Final answer:
The particles of a substance change from being tightly packed in a solid, to flowing past each other in a liquid, and then moving freely in a gas as temperature increases and intermolecular forces are overcome.
Step-by-step explanation:
How Particles Change During Phase Transitions from Solid to Liquid to Gas
As a substance transitions from solid to liquid, and then to gas, the particles of the substance undergo significant changes. Starting as a solid, the particles are tightly packed in a rigid structure. Upon heating, these particles gain energy and vibrate more vigorously, weakening their binding forces, leading to a phase transition to a liquid where the particles are still close but can move and flow past each other.
Further heating supplies more energy to the particles, to the point where the intermolecular forces are completely overcome, and the particles separate widely, transitioning to a gas. This phase has particles that move freely and independently, occupying much more volume - by a factor of 1,000 or more - compared to the liquid state. The particle behavior and characteristics of these states reflect the balance between the energy of the particles and the intermolecular forces that exist within the substance at different temperatures.
During these phase changes, the volume of a substance normally does not change significantly when transitioning from solid to liquid, but the change from liquid to gas results in a substantial increase in volume. This is due to the significant reduction in intermolecular forces during vaporization, allowing the particles to occupy a greater amount of space. These changes in states of matter are physical changes that do not alter the chemical composition of the substance but do reflect its thermal properties.