What is the balanced chemical equation for CaCO3 to CaO plus CO2?

The equation is already balanced:

CaCO3(s) --> CaO(s) + CO2(g)


A balanced chemical equation is one where the number of atoms on both sides are equal. Chemical equations must be balanced because there is only a rearrangement of atoms in a reaction so the number of atoms you start off with must be the same as the number of atoms you end up with.

If we take a look at the equation, we can see that there is 1 calcium atom, 1 carbon atom and 3 oxygen atoms present on both sides. As the number of these atoms on both sides are equal, the equation is balanced.