Question

What is meant by a pure substance?

Answer 1

Pure substance: A substance that consists of only one type of particle (atoms or molecules) is known as a pure substance.

• These particles are identical in all respects i.e.; physical and chemical properties.
• Example: Elements and compounds.
• Copper $\left(\mathrm{Cu}\right)$ is an element and a pure substance because copper only consists of copper particles (atoms) and no other particle is present apart from copper in it.
• Water $\left({\mathrm{H}}_2\mathrm{O}\right)$ is a compound and a pure substance because water only consists of water particles (molecules) and no other particle is present in it apart from water.