaneously; at room temperature.• Haystacks, linseed oil, coal, pyrite, etc. sometimes start burning suddenly with flame because of increase in temperature.• In coal mines, fire breaks out many a times because of combustion of coal dust.• Fire often breaks out suddenly because of increase in temperature due to sun or friction.

•COMBUSTIBLE •NON COMBUSTIBLE SUBSTANCES

• SUBSTANCES WHICH CAN BURN ARE CALLED AS COMBUSTIBLE SUBSTANCES.

COAL

WOOD LOG

WATER

BRICK

• SUBSTANCES WHICH DO NOT BURN ARE CALLED NONCOMBUSTIBLE SUBSTANCES.

CONDITIONS NECESSARY FOR COMBUSTION

CONDITIONS NECESSARY FOR COMBUSTION

• PRESENCE OF THE COMBUSTIBLE SUBSTANCES ( A SUBSTANCE WHICH CAN BURN) • PRESENCE OF A SUPPORTER OF OXYGEN ( I.E. AIR) • HEATING THE COMBUSTIBLE SUBSTANCES TO ITS IGNITION TEMPERATURE.