When water freezes into ice, what is the sign of the change in entropy (ΔS) and why?

• A. ΔS is zero because the process is at equilibrium.
• B. ΔS is positive because the molecules become more disordered.
• C. ΔS is negative because the molecules become more ordered.
• D. ΔS is positive because energy is absorbed.

Answer: (C)