So they can predict what happens next
I believe the answer is the poles of the magnet.
Answer is: Yes it is balanced. It has the same number of Ca and O on both the reactant side and the product side.
According to principle of mass conservation, number of atoms must be equal on both side of chemical reaction.
There is one calcium atom atom and one oxygen atom on both side of reaction, so chemical reaction is balanced.
d, one atom of oxygen and two atoms of hydrogen
