In creating an explosion, three conditions are combustible gas, adequate oxygen, and sufficient heat. What is the fourth condition?

The fourth condition for creating an explosion, in addition to combustible gas, adequate oxygen, and sufficient heat, is the proper mixing of gas and oxygen. This is crucial because for combustion to occur, the fuel (combustible gas) must be mixed with the oxidizer (oxygen) in the right proportions. If the mixture is too rich in fuel or too lean (not enough fuel), combustion may not occur effectively, and an explosion is unlikely. The proper ratio ensures that there is enough oxygen available to react with the gas, leading to a rapid release of energy and an explosion.

While factors such as high pressure, specific temperature, and catalysts can influence the combustion process and the characteristics of an explosion, they are not universally required for all explosions. Proper mixing, however, is essential to ensure the necessary chemical reaction occurs efficiently.