After a strenuous workout, an athlete cools down as sweat evaporates from their skin. Which molecules escape from the surface of the sweat, and what happens to the average kinetic energy of the remaining sweat molecules?
The more energetic molecules escape, and the average kinetic energy of the remaining molecules decreases.
The more energetic molecules escape, and the average kinetic energy of the remaining molecules increases.
The less energetic molecules escape, and the average kinetic energy of the remaining molecules decreases.
The less energetic molecules escape, and the average kinetic energy of the remaining molecules increases.
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.