Kaplan Nursing Entrance Practice Exam

Which state of matter has the highest average translational kinetic energy?

1. Solid

2. Liquid

3. Gas

4. Plasma

The correct answer is: Gas

The state of matter with the highest average translational kinetic energy is gas. In gases, the particles are far apart and move freely at high speeds in all directions. This high level of energy is a direct result of the relatively weak intermolecular forces present in gases compared to solids and liquids. As the gas particles collide with one another and the walls of their container, they exhibit a significant amount of movement, which is indicative of their translational kinetic energy. While plasma also has a high average kinetic energy, it is primarily characterized by the presence of ionized particles and does not necessarily have higher translational kinetic energy than gases under standard conditions. Solids, on the other hand, have more tightly packed particles that vibrate in place, resulting in lower translational kinetic energy. And liquids, while having more freedom of movement than solids, still have stronger intermolecular forces than gases, leading to lower average kinetic energy than that found in gases. Therefore, the gas phase clearly exhibits the greatest average translational kinetic energy among the states of matter.