Chapter 6 Combustion and Flame

  • When a substance is burnt in the presence of oxygen than it gives off heat, process is called combustion and that substance is called combustible.
  • For the combustion reaction presence of oxygen (air) is must.
  • Heat and light are also produced with carbon dioxide during the process of combustion.
  • The lowest temperature at which a substance catches fire easily known as ignition temperature.
  • Inflammable substances generally have very low ignition temperature.
  • To extinguish fire generally, water is used.
  • If the fire involving electrical equipments or oils then water cannot be used to extinguish it.
  • Combustion is of various types: Rapid combustion, spontaneous combustion or explosion.
  • The substance which vaporize during the burning process gives flame.
  • Flame have different zones like: dark zone, luminous and non- luminous zone.
  • An ideal fuel have high calorific value and readily available. It is also easy to transport.
  • A calorific value shows the efficiency of the fuel.
  • Carbon monoxide is produced during incomplete combustion of fuel which is a poisonous gas.
  • As the increasing temperature of the earth with increase in the amount of carbon dioxide leads to the global warming.
  • When the oxides of nitrogen and Sulphur mix with the rain water, it forms the acid and then this type of rain is known as acid rain.
  • Calorific value may be defined as the heat energy produced on complete combustion of 1 kg of fuel.
  • On large scale, cutting down the trees, known as deforestation.
  • The reaction that takes place in sudden with the evolution of heat, light and a large amount of gas is known as explosion.
  • The region where combustion of gaseous substances take place is known as flame.

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Exercise 1 ( Page No. : 75 )

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