Descriptive

EXPLOSIVE   MATERIAL    
An explosive material, also called an explosive, is a reactive substance that contains a great amount of potential energy that can produce an explosion if released suddenly, usually accompanied by the production of light, heat, sound, and pressure. An explosive charge is a measured quantity of explosive material.
This potential energy stored in an explosive material may be
• chemical energy, such as nitroglycerine or grain dust
• pressurized compressed gas, such as a gas cylinder or aerosol can
• nuclear, such as fissile isotopes of uranium-235 and plutonium-239
Explosive materials may be categorized by the speed at which they expand. Materials that detonate (explode faster than the speed of sound) are said to be high explosives and materials that deflagrate are said to be low explosives. Explosives may also be categorized by their sensitivity. Sensitive materials that can be initiated by a relatively small amount of heat or pressure are primary explosives and materials that are relatively insensitive are secondary explosives.
[edit] Type of reaction
[edit] Chemical
An explosion is a type of spontaneous chemical reaction (once initiated) that is driven by both a large exothermic change (great release of heat) and a large positive entropy change (great quantities of gases are released) in going from reactants to products, thereby constituting a very thermodynamically favorable process in addition to one that propagates very rapidly. Thus, explosives are substances that contain a large amount of energy stored in chemical bonds. The energetic stability of the gaseous products and, hence, their generation comes from the formation of strongly bonded species like carbon monoxide, carbon dioxide, and (di)nitrogen, which contain strong double and triple bonds having bond strengths of nearly 1,000 kJ/mole. Consequently, most commercial explosives are organic compounds containing -NO2, -ONO2 and -NHNO2 groups that when detonated release...