If the heat of fusion is 32.2 kj/mol, the amount of heat energy required to melt 5.67 grams of feo is

The heat of fusion is the amount of energy required to change the state of one mole of substance from solid to liquid at constant temperature. Therefore, in order to determine the energy needed by a given mass of substance, we must first convert the mass into moles by using:

Moles = mass / Mr

Moles = 5.67 / 71.84

Moles = 0.079 mol

Energy = latent heat of fusion * moles

Energy = 32.2 * 0.079

Energy = 2.544 kJ = 2,544 J