Freezing involves which change and energy transfer?

Freezing involves which change and energy transfer?

• A. Liquid to solid; energy released.
• B. Solid to liquid; energy absorbed.
• C. Gas to solid; energy released.
• D. Liquid to solid; energy released.

Answer: (D)

Freezing is the change from a liquid to a solid. As the liquid cools, its particles lose energy and slow down enough to lock into a fixed, orderly structure. That loss of energy is released to the surroundings, so freezing is exothermic. So describing freezing as liquid turning into solid with energy released matches both the direction of the state change and the heat transfer. The other scenarios don’t describe freezing: solid to liquid would require energy input (melting, which is endothermic), and gas to solid is deposition from a gas to a solid, which is a different process.

Freezing is the change from a liquid to a solid. As the liquid cools, its particles lose energy and slow down enough to lock into a fixed, orderly structure. That loss of energy is released to the surroundings, so freezing is exothermic. So describing freezing as liquid turning into solid with energy released matches both the direction of the state change and the heat transfer.

The other scenarios don’t describe freezing: solid to liquid would require energy input (melting, which is endothermic), and gas to solid is deposition from a gas to a solid, which is a different process.