The heat of fusion of a substance is the amount of heat needed to change 1 kg of it at its melting point from the solid to the liquid state.
(The heat of fusion of a substance; is; the amount of heat needed) (the amount of heat; needed; to change 1 kg of it at its melting point from the solid to the liquid state)
The heat of fusion of a substance the amount of heat
is needed
the amount of heat needed
to change 1 kg of it at its melting point from the solid to the liquid state