# Hydrogen peroxide (H_2O_2) breaks down into water (H_2O) and oxygen (O_2). Explain why this is a chemical reaction. What are the reactants and the products in the reaction?

Oct 1, 2016

Chemical change is characterized by the formation of new products and the making and breaking strong chemical bonds.

#### Explanation:

We need a chemical equation:

${H}_{2} {O}_{2} \left(a q\right) \rightarrow {H}_{2} O \left(a q\right) + \frac{1}{2} {O}_{2} \left(g\right) \uparrow$

Mass and charge are balanced as they must be (why; what do I mean here?). This is in fact a disproportionation reaction because the $O \left(- I\right)$ in peroxide, has been reduced to water $O \left(- I I\right)$, and oxidized to zerovalent oxygen gas ${O}_{2} \left(0\right)$.

At any rate, the decomposition clearly features the breaking of $O - O$ bonds, and the formation of $O = O$ bonds; this is manifestly a chemical change.