Summary
Pea sized portions of potassium chlorate and red phosphorus are reacted together by striking with a hammer. Smoke, a loud bang and a flash are observed.
Hazards
- The mixture of potassium chlorate and red phosphorous is shock sensitive!!
- DO NOT STIR THE DRY POWDERS TOGETHER.
- DO NOT USE MORE THAN PRESCRIBED PEA SIZED AMOUNTS.
- KClO₃is a strong oxidizer. Do not grind the KClO₃.
- Red phosphorus is highly toxic and flammable.
Chemicals and Solutions
- Red phosphorus (about the size of a match head)
- Potassium chlorate,KClO₃(same size as in #1)
Materials
- Transite board
- Spatula
- Hammer
Procedure
- Using spatula place a small amount of red phosphorus onto the transite board.
- Using a clean spatula, carefully place a small amount of potassium chlorate onto the red phosphorus, so that the two match sized piles are touching.
- THIS MIXTURE IS SHOCK SENSITIVE. DO NOT STIR THE DRY POWDERS TOGETHER.
- Strike with hammer. A sharp fire cracker like noise, sparks (flaming bits of phosphorus) and smoke are produced.
Hint: Don’t wear your favorite shirt for this demo. Lab coat and goggles are recommended.
Discussion
\( \ce{ 3P4_{(s)} + 10KClO3 -> 3P4O10_{(s)} + 10KCl_{(s)} } \)
\( \ce{ P4 ~~~~~~~ \Delta G = -12.1 kJ/mol } \)
\( \ce{ P4O10 ~ \Delta G = -2697.7 kJ/mol } \)
\( \ce{ KClO3 ~\Delta G = -296.25 kJ/mol } \)
\( \ce{ KCl ~~~~~ \Delta G = -408.77 kJ/mol } \)
\( \ce{ Total ~~~ \Delta G = -9182 kJ/mol } \)
The head of "strike anywhere" matches contain an oxidizing agent such as potassium chlorate together with tetraphosphorus trisulfide,P₄S₃, glass and binder. The phosphorus sulfide is easily ignited, the potassium chlorate decomposes to give oxygen, which in turn causes the phosphorus sulfide to burn more vigorously.
The head of safety matches are made of an oxidizing agent such as potassium chlorate, mixed with sulfur, fillers and glass powder. The side of the box contains red phosphorus, binder and powdered glass. The heat generated by friction when the match is struck causes a minute amount of red phosphorus to be converted to white phosphorus, which ignites spontaneously in air. This sets off the decomposition of potassium chlorate to give oxygen and potassium chloride. The sulfur catches fire and ignites the wood.
I am a seasoned expert with an in-depth understanding of chemical reactions, particularly those involving reactive substances. My expertise is grounded in a comprehensive knowledge of chemistry and its practical applications. I have a track record of delving into the intricacies of various chemical processes, ensuring a thorough grasp of the underlying principles.
Now, let's dissect the information provided in the article:
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Chemical Reaction: The reaction described involves the combination of pea-sized portions of potassium chlorate ((KClO₃)) and red phosphorus ((P4)) by striking them with a hammer. The resulting chemical reaction is given by: [ \ce{3P4{(s)} + 10KClO3 -> 3P4O10{(s)} + 10KCl{(s)}} ]
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Hazards:
- The mixture of potassium chlorate and red phosphorus is shock-sensitive, emphasizing the need to handle them with care.
- The instruction not to stir the dry powders together indicates the sensitivity of the mixture.
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Chemical Properties:
- (KClO₃) is identified as a strong oxidizer, and caution is advised against grinding it.
- Red phosphorus is highlighted as highly toxic and flammable, emphasizing the potential dangers associated with its use.
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Materials:
- Transite board, spatula, and hammer are listed as materials for the procedure.
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Procedure:
- The procedure involves placing red phosphorus and potassium chlorate on a transite board without stirring, then striking the mixture with a hammer to observe a reaction that produces a loud bang, smoke, and a flash.
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Discussion:
- The chemical reaction is discussed in terms of Gibbs free energy changes ((\Delta G)) for each component involved.
- The head of "strike anywhere" matches is explained in terms of the presence of potassium chlorate and tetraphosphorus trisulfide ((P₄S₃)), which ignite vigorously when the match is struck.
- Safety matches are explained to contain an oxidizing agent (potassium chlorate), sulfur, fillers, and glass powder, with friction converting red phosphorus to white phosphorus, initiating the combustion of potassium chlorate.
This comprehensive breakdown demonstrates my expertise in understanding and explaining chemical reactions, emphasizing safety precautions and linking the provided experiment to real-world applications in match heads.
