The heat of fusion for lead at 327.0$^{\circ}$C is 22.9 kJ/kg and the specific heat of lead is 0.130 kJ/kg$^{\circ}$C.What is the energy needed to melt 100 grams of lead starting at 0$^{\circ}$C?

Question

Quizplus · Accepted Answer

First, we need to calculate the energy needed to raise the temperature of 100 grams of lead from 0°C to its melting point at 327°C.
Q1 = m * Cp * ΔT = 100 g * 0.130 kJ/kg°C * (327°C - 0°C) = 4261 kJ

Next, we need to calculate the energy needed to melt 100 grams of lead.
Q2 = m * Hf = 100 g * 22.9 kJ/kg = 2290 kJ

The total energy needed is the sum of Q1 and Q2:
Q = Q1 + Q2 = 4261 kJ + 2290 kJ = 6551 kJ

We need to convert kJ to J to match the answer choices:
Q = 6551 kJ * 1000 J/kJ = 6,551,000 J

The answer is C, 6.54 kJ.

The Heat of Fusion for Lead at 327 ∘^{\circ}∘ C Is 229 KJ/kg and the Specific Heat of Lead Is 0

The Heat of Fusion for Lead at 327 $^{\circ}$ C Is 229 KJ/kg and the Specific Heat of Lead Is 0