Question

The normal melting point of copper is 1357 K and heat of fusion of Cu is 13.05 KJ.

How much heat, in kilojoules, is evolved when a 3.70 kg sample of of molten Cu freezes?

Answer 1

Your heat of fusion should have units of kJ/mole NOT just kJ. I had to look it up so see what it is.

So, you must determine how many moles of copper are in 3.70 kg. (3700 g)
You will need to remember or look up the atomic weight of copper to do that.

Then multiply that number of moles by 13.05 kJ/mole.