Latent Heat in Phase Changes

Steps:

• Recall that melting ice (solid to liquid) and boiling water (liquid to gas) are phase transitions requiring energy input.
• Identify that energy for these changes is latent heat, absorbed without temperature rise.
• Evaluate options: A checks volume changes, B checks temperature effects, C checks heat absorption, D checks forces.
• Select C as it matches the defining feature of both processes.

Why C is correct:

• Latent heat is the energy absorbed during phase changes to overcome intermolecular forces, as defined in thermodynamics, without altering temperature.

Why the others are wrong:

• A: Melting ice decreases volume slightly, but boiling increases it dramatically.
• B: Energy transfer occurs, but temperature remains constant during the phase change.
• D: Both processes weaken intermolecular forces, increasing molecular disorder.

Final answer: C