Final answer:
The addition or removal of thermal energy affects particle motion, temperature, and state of a substance. Increased thermal energy raises particle motion and temperature, potentially causing a state change like melting, while energy removal may lead to freezing. These processes are governed by the balance of kinetic energy and intermolecular forces.
Step-by-step explanation:
The motion of particles, temperature, and state of a pure substance are closely related to each other and are influenced by the addition or removal of thermal energy. The state of a substance, whether gas, liquid, or solid, is influenced by both kinetic energy, which affects particle motion, and intermolecular forces. When thermal energy is added to a substance, the kinetic energy of its particles increases, causing the particles to move more rapidly. This can lead to a change in the state of the substance, such as melting or vaporizing. Conversely, removing thermal energy reduces the particles' kinetic energy, which can result in a state change like condensation or freezing.
Increase in temperature due to addition of thermal energy leads to more extensive vibrations in solids and rapid movement in liquids and gases. Higher temperatures also mean a more dispersed distribution of kinetic energies among the particles, increasing entropy. Conversely, decreasing thermal energy lowers the temperature and reduces particle motion and entropy. The balance between kinetic energy and intermolecular forces determines the state of a substance, and changing this balance via thermal energy can cause a state change.