Question

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?

Answer 1

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_2O_2(aq) rarr H_2O(aq) + 1/2O_2(g)uarr`

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(-I)` in peroxide, has been reduced to water `O(-II)`, and oxidized to zerovalent oxygen gas `O_2(0)`.

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.