Medical Chemistry Practice Test

Freezing is the process by which a liquid becomes a solid. As temperature falls, the particles lose kinetic energy and the attractive forces bind them into a fixed, orderly arrangement, creating a solid structure. This phase change releases energy, known as latent heat of fusion, because the system becomes more ordered. Melting is the opposite (solid to liquid), boiling is liquid to gas, and condensation is gas to liquid, so those involve different directional changes of state. For many liquids like water, freezing occurs near 0°C under standard pressure, though impurities or pressure can shift the exact point.