4. Which of the following BEST explain the physical changes in terms of the arrangement and motion of atoms and molecules during boiling point? A. Molecules on the surface of a liquid break away and change into gas. B. Reverse reaction in which a gas changes directly to solid without passing through the liquid state. C. Substances change from solid to gas without passing through the liquid state. D. Temperature is reached at which vapor pressure of a liquid equals the external pressure surrounding the liquids.

5. Which of the following BEST explain the physical changes in terms of the arrangement and motion of atoms and molecules during freezing point? A. A reverse reaction in which a gas changes directly to solid without passing through the liquid state. B. A reverse process also happens when liquid turns into a solid. In this process heat is removed from liquid C. Substances change from solid to gas without passing through the liquid state. D. Temperature is reached at which vapor pressure of a liquid equals the external pressure surrounding the liquids.​