# Black powder

## The invention

Black powder apparently was invented in China in the thirteenth century in the Tang Dynasty

Tang Emperor

Anyway, here is the first recipe, which dates from a century later:

## Production

For the production, you must have: - Charcoal powder ($C$) - Saltpetre, potassium nitrate ($KNO_3$) - Powdered sulfur ($S_8$)

## The réaction

The oxidation reaction of sulfur and carbon produces very quickly the two gases $CO_2$ and $N_2$ and releases intense heat: $10KNO_3$ $+$ $8C$ $+$ $\frac{3}{8}S_8$ $\rightarrow 2K_2CO_3$ $+$ $3K_2SO_4$ $+$ $5N_2$ $+$ $6CO2$ It is a redox reaction where (click !) - The nitrogen atom goes from E.O. ......... to ......... - The carbon atom goes from E.O. ......... to ......... - The sulfur atom goes from E.O. ......... to .........

## The use

Black powder is used - in firearms. It is said that the first gun was used in the famous battle of Crécy (1346), but nothing is less certain. In any case, John the Blind (John of Luxembourg) was pierced by an arrow:

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in blasts (quarries, roads, tunnels, ..)

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in fireworks.

According to the desired effect, salts of various elements must be added: