Question

Define pure substances. Give two examples.

Answer 1

Defining pure substances

1. When a substance is made up of only one kind of particle, it is called a pure substance. These particles may be atoms or molecules.
2. Hence, we can define a pure substance as the substance that is made up of only one kind of atom or one kind of molecule.
3. Elements and compounds are two types of pure substances.
4. Any other substance made by the combination of different elements and compounds are known as mixtures.

Example:-

1. The elements such as Oxygen$\left(\mathrm{O}\right)$, Nitrogen$\left(\mathrm{N}\right)$, Hydrogen$\left(\mathrm{H}\right)$, Chlorine$\left(\mathrm{Cl}\right)$, and Bromine $\left(\mathrm{Br}\right)$ are all pure substances because they contain only one kind of particle.
2. Compounds such as water $\left({\mathrm{H}}_2\mathrm{O}\right)$ in the form of ice and steam, Carbon dioxide$\left({\mathrm{CO}}_2\right)$, Sodium chloride$\left(\mathrm{NaCl}\right)$, etc are pure substances.