This document discusses combustion and flames. It defines combustion as a chemical process where a substance reacts with oxygen to produce heat and light. It was discovered by Antoine Lavoisier. There are three main types of combustion: rapid, spontaneous, and slow. Rapid combustion occurs in fires and continues as long as fuel is available. Spontaneous combustion occurs when substances ignite without an external heat source. Slow combustion is the gradual reaction with oxygen over a long period of time without light produced. The parts of a flame are the outer, middle, and inner zones, which differ in temperature and the type of combustion occurring. The color of flames is caused by the excitation of electrons to higher energy levels during combustion, with larger atoms emitting

1. COMBUSTION
AND
FLAME

2. By the end of this seminar you will be
able to :-
 Tell the definition of combustion and
the scientist who discovered it.
 The types of combustion .
 Parts of the flame
 And finally what causes the colour of
the flame

3. COMBUSTION
A chemical process in
which a substance reacts
with oxygen to give off
heat and light is
called combustion

4. Antoine laurent
lavoisier discovered
the combustion
process

5. Types of combustion

6. Rapid combustion
 Rapid combustion is a form of combustion in which large
amounts of heat and light energy are released.
 This often occurs as a fire
 Rapid combustion continues as long as fuel is available

7. EXAMPLES OF
RAPID
COMBUSTION
Burning in lpg

8. Spontaneous combustion
 Spontaneous combustion
occurs when a
substance burns on its
own without the external
application of heat .

9. Examples of spontaneous combustion
White phosphorus
burns spontaneously
in air at room
temperature
without external
heat being supplied
to it .

10. Explosion
 An explosion occurs when the chemical
reactions of combustion take place with the
release of heat , light , sound and large
amount of gas .

11. Fire works
Examples of explosion
Dynamite
explosion

12. Slow combustion
The gradual combination of a substance
with oxygen over a long period of time is
called slow combustion.
It is a slow process.
There is no light produced and heat is
produced at a rate so slow that we cannot
feel it

13. EXAMPLES OF SLOW COMBUSTION
RUSTING OF IRON
CELLULAR RESPIRATION

14. Parts of the
flame

15. Outer most
zone
The outer most zone is non luminous , it is bluish
in colour and is the hottest region of the flame .
This is a zone of com plete combustion where
hydrocarbons in the wax vapours burns
completely , forming carbon dioxide and water .
No soot is produced and hence this zone emits
very little light

16. Middle
zone
The middle zone is luminous , yellowish in colour ,
and is not as hot as the outer zone . This is a zone
of incompletecombustion where wax vapours ,
due to low oxygen supply , are burnt
incompletely . The unburnt carbon particles
produced glow brightly , give this zone its yellow
colour and make it emit most light.

17. Inner
zone
The inner zone around the wick is dark and is the
coolest part of the flame . No combustion takes
place here as no oxygen is available to burn the
wax vapours . As there is no combustion , no light
is produced in this zone

18. What causes the
different colours
of flame?

19. • The colors observed during
the flame test result from the
excitement of the
electrons caused by the increased
temperature. The electrons "jump"
from their ground state to a higher
energy level. ... The color emitted
by larger atoms is lower in energy
than the light emitted by smaller
atoms.