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Calcium + Water


Calcium is a silvery-white metal; it is relatively soft, but much harder than sodium metal.  Calcium is a member of the alkaline-earth metals (Group II on the periodic table); these metals react vigorously with water, although not as violently as the Group I metals such as sodium or potassium:

Ca(s)  +  2H2O(l)  ——>  Ca(OH)2(aq)  +  H2(g)


In the following demonstration, a chunk of calcium metal is dropped into a beaker of distilled water.  After a second or so, the calcium metal begins to bubble vigorously as it reacts with the water, producing hydrogen gas, and a cloudy white precipitate of calcium hydroxide.  The presence of the hydroxide is demonstrated by the addition of a few drops of phenolphthalein indicator, which turns the solution pink, indicating that the solution is basic.


Video Clip:  REAL, 4.31 MB



!!!  Hazards  !!!

Hydrogen gas is produced during the course of this reaction.  If you are not collecting the gas, perform the procedure in a fume hood or a well-ventilated area to allow the gas to dissipate.




Producing Hydrogen Gas from Calcium Metal:  Lee R. Summerlin, Christie L. Borgford, and Julie B. Ealy, Chemical Demonstrations:  A Sourcebook for Teachers, Volume 2, 2nd ed.  Washington, D.C.:  American Chemical Society, 1988, p. 51-52.




John Emsley, The Elements, 3rd ed.  Oxford, Clarendon Press, 1998, p. 48-49.

David L. Heiserman, Exploring Chemical Elements and their Compounds.  New York:  TAB Books, 1992, p. 84-87.

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