The copper is at its melting point. The melting point is the temperature a solid melts into a liquid. It is also the temperature that the liquid freezes into a solid. The problem statement wants to know the delta H for freezing copper starting at its melting point. Since the melting point and freezing point are the same point (same temperature), no temperature change takes place. The only things we need to know for this question are the Hfus(1083 °C) = 13.0 kJ/mol, the molecular mass of Cu=63.55, and the number of grams.
Grams to moles:
Then the delta H for freezing:
0.55075molX(-13.0)KJ/mol=-7.15975KJ = -7.16Kj to 3 significant figures.
Note that freezing is the negative of melting.