The constituents of a compound can be separated easily by physical methods.

The constituents of a compound cannot be separated by physical methods.

By chemical methods we can separate the components into individuals.

  ${\text{H}}_{\text{2}}\left(\text{g}\right)+1/2{\text{\hspace{0.17em}O}}_{\text{2}}\left(\text{g}\right)\to {\text{\hspace{0.17em}\hspace{0.17em}\hspace{0.17em}H}}_{\text{2}}\text{O\hspace{0.17em}}\left(l\right)$