4. 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
5. • 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.
6. • 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.
7.
8. • 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
9.
10. • 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
11. • 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.
19. 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.
