sample of substance X 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?
Number of moles ( substance x ):
1 mole --------- 58.45 g/mol
? mole --------- 326.0 g
326.0 x 1 / 58.45 => 5.577 moles
heat of fusion:
hf = Cal / moles
hf = 4325.8 Cal / 5.577 moles
hf = 775.65 cal/mol
hope this helps!