Combustion about different types of candle flames

About types of flames

1. Zones of the candle Flame3
Chemistry8

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OBJECTIVES:
To analysethe factors responsible for the change in
colourof the flame.
To Define a Flame.
To differentiate the types of Flame
To distinguish the zones of the Candle Flame

3. PEREQUISITE:
1.What is combustion?
2.Substance that produce heat and Light energy during Combustion is
called
3.Give the conditions necessary for Combustion?

4. Why do we observe different coloursin the Flame?
•A FlAMEis a region where combustion of a Fuel takes place.
•The colourof the flame depends on the following Factors

5. The colourof the flame depends on the
following Factors :
•Temperature
•Amount of Oxygen
•Nature of the substance Burning

6. Types of Flame:
1.Luminous Flame:
•Yellow Flame is called Luminous
flame as it emits lot of Yellow Light.
•A luminous flame is generally
observed when there is insufficient
Oxygen supply (incomplete combustion).
•Temperature is Low.
•Leaves behind residue

7. Types of Flame:
2.Non-Luminous Flame:
•A blue flame is also called a non-luminous flame
as it emits very little light.
•A blue flame is generally observed when there is
adequate amount of oxygen available
(i.e., complete combustion).
•Blue flame leaves behind no residue.

8. .
LuminousFlame Non-Luminous Flame
Bright Yellow in colour Blue in colour
Producesmore Light Produces less light
Produces more soot or residueProduces less soot or residue
Temperature is less Temperature is more

9. Zones of the Candle Flame
•A candle flame can be divided into three
zones, depending on the amount of
Oxygen available.
1.The outer zone (blue)
2.The middle zone (yellow)
3.The inner zone (black)

10. Zones of the Candle Flame:

11. Zones of the candle Flame:
•The outer zone (blue) is the hottest part of the flame. In this zone, the wax vapours
have enough oxygen to burn completely (producing carbon dioxide and water).
This zone emits very little light.

12. Middle zone of the candle Flame:
•The middle zone (yellow) is less
hot than the outer zone. Here,
incomplete combustion of wax
vapours(due to low oxygen) produces
carbon particles (which glow, giving the
zone its yellow colour) and carbon
monoxide.
This zone emits the most light.

13. Inner Zone of the candle Flame:
•The inner zone (black) is the coolest
part of the flame. In this zone, the wax
vapoursremain unburned as no oxygen
is available. This zone is completely
Dark and emits no light.

15. Assignment questions:
1. What are the 3 zones of candle Flame.
2. Which zone of the candle Flame is the hottest?
3.What are the zones of candle flame, and explain in detail with
diagram.

16. 4.Here are three different zones of candle flame A, B and C as shown in figure. Which
one of the following is correct?
1.B is the hottest part of flame
2.C is moderately hot
3.A is the hottest part of flame
4.A is moderately hot whereas C is the coldest part

17. 5. During the burning of a candle, different zones of combustion in the flame are
listed below:
A. Outermost zone
B. Innermost zone
C. Middle zone
The correct order of temperature of zones is :
A). A>B>C
B). C>B>A
C). B>C>A
D). A>C>B

18. Home assignment:
1.What is Luminous Flame?
2.Differentiate Luminous flame from non-Luminous flame?
3.Define complete combustion?
4.Define incomplete combustion?