Dry ice (solid carbon dioxide) sublimates directly into carbon dioxide gas at a constant temperature of −78.5∘C-78.5^\circ\text{C}−78.5∘C. Which statement correctly describes the changes in the average kinetic energy and the potential energy of the carbon dioxide molecules during this transition?
The average kinetic energy of the molecules increases, and their potential energy remains constant.
The average kinetic energy of the molecules remains constant, and their potential energy increases.
The average kinetic energy of the molecules remains constant, and their potential energy decreases.
Both the average kinetic energy and the potential energy of the molecules increase.
27 exam-style questions on OCR GCSE Chemistry The particle model. Each one has a worked solution and a mark scheme showing where the marks go.