Calcium carbonate can be identified by its chemical property of reacting with acids to produce carbon dioxide gas. This reaction can be observed by adding a few drops of hydrochloric acid to a sample of calcium carbonate. If the sample is calcium carbonate, it will fizz and release carbon dioxide gas. This reaction can be represented by the following equation:

CaCO3(s) + 2HCl(aq) → CO2(g) + CaCl2(aq) + H2O(l)

This chemical property can be used to identify calcium carbonate in a variety of settings, such as in geology, chemistry, and environmental science. It can also be used to test for the presence of calcium carbonate in water samples, such as those used for drinking or irrigation.