Question

a chemist is studying an unknown substance and could break the substance into its elemental components only by using chemical means. based on this observation, how should the unknown substance be classified? impure substance solution mixture pure substance

Explanation:

A pure substance can be broken into its elemental components only by chemical means. An impure substance (mixture) can be separated into its components by physical means. A solution is a homogeneous mixture (can be separated physically). A mixture (in general) can be separated by physical methods.

Answer:

pure substance