The heat of fusion for silver at $960.8{ }^{\circ} \mathrm{C}$ is $88.3 \mathrm{~kJ} / \mathrm{kg}$ and the specific heat of silver is $0.235 \mathrm{~kJ} / \mathrm{kg}{ }^{\circ} \mathrm{C}$. What is the energy needed to melt 100 grams of silver starting at $0{ }^{\circ} \mathrm{C}$ ?

Question

Quizplus · Accepted Answer

The energy needed to melt the silver is the heat of fusion, which is $88.3 \mathrm{~kJ} / \mathrm{kg}$. The energy needed to raise the temperature of the silver from $0{ }^{\circ} \mathrm{C}$ to $960.8{ }^{\circ} \mathrm{C}$ is:$$Q = mc_p \Delta T = (0.1 \mathrm{~kg})(0.235 \mathrm{~kJ} / \mathrm{kg}{ }^{\circ} \mathrm{C})(960.8{ }^{\circ} \mathrm{C} - 0{ }^{\circ} \mathrm{C}) = 22.6 \mathrm{~kJ}$$The total energy needed is the sum of the heat of fusion and the energy needed to raise the temperature, which is $88.3 \mathrm{~kJ} + 22.6 \mathrm{~kJ} = 110.9 \mathrm{~kJ}$.

The Heat of Fusion for Silver At 960.8∘C960.8{ }^{\circ} \mathrm{C}960.8∘C Is 88.3 kJ/kg88.3 \mathrm{~kJ} / \mathrm{kg}88.3 kJ/kg

The Heat of Fusion for Silver At $960.8{ }^{\circ} \mathrm{C}$ Is $88.3 \mathrm{~kJ} / \mathrm{kg}$