Question

Question #65477

Answer 1

It means that you have the same number of atoms on each side of the equation.

Explanation:

`2"H"_2 + "O"_2 -> 2"H"_2"O"`

On the reactants side, you have `4` hydrogen atoms and `2` oxygen atoms. On the products side, you also have `4` hydrogen atoms and `2` oxygen atoms.