Question
Explain how the addition of heat energy affects the states of matter, including what happens to particle speed, spacing, and energy during melting and boiling. Use examples from physical and chemical properties to support your explanation.
When heat energy is added to a substance, particles gain energy and move faster. During melting, a solid absorbs heat, causing particles to vibrate more vigorously until they overcome fixed positions and spread farther apart, changing into a liquid. During boiling, the liquid particles gain enough energy to break free from intermolecular forces entirely, becoming gas with much greater spacing and speed.