Gunpowder

Gunpowder, also commonly known as black powder to distinguish it from modern smokeless powder, is the earliest known chemical explosive. Gunpowder has been widely used as a propellant in firearms, artillery, rocketry, and pyrotechnics, including use as a blasting agent for explosives in quarrying, mining, and road building. It consists of a mixture of Sulfur, Carbon (in the form of Charcoal) and Potassium Nitrate (saltpeter). The sulfur and carbon act as fuels while the saltpeter is an oxidizer. If you would like to make it, First you get a bowl or something you can mix it in, Next You pour the Sulfur in, Then you put the Charcoal in, After That You Finally put the Potassium Nitrate in, Finally you mix it and there you go. Now you have Pure Gunpowder. 
Gunpowder is classified as a low explosive because of its relatively slow decomposition rate and consequently low brisance. Low explosives deflagrate (i.e., burn at subsonic speeds), whereas high explosives detonate producing a supersonic shockwave. Ignition of gunpowder packed behind a projectile generates enough pressure to force the shot from the muzzle at high speed, but usually not enough force to rupture the gun barrel. It thus makes a good propellant, but is less suitable for shattering rock or fortifications with its low-yield explosive power. Nonetheless it was widely used to fill fused artillery shells (and used in mining and civil engineering projects) until the second half of the 19th century, when the first high explosives were put into use.
Its use in weapons has declined due to smokeless powder replacing it, and it is no longer used for industrial purposes due to its relative inefficiency compared to newer alternatives such as dynamite and ammonium nitrate/fuel oil.
=== Chemistry ===
A simple, commonly cited, chemical equation for the combustion of gunpowder is:
: 2 KNO3 + S + 3 C → K2S + N2 + 3 CO2.
A balanced, but still simplified, equation is:
: 10 KNO3 + 3 S + 8 C → 2 K2CO3 + 3 K2SO4 + 6 CO2 + 5 N2.
The exact percentages of ingredients varied greatly through the medieval period as the recipes were developed by trial and error, and needed to be updated for changing military technology.
Gunpowder does not burn as a single reaction, so the byproducts are not easily predicted. One study showed that it produced (in order of descending quantities) 55.91% solid products: Potassium Carbonate, Potassium Sulfate, Potassium Sulfide, Sulfur, Potassium Nitrate, Potassium Thiocyanate, Carbon, Ammonium Carbonate and 42.98% gaseous products: Carbon Dioxide, Nitrogen, Carbon Monoxide, Hydrogen Sulfide, Hydrogen, Methane, 1.11% Water.
Gunpowder made with less-expensive and more plentiful Sodium Nitrate instead of Potassium Nitrate (in appropriate proportions) works just as well. However, it is more hygroscopic than powders made from potassium nitrate. Muzzleloaders have been known to fire after hanging on a wall for decades in a loaded state, provided they remained dry. By contrast, gunpowder made with sodium nitrate must be kept sealed to remain stable.[original research?]
Gunpowder releases 3 megajoules per kilogram and contains its own oxidant.[citation needed] This is less than TNT (4.7 megajoules per kilogram), or gasoline (47.2 megajoules per kilogram in combustion, but gasoline requires an oxidant; for instance, an optimized gasoline and O2 mixture releases 10.4 megajoules per kilogram, taking into account the mass of the oxygen).
Gunpowder also has a low energy density[how much?] compared to modern "smokeless" powders, and thus to achieve high energy loadings, large amounts are needed with heavy projectiles.
Category:Compound