Which term describes the energy required to change a solid to a liquid at the melting point without a temperature change?

• A. Heat
• B. Heat Capacity
• C. Latent Heat of Vaporization
• D. Latent Heat of Fusion

Answer: (D)

The concept here is latent heat of fusion. When a solid at its melting point absorbs energy, its temperature stays the same while the energy goes into breaking the bonds that hold the solid together, allowing it to become a liquid. That’s why no temperature change accompanies the solid-to-liquid transition at the melting point. Once melting is complete, any further energy will raise the liquid’s temperature (sensible heat). Heat is just general energy transfer due to temperature difference, and latent heat of fusion specifically describes this solid-to-liquid change.