The heat of fusion for a solid is .825kJ/mole. the formula weight of the solid is 150.24. How many grams of this solid can be melted by 305J of energy?
q = moles x heat fusion in kJ/mol
I would change 305 J to kJ, substitute for q and solve for number of moles that can be melted.
Then n = grams/molar mass and solve for grams.