Question

a chemist is studying an unknown substance he can break it into its elemental only by using chemical means.Based on this observation, how should the unknown substance be classified

Answer 1

Compound

Step-by-step explanation:

We want to know if it's a compound or a mixture.

An example of a mixture is salt water: you can heat it hot enough to boil off the water, leaving only the salt. This is a physical change, which is how you know it's a mixture.

Something like gold is a compound: if you heat it, or hit it, you'll still only have gold. You can only break it down by chemical means, which is how you know it's a compound.