When 100 g of methane gas condenses, 51 kJ of energy is released.
When 100 g of liquid methane freezes, 5.9 kJ of energy is released.
Which statement explains why condensation releases much more energy than freezing?
The intermolecular attractions present in liquid methane disappear as the solid forms, limiting the energy released during freezing.
Condensation combines methane molecules into larger molecules, increasing the energy released; freezing changes only their arrangement.
A 100 g sample contains more methane molecules in the gas state than in the liquid state, so condensation affects more molecules.
When methane condenses, molecules that were widely separated become much closer, creating a larger change in intermolecular attractions than freezing does.
122 exam-style questions on OCR GCSE Chemistry 2.3 Properties of materials, covering 2.3.1 Carbon bonding and the variety of organic compounds, 2.3.2 Diamond, graphite, fullerenes and graphene, 2.3.3 Bond strength, changes of state and predicting states, 2.3.4 Bulk properties and types of bonding, and 2.3.5 Nanoparticles: scale, surface area, uses and risks. Each one has a worked solution and a mark scheme showing where the marks go.