Question

Why an opening the box of camphor its smell spread all around

Answer 1

Camphor is a sublimate i.e. it evaporates quickly and changes directly from solid to gaseous state.On opening a box of camphor, it acquires the heat from it's surroundings and then it uses that energy to get evaporated while evaporating it get's spread throughout fast as it has kinetic energy in a large proportion due to intensive heat.