Calcium carbonate (CaCO3) is a metal carbonate compound and reacts with hydrochloric acid (HCl) to produce carbon dioxide (CO2), calcium chloride (CaCl2) and water. You can see, carbon dioxide gas is released through the solution.
Calcium carbonate is not soluble in water and exists as white precipitate in the water. When aqueous hydrochloric acid is added, calcium chloride, carbon dioxide and water are formed.
This reaction is used to calculate purity of CaCO3 samples when they are mixed with impurities.
If impurity material does not react with dilute hydrochloric acid, You can conduct this experiment. Released carbon dioxide volume is measured and then calculate the released amount (mol) of carbon dioxide gas. Then, you can calculate the reacted calcium carbonate amount and mass.
When calcium carbonate reacts with hydrochloric acid, heat is released to the environment.
Questions asked by students
If heat is released from a reaction, it means products of the reactions are more stable than reactants. When something is stable, it should have less energy. When HCl reacts with calcium carbonate, calcium chloride and carbon dioxide gas are given.
When you are said to write balanced equation, remember that to write physical properties of compounds.
CaCO3(s) + 2HCl(aq) → CaCl2(aq) + CO2(g) + H2O(l)
Calcium carbonate reacts with dilute acids to produce a calcium salt, water and carbon dioxide gas: calcium carbonate + hydrochloric acid → calcium chloride + water + carbon dioxide.
Calcium chloride, carbon dioxide and water are given as products.
Both carbonates are not insoluble in water and form white precipitates. Calcium carbonate and zinc carbonate reacts with dilute hydrochloric acid and emit carbon dioxide gas form colorless solutions. (CaCl2 and ZnCl2 are colorless solutions).
But, treating hydrogen sulfide gas to calcium chloride and zinc chloride can be used to identify solutions. Calcium sulfide is soluble in water. But, ZnS is not a soluble sulfide in water and form a white precipitate.