Question

When we heat iron filing and sulphur till red hot, do we get a compound or a mixture?

Answer 1

Mixture:

1. A mixture is a substance which consists of two or more pure substances(elements or compounds) mixed together in any proportion so that components do not lose their identity.
2. For example, seawater, petrol, soil, soft drinks and air is a mixture of several gases.

Compound:

1. A compound is a pure substance made up of two or more elements chemically combined with one another in a fixed proportion by mass.
2. Example- ${\mathrm{H}}_2\mathrm{O}$ is composed of two elements: hydrogen and oxygen.
3. When iron filings and sulphur powder are mixed and heated they undergo a chemical reaction and form ferrous sulphide $\left(\mathrm{FeS}\right)$.
4. The chemical reaction is $$\begin{gathered} \mathrm{Fe}\left(\mathrm{s}\right)+{\mathrm{S}}_{}\left(\mathrm{s}\right)\stackrel{\mathrm{Heating}}{\to }\mathrm{FeS}\left(\mathrm{s}\right) \\ \left(\mathrm{Iron}\right)\left(\mathrm{Sulphur}\right)(\mathrm{Iron}\mathrm{sulphide}) \end{gathered}$$
5. It is a new substance which has properties entirely different from iron ($\mathrm{Fe}$) and sulphur ($\mathrm{S}$), the iron sulphide compound cannot be separated into its constituents by physical methods.

Hence, when we heat iron filing and sulphur till red hot a compound is formed.