Final answer:
To calculate the heat of fusion in kJ/mol, use the enthalpy of fusion specific to the substance (like 6.0 kJ/mol for ice), then multiply the number of moles by this enthalpy value. Ensure all units are consistent, converting joules to kilojoules if necessary.
Step-by-step explanation:
To calculate the heat of fusion in kilojoules per mole (kJ/mol), you need to know the amount of energy required to melt one mole of a substance at its melting point without any change in temperature. This is also known as the enthalpy of fusion (ΔHfus). For example, the enthalpy of fusion for ice at 0 °C is 6.0 kJ/mol.
Assuming you have the mass of the substance in grams and its molar mass, you can convert the mass into moles and then multiply by the substance's known heat of fusion. If you are measuring the heat in joules, ensure to convert it to kilojoules by dividing by 1000. The heat of fusion is determined under constant pressure and results from energy absorbed to disrupt intermolecular forces during the phase change from solid to liquid.
As an example, melting 1 mol of ice at 0°C would require 6.0 kJ of energy, as fusion is an endothermic process where energy is absorbed from the surroundings.