It can only be extracted from the deep mountains after being struck by thousands of hammers. It regards the burning of the burning fire as a very common thing.
Don't be afraid of being smashed to pieces, leaving innocence in the world.
The first sentence is physical change,
The chemical equations corresponding to the last three sentences are as follows:
CaCO3=CaO+CO2↑，
Calcium oxide +H2O = calcium hydroxide,
Calcium hydroxide+carbon dioxide = calcium carbonate ↓+H2O.