Define and explain the standard enthalpy of vapourisation of sublimation.

Explanation

It is the enthalpy change accompanying the sublimation of one mole of a solid substance into gaseous state at a constant temperature below its melting point at the standard pressure.
Sublimation is direct conversation of a solid into vapour. The enthalpy of sublimation can be calculated with the help of less's law.
The enthalpy of sublimation is the sum of enthalpy of fustion and enthalpy of vapourisation.
`Delta_("sub")H-Delta_("fus")H+Delta_("vap")H`