Carbide Cannons & Miners’ Lamps – The Chemistry?

Chemistry, Technology
When I was a kid, a friend showed me what he called an acetylene cannon. Many know it as a carbide cannon. What made it work? It's all a matter of chemistry. Which Carbide? A carbide is a compound in which carbon is bonded to a more electropositive element. Silicon carbide (SiC) and tungsten carbide (WC) are two well-known examples. What carbide do carbide cannons use? Calcium Carbide The answer is calcium carbide. Lime and coke are placed in an electric furnace. The chemical reaction is: CaO + 3 C → CaC2 + CO2↑ What makes calcium oxide so interesting is its bonding. The valence of calcium is +2. Ordinarily, carbon is assigned a valence of 4. Something's strange here... The puzzle is solved if we write the structure of…
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Acetylene and Acetylides

Acetylene and acetylides are easy to make and simple to understand. Acetylene (ethyne) is one of the tiniest organic compounds. Its formula is C₂H₂. The two carbon atoms share a triple bond. Its structure is HC≡CH. Acetylides are produced from acetylene by replacing one hydrogen atom. Acetylene is a useful fuel. Despite this, acetylene can form acetylides that are extremely dangerous, explosive! Making Acetylene Making the gas is simple. Mixing calcium carbide with water makes acetylene. CaC₂ + 2 H₂O → Ca(OH)₂ + C₂H₂↑ Calcium Carbide Where does calcium carbide come from? Lime and coke are combined at temperatures ranging from 2000 to 2100 degrees C in an electric arc furnace. CaO + 3C → CaC₂ + CO↑ [caption id="attachment_16272" align="alignright" width="280"] Calcium carbide[/caption] Triple Bond What is the origin of…
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