Why is this chemical equation not balanced H2 O2 H2O?

Answer 1

Because there are 2 oxygen atoms on the reactants side and only one on the products side. You can either add a coefficient of 1/2 on the O2 or you can add a coefficient of 2 on H2 and H2O.

Answer 2

This chemical equation is not balanced because the number of hydrogen atoms on the reactant side (2) does not equal the number on the product side (2 in H2O). Similarly, the number of oxygen atoms on the reactant side (2) does not equal the number on the product side (1 in H2O). Balancing the equation would involve adjusting the coefficients in front of the molecules to ensure that the number of atoms of each element is the same on both sides of the equation.