1. The thermal decomposition of calcium carbonate (if you think to this reaction) is not an acid-base reaction.
2 The calcium oxide is not oxidized by oxygen.
22.0g
decomposition
An endothermic reaction, because it uses heat. If it gave off heat it would be exothermic.
CaCO3 + 2H2O = Ca(OH)2 + H2O + H2 NB The water is acting as a very weak acid. It is a very slow reaction; So you won't see anything happening.
NaCl plus CaCO3 plus water
22.0g
2hcl
decomposition
An endothermic reaction, because it uses heat. If it gave off heat it would be exothermic.
CaCO3+2HCl----->CaCl2+H2O+CO2
Acid base reaction
Combination Reaction
CaCO3 + 2H2O = Ca(OH)2 + H2O + H2 NB The water is acting as a very weak acid. It is a very slow reaction; So you won't see anything happening.
Precipitate because you're making a solid out of two liquids.
NaCl plus CaCO3 plus water
An exothermic chemical reaction.
Carbonic acid and Calcium chloride are produced in the reaction between calcium carbonate and hyrdochloric acid. CaCO3 + 2HCl --> H2CO3 + CaCl2