Which state of matter has the highest energy level?

The state of matter with the highest energy level is gas. In the gaseous state, molecules have a significant amount of kinetic energy, which allows them to move freely and rapidly in all directions. This high energy level is a result of the large amounts of space between the molecules, enabling them to overcome intermolecular forces effectively, leading to greater molecular motion.

As compared to solids, where molecules are closely packed and vibrate in fixed positions, or liquids, where molecules are still close but can slide past one another, gases possess much higher energy. Additionally, plasma, while it can also be considered a state with high energy, is formed at extremely high temperatures when gas is ionized, resulting in a significant release of energy and hence is often seen in stars, including the sun.

Understanding the energy levels of different states of matter is crucial in HVAC refrigerant selection and system performance, particularly when considering phase changes that are fundamental to refrigeration cycles.