CBSE Class 08 Science
Study Points
Chapter 6: Combustion and Flame
⑴ Combustion: The process of burning a substance in the presence of air (oxygen) and undergoes a chemical reaction to produce heat and light.
⑵ The substances which burn in the air are called combustible.
⑶ Oxygen (in air) is essential for combustion.
⑷ During the process of combustion, heat and light are given out.
⑸ Ignition temperature is the lowest temperature at which a combustible substance catches fire.
⑹ Types of combustion: The type of combustion differs depending on the type of fuel. Based on nature and intensity, combustions are classified into three types. They are:
(i) Rapid combustion
(ii) Spontaneous combustion
(iii) Explosion
⑺ The calorific value of a fuel is expressed in kilojoules per kilogram (kJ/kg).