The explosion caused by pressure is a physical change, such as the explosion of steam boilers, pressure cookers, tires, balloons, thermos bottles and beer bottles.

The explosion caused by combustion is a chemical change, such as the explosion of gasoline, liquefied petroleum gas, H2, carbon monoxide, methane, gunpowder, firecrackers and flour powder.

1, physical explosion

Physical explosion is caused by physical changes (temperature, volume, pressure and other factors). Before and after the explosion, the nature and chemical composition of the explosive substance remain unchanged.

2. Chemical explosion

Chemical explosion is caused by chemical changes. The substance of chemical explosion, whether it is a mixture of combustible substance and air or explosive substance (such as explosives), is a relatively unstable system. Under the action of a certain intensity of external energy, it can produce strong exothermic reaction, high temperature, high pressure and shock wave, thus causing strong damage.

References:

Baidu encyclopedia: explosions