What role does thermal energy play in changing the state of a substance?

Thermal energy plays a crucial role in changing the state of a substance, primarily by influencing the kinetic energy of its particles. When thermal energy is transferred to a substance, it increases the energy of the molecules, causing them to move more rapidly. This increase in kinetic energy is essential for breaking intermolecular forces that hold molecules in a particular state, such as solid or liquid.

For example, when heating a solid, the added thermal energy allows the molecules to overcome their rigid arrangement and transition into the liquid state, where they can move more freely. Similarly, when a liquid is heated, the increased thermal energy enables the molecules to break free from their neighbors and enter the gaseous state.

This dynamic of promoting the change of state is fundamental to phase transitions such as melting, boiling, and vaporization, all of which require the input of thermal energy to occur. Therefore, the statement that thermal energy promotes the change of state accurately captures its essential role in phase transitions.