Combustion and Flame Test - 5

L.P.G. is a mixture of hydrocarbons. It consists of butane, propane and ethane but butane and propane are the two major constituents of L.P.G.

Calorific value of a substance is the amount of heat released during the combustion of a specified amount of fuel or food. The calorific value is the characteristic of a substance.

 Natural gas has the highest calorific value of 50000 kJ/kg Petrol has 45000 kJ/kg Kerosene has 45000 kJ/kg and Coke has 28000 kJ/kg

All the given substances can act as fuels but butane is considered as a good fuel because of the following characteristics: (i) Exists in gaseous state (ii) Has high calorific value (iii) Does not form poisonous products during combustion

The process of a substance burning in the presence of air with evolution of heat is called combustion.

Fuels and hydrocarbons burn in oxygen and form CO₂ + 2O₂ → CO₂ + 2H₂O + heatand give out heat. CH₄ + 2O₂ → CO₂ + 2H₂O + heat

Combustion is an oxidation reaction accompanied by heat and light

Diamond is a non-combustible substance.

The temperature at which a substance starts burning on heating is called ignition temperature. Highly    inflammable substances have a low ignition temperature. Hence, they catch fire easily.

A burning substance will be extinguished if the temperature falls below its ignition temperature.