The heat of fusion is the energy necessary to transform 1 gram of the solid compound in its liquid phase. Fusion requires that the systems gain heat, so it's an endothermic process.
The energy (Q) is relacionated to the mass of the compound (m) and its heat of fusion (L):
Heat fusion is the amount of energy required to convert one mole of ice into water, 16650J is per 50g so if we divide 16650 by 50 we find it per gram: 16650/50 = 333J/g or 0.33KJ/g
