======Stoichiometry in Combustion of Acetylene======


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**Alternative titles:** Acetylene Combustion and Limiting Reagents
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====Summary====                   
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====Procedure====  
  - Fill a Pyrex® dish with water.  
  - Invert several borosilicate test tubes filled with varying amounts of water into the dish.  
  - Add one or two pellets of calcium carbide beneath each inverted tube to generate acetylene gas.  
  - Allow at least one tube to fill completely with acetylene and another to fill only partially.  
  - Remove each test tube individually and invert it over a burning splint to ignite the gas.  
  - Compare the intensity of combustion “pops” and the cleanliness of each test tube.



====Links==== 
Stoichiometry in Combustion of Acetylene - Flinn Scientific: 
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📄 Stoichiometry in Combustion of Acetylene - Flinn Scientific: [[https://www.flinnsci.com/api/library/Download/948a21160ad648c2a3c2cd9c4be36953?srsltid=AfmBOorYgCDl7DPu4wxulWAi7vhwz31ZNYwIJ1a4DHDVN6gbhsc8ozmY]]\\

====Variations====
  * Use a gas syringe to measure exact gas volumes for more quantitative stoichiometry studies.  
  * Test the combustion with different amounts of trapped air to refine the stoichiometric 5:2 oxygen-to-acetylene ratio.



====Safety Precautions====
  * Wear safety goggles, gloves, and a chemical-resistant apron.  
  * Perform the experiment in a well-ventilated area or fume hood.  
  * Keep all flames away from calcium carbide until gas collection is complete.  
  * Use only borosilicate test tubes free of cracks or chips to prevent breakage.  
  * Handle calcium carbide carefully; it is corrosive and reacts violently with moisture to release flammable gas.




====Questions to Consider====
  * What is the balanced chemical equation for the production of acetylene from calcium carbide? (CaC2 + 2H2O → C2H2 + Ca(OH)2)  
  * What is the balanced chemical equation for complete combustion of acetylene? (2C2H2 + 5O2 → 4CO2 + 2H2O)  
  * Why does a test tube filled entirely with acetylene burn weakly compared to one with both acetylene and oxygen? (Oxygen is the limiting reagent; without it, only incomplete combustion occurs at the tube’s opening.)  
  * What evidence indicates incomplete combustion? (Soot deposits and a weak, quiet flame.)  
  * Why does the correct oxygen-to-acetylene ratio produce a loud “pop”? (It allows complete combustion, releasing maximum energy rapidly.)