A simple demonstration of how a precipitate is evidence of a chemical reaction taking place is performed by mixing solutions of calcium chloride and sodium carbonate to form the precipitate calcium carbonate (CaCO3).
CaCl2(aq) + Na2CO3(aq) → CaCO3(s) + 2NaCl(aq)
To Conduct Demonstration
Demo Time: ~5 minute
Safety and Disposal
Wash your hands after demonstration. Calcium chloride is an irritant.
H.W. Hanna and A. Dittmar; Laboratory Manual for General Chemistry, 4th ed.; Morton Publishing Company, Denver, Colorado. (This demonstration has been altered, the original used barium chloride and potassium chromate, which are toxic. Reference is for original version.)
Laurel Hyde Boni, Kristin Boles