The cooling curve of a pure liquid has a horizontal section. Why does the temperature stay constant during that section?
The energy transferred away from the liquid becomes zero while it freezes
The kinetic energy store of the particles increases as the bonds are formed
Energy is released as bonds form, balancing the energy transferred away
The thermometer cannot respond quickly enough while the liquid freezes
40 exam-style questions on AQA GCSE Physics 3.2 Internal energy and energy transfers, covering 3.2.1 Internal energy, 3.2.2 Temperature changes in a system and specific heat capacity, and 3.2.3 Changes of state and specific latent heat. Each one has a worked solution and a mark scheme showing where the marks go.