Answer:
Step-by-step explanation:
Compounds are pure substances formed by two or more different kind of atoms.
For example, H₂O, and CaCO₃ are compounds.
- H₂O can be separated into hydrogen (H₂) and oxygen (O₂) only by a chemical change.
- CaCO₃ can be separated into CaO and CO₂ only by a chemical change.
Elements can not be separated into other substances by a chemical change. The process to change an element into other substance (different element) is a nuclear reaction (transmutation).
Mixtures are not pure substances and can be separated into other substances by physical changes: for example, a brine can be separated into salt and water by evaporation.