Question

compounds can only be separated into their component elements by ___.
breaking chemical bonds
breaking element bonds
removing impurities

Explanation:

A compound is formed by the chemical combination of two or more elements. Chemical bonds hold the atoms of these elements together in a compound. To separate a compound into its component elements, these chemical bonds must be broken. Element bonds don't exist as elements are pure substances. Removing impurities is relevant for mixtures, not for separating compounds into elements.

Answer:

breaking chemical bonds