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Question

The enthalpy of fusion for aluminum metal is 10.9kJ/mol. How much heat is required to melt 9.75g of solid aluminum metal at its melting point? Report your answer in units of kJ. (Show steps)

Answer 1

The enthalpy of fusion is the amount of heat needed to melt or freeze 1 mole of a substance at it's freezing/melting point. For aluminum (Al), this is 10.9 kJ / mole. So we need to find how many moles of Al we have in 9.875 g of Al.

mols Al = 9.875 g Al x 1 mol Al / 26.98 g = 0.3660 mols Al

heat required to melt this at the melting point = 0.3660 mols x 10.9 kJ / mol = 3.99 kJ