What energy change occurs during melting, and how does temperature behave during melting?

• A. Energy is released (exothermic); temperature rises.
• B. Energy is absorbed (endothermic); temperature decreases.
• C. Energy is absorbed (endothermic); temperature remains constant during melting.
• D. Energy is neither absorbed nor released; temperature fluctuates.

Answer: (C)

Melting requires energy input to overcome the forces holding a solid together. This energy input is absorbed from the surroundings and is endothermic.

During melting, the temperature stays the same at the melting point. The added heat goes into changing the arrangement of particles from a solid to a more fluid liquid, rather than increasing their average kinetic energy. As long as both solid and liquid are present, the temperature remains constant.

Once all the solid has melted, subsequent heat will raise the temperature of the liquid.

So, the energy is absorbed and the temperature remains constant during melting.