The heat of fusion for lead at 327.0°C is 22.9 kJ/kg and the specific heat of lead is 0.130 kJ/kg∙°C1. To calculate the energy needed to melt 100 grams of lead starting at 0°C, we can use the following formula:
Energy needed = (mass of lead) x (heat of fusion) + (mass of lead) x (specific heat) x (change in temperature)
Substituting the values we get:
Energy needed = (100 g) x (22.9 kJ/kg) + (100 g) x (0.130 kJ/kg∙°C) x (327°C - 0°C)
Energy needed = 2,290 J + 4,251 J
Energy needed = 6,541 J
Therefore, it would take 6,541 J of energy to melt 100 grams of lead starting at 0°C12.