The following balanced equation shows the decomposition of water (h2o). according to the equation, how many oxygen atoms are in the reactants? 2 h2o 2h2 + o2

There are 2 oxygen atoms on the reactant side.

Explanation:

Every balanced chemical equation follows law of conservation of mass.

This law states that mass can neither be created nor be destroyed, but it can only be transformed from one form to another form.

This law also means that total number of individual atoms on the reactant side will always be equal to the total number of individual atoms on the product side.

The given balanced chemical equation follows:

On reactant side:

Number of hydrogen atoms = 4

Number of oxygen atoms = 2

On  product side:

Number of hydrogen atoms = 4

Number of oxygen atoms = 2

Hence, the number of oxygen atoms on the reactant side is equal to 2.