Asample of substance x that has a mass of 326.0 g releases 4325.8 cal when it freezes at its freezing point. if substance x has a molar mass of 58.45 g/mol, what is the molar heat of fusion for substance x?

1) Calculate the number of mols,n,  of the substance

n = mass/ molar mass = 326.0 g / 58.45 g / mol = 5.577 moles

2) Calculate the molar heat of fusion as the total heat released by the sample divided by the number of moles

hf = heat released / n = 4325.8 cal / 5.577 moles = 775. 59 cal /mol