Question

You are heating water in a teapot on the stove. The water starts to boil, creating steam that makes the teapot whistle. Which of the following describes what happens to the water molecules during this process?

Answer 1

The fastest moving watermolecules in the liquid water escape the attraction of nearby molecules and come to move freely. As they escape they lose some kinetic energy. This cools the whole mixture of liquid and water enough to maintain the temperature at 100°C while energy from a heater is stille being added.