An open beaker of ethanol is left on a laboratory bench, and the level of the liquid gradually decreases.
Which statement molecularly explains why the liquid level decreases?
The least energetic molecules escape from the surface of the liquid and then return.
The least energetic molecules escape from the surface of the liquid and do not return.
The most energetic molecules escape from the surface of the liquid and then return.
The most energetic molecules escape from the surface of the liquid and do not return.
528 exam-style questions on CIE IGCSE Physics 2.2 Thermal properties and temperature, covering 2.2.1 Thermal expansion of solids, liquids and gases, 2.2.2a Internal energy and temperature, 2.2.2b Specific heat capacity, 2.2.3a Melting, boiling, condensation and solidification, 2.2.3b Evaporation, and 2.2.3c Cooling by evaporation. Each one has a worked solution and a mark scheme showing where the marks go.