Introduction :
Chemical reactions that releases energy are known as exothermic reactions.
Case I: When the reaction proceeds slowly, released energy will be dissipated smoothly and there will be few noticeable effects other than an increase in temperature.
Case II: On the other hand, when the reaction proceeds very rapidly, the energy will not be dissipated smoothly. A huge amount of energy can be deposited into a relatively small volume of atmosphere, then manifest itself by a rapid expansion of hot gases, which in turn can create a shock wave or propel fragments outwards at high speed.
There are three primary fields of application for these chemcial explosions: propellants, explosives and pyrotechnics.
Propellants works when they create a high gas pressure for moving projectiles or rockets and for similar uses.
Explosives works when they create a disruption of solid or liquid bodies, as in construction, mining or warfare.
Pyrotechnics works when they have effects that are mainly sound and light, but include many other varied applications, mainly on a small scale.
Fireworks are used as an application for entertainment, a show of light, noise and motion.
Smokeless Powder: Vielle
discovered how to make a propellant from cellulose nitrate in 1886. The
work was started with low-nitrogen guncotton, or pyrocotton, with
11%-12% of nitrogen, and plasticized it with ether and alcohol.
Pyrocotton will dissolve completely in this solvent. This gel was rolled
out into sheets and then the sheets were broken up into powder, after
this the powder formed into grains, and these grains, mixed with various
additives to control the rate of burning, chemical properties and
stability in storage, made a propellant called smokeless powder that
could replace gunpowder, and was more powerful.
Aromatic Explosives: One of the first aromatic explosives was picric acid, or trinitrophenol, C6H2(NO2)3OH. This particular explosive was first prepared in 1771 by Woulfe as a dye, and was also used in medicine, long before it was first employed as an explosive in 1830. Name was so given because of it's extremely sharp or bitter taste, and also in Greek word it means pikros, "sharp." It forms pale yellow crystals of density 1.76 g/cc, melting at 122°C and exploding above 300°C. It is too sensitive to heat to be poured into shells, and must be press-loaded, meanwhile another effect of it is corrosion of metals, forming sensitive picrates. The most famous aromatic explosive is trinitrotoluene, called TNT for short. TNT is deficient in oxygen, so makes a cloud of black smoke. It is a popular bursting charge for shells and bombs, replacing picric acid after World War I.
Chemical reactions that releases energy are known as exothermic reactions.
Case I: When the reaction proceeds slowly, released energy will be dissipated smoothly and there will be few noticeable effects other than an increase in temperature.
Case II: On the other hand, when the reaction proceeds very rapidly, the energy will not be dissipated smoothly. A huge amount of energy can be deposited into a relatively small volume of atmosphere, then manifest itself by a rapid expansion of hot gases, which in turn can create a shock wave or propel fragments outwards at high speed.
There are three primary fields of application for these chemcial explosions: propellants, explosives and pyrotechnics.
Propellants works when they create a high gas pressure for moving projectiles or rockets and for similar uses.
Explosives works when they create a disruption of solid or liquid bodies, as in construction, mining or warfare.
Pyrotechnics works when they have effects that are mainly sound and light, but include many other varied applications, mainly on a small scale.
Fireworks are used as an application for entertainment, a show of light, noise and motion.
Some more examples:
Black Powder: Black powder was invented as a pyrotechnic substance, then it was applied as a propellant in firearms, and finally used in engineering and mining. The history of black powder and firearms relates to Cannon.Aromatic Explosives: One of the first aromatic explosives was picric acid, or trinitrophenol, C6H2(NO2)3OH. This particular explosive was first prepared in 1771 by Woulfe as a dye, and was also used in medicine, long before it was first employed as an explosive in 1830. Name was so given because of it's extremely sharp or bitter taste, and also in Greek word it means pikros, "sharp." It forms pale yellow crystals of density 1.76 g/cc, melting at 122°C and exploding above 300°C. It is too sensitive to heat to be poured into shells, and must be press-loaded, meanwhile another effect of it is corrosion of metals, forming sensitive picrates. The most famous aromatic explosive is trinitrotoluene, called TNT for short. TNT is deficient in oxygen, so makes a cloud of black smoke. It is a popular bursting charge for shells and bombs, replacing picric acid after World War I.
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