Free Chemistry Dictionary

Video Example : Ignition



Definition of Ignition

Ignition may be defined as Fire lighting, the human act of creating a fire for warmth, cooking

More About Ignition

  • Ignition is a form of Combustion, exothermic chemical reactions between a fuel and an oxidant accompanied by the production of heat and conversion of chemical species
  • Ignition also refers to Minimum ignition energy, the minimum amount of energy required to ignite a combustible vapor, gas or dust cloud
  • Another term associated with ignition is “Ignition temperature”
  • The minimum temperature at which a substance catches fire is called “ignition temperature”
  • Different substances catch fire at different temperatures
  • During extreme heat of summer, at some places dry gases catch fire. From grasses this fire spreads to trees and is very soon the entire forest is on fire. It is very difficult to control such fires
  • A mixture of antimony trisulphide, potassium chlorate and white phosphorous with some glue and starch is applied on the head of a match stick made of suitable wood
  • When struck against a rough surface, white phosphorous gets ignited due to friction
  • This started the combustion of match
  • A combustible substance cannot catch fire as long as its temperature is lower than ignition temperature
  • Cooking oil catches fire if a frying pan is kept for long on a stove
  • Kerosene oil and wood do not catch fire on their own at room temperature. But if kerosene oil is heated a little, it will catch fire
  • If wood is heated a little, it does not catch fire
  • This is because ignition temperature of kerosene oil is lower than that of wood
  • It is essential for a substance to reach ignition temperature to burn
  • When a little water is taken in a paper cup and heated, water will begin to boil but the paper cup will not burn
  • This is because heat is transferred to water from the paper cup by conduction
  • In the presence of water, ignition temperature of paper cup is not reached. Hence, it does not burn
  • When an empty paper cup is heated, it burns
  • The substances which have very low ignition temperatures are called “inflammable substances”

Question: ---

What is the ignition temperature of natural gas?

The ignition temperature of natural gas assuming perfect combustion conditions like absolute combustion under adiabatic conditions is 2,000 °C. The first law of thermodynamics is used as a basis on which the temperature is determined and takes into account that the heat of combustion is entirely used for heating the fuel.