# The heat of fusion for Al is 125 Jg^-1. How do you calculate the molar heat of fusion for Al?

The key thing needed is to know the molar mass of aluminium: $27$ gmol^−1. If each gram of aluminium takes $125$ $J$ to vaporise it, and a mole is $27$ $g$, then each mole takes 27×125=3,375 Jmol^−1.