Final answer:
When water is heated from 280 K to 310 K, its molecules move faster due to an increase in thermal energy, which results in an increase in the average kinetic energy of the molecules.
Step-by-step explanation:
As the temperature of water rises from 280 K to 310 K, the average kinetic energy of its molecules increases. This is because temperature is a measure of the average kinetic energy of the particles in a substance. When water is heated, the molecules gain energy and move faster, which results in an increase in kinetic energy.
Kinetic Energy and Temperature
Thermal energy, or heat, causes particles to vibrate, rotate, and move more vigorously. The relationship between temperature and kinetic energy is direct; as one goes up, so does the other. An increase in temperature from 280 K to 310 K means a definite increase in the kinetic energy of the molecules.
Moreover, during heating, the energy that is input into the system does not go into a change of state, but instead increases the molecular motion until a phase transition point is reached. Before this point, nearly all the added energy contributes to the increased kinetic energy of the water molecules, not to a change in state or temperature.