Combustion & Flame
⭕ Combustion:
Combustion is a chemical reaction in which a substance combines with
oxygen and releases energy in the form of heat and light.
Substance + O2 Light + Heat
Example:
Combustion of Wood: When wood undergoes combustion, it produces
carbon dioxide, water vapour, light, and heat.
Wood + O2 CO2 + H2O + Light + Heat
→ Conditions of Combustion:
1. Presence of a Combustible Substance
2. Supply of Oxygen (or Air)
3. Ignition Temperature (Minimum Temperature to Start Burning)
o Ignition Temperature:
Ignition temperature is the lowest temperature at which a
combustible substance starts burning.
→ Types of Substances:
1. Combustible Substance:
These substances burn in air and produce heat and light.
Examples: Wood, paper, petrol, LPG, kerosene, coal.
2. Non-combustible Substances:
These substances do not burn in air.
Examples: Glass, metals (like iron), sand, stone, water.
3. Inflammable (Highly Combustible) Substances:
These substances catch fire very easily and have low ignition
temperature.
Examples: Petrol, alcohol, LPG, acetone.
SANKALP CLASSES ‖ ASHWANI KUMAR 1
, 🔬 Experiment
→ To Show Oxygen is Needed for Combustion:
Material Requires:
o A small candle
o A glass jar or transparent jar
o A matchbox or lighter
o A plate
Steps:
1. Place the candle upright on a plate.
2. Light the candle with a matchstick.
3. Now cover the burning candle with the glass jar carefully.
4. Watch what happens.
Observation:
The flame foes out after a few second.
Conclusion:
(i) The candle stops burning because the oxygen inside the glass gets
used up.
(ii) This proves that oxygen is essential for combustion.
SANKALP CLASSES ‖ ASHWANI KUMAR 2
⭕ Combustion:
Combustion is a chemical reaction in which a substance combines with
oxygen and releases energy in the form of heat and light.
Substance + O2 Light + Heat
Example:
Combustion of Wood: When wood undergoes combustion, it produces
carbon dioxide, water vapour, light, and heat.
Wood + O2 CO2 + H2O + Light + Heat
→ Conditions of Combustion:
1. Presence of a Combustible Substance
2. Supply of Oxygen (or Air)
3. Ignition Temperature (Minimum Temperature to Start Burning)
o Ignition Temperature:
Ignition temperature is the lowest temperature at which a
combustible substance starts burning.
→ Types of Substances:
1. Combustible Substance:
These substances burn in air and produce heat and light.
Examples: Wood, paper, petrol, LPG, kerosene, coal.
2. Non-combustible Substances:
These substances do not burn in air.
Examples: Glass, metals (like iron), sand, stone, water.
3. Inflammable (Highly Combustible) Substances:
These substances catch fire very easily and have low ignition
temperature.
Examples: Petrol, alcohol, LPG, acetone.
SANKALP CLASSES ‖ ASHWANI KUMAR 1
, 🔬 Experiment
→ To Show Oxygen is Needed for Combustion:
Material Requires:
o A small candle
o A glass jar or transparent jar
o A matchbox or lighter
o A plate
Steps:
1. Place the candle upright on a plate.
2. Light the candle with a matchstick.
3. Now cover the burning candle with the glass jar carefully.
4. Watch what happens.
Observation:
The flame foes out after a few second.
Conclusion:
(i) The candle stops burning because the oxygen inside the glass gets
used up.
(ii) This proves that oxygen is essential for combustion.
SANKALP CLASSES ‖ ASHWANI KUMAR 2
