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Zinc + Sulfur


Zinc is a bluish-white metal used to galvanize iron, and is also found in alloys, batteries, and rubber.  Sulfur is a yellow, brittle nonmetal; it can also be found in a powered form.  Zinc and sulfur react with each other violently to produce zinc sulfide; the reaction is accompanied by a vigorous evolution of gas, heat, and light:

Zn(s)  +  S(s)  ——>  ZnS(s) [one of the easier 
chemical equations 
to balance!]

The products of the reaction also include small amounts of zinc oxide (ZnO) and sulfur dioxide (SO2).

This reaction produces enough hot gas to propel small rockets; this was one of the model rocket propellants described by Homer Hickam in his book Rocket Boys (Delacorte Pr; 1998) [filmed as October Sky (Universal Studios, 1999)].


In the first demonstration below, powdered zinc and sulfur are mixed in a porcelain evaporating dish and heated with a flame; the mixture burns with a yellowish-green flame, and leaves a residue of yellow zinc sulfide in the dish.  In the second video clip, a larger sample is ignited in an evaporating dish, which shatters; and in the third clip, a similar mixture cracks a large porcelain crucible.


Video Clip 1:  REAL, 3.33 MB



Video Clip 2:  REAL, 1.41 MB



Video Clip 3:  REAL, 2.62 MB



!!!  Hazards  !!!

This reaction produces a great deal of heat energy; clear the area of flammable materials.

This reaction must be performed in a fume hood or some open, well-ventilated area.  If you do this in a fume hood, be prepared to spend some time wiping zinc sulfide powder off all of the surfaces in the hood. 




Bassam Z. Shakhashiri, Chemical Demonstrations: A Handbook for Teachers of Chemistry, Volume 1.  Madison: The University of Wisconsin Press, 1983, p. 53-54.




John Emsley, The Elements, 3rd ed.  Oxford, Clarendon Press, 1998, p. 120-121, 198-199.

David L. Heiserman, Exploring Chemical Elements and their Compounds.  New York:  TAB Books, 1992, p. 65-69, 122-124.

Martha Windholz (ed.), The Merck Index, 10th ed. Rahway: Merck & Co., Inc., 1983.