Which list shows the phases of matter in order from the greatest average kinetic energy to the least average kinetic energy per particle?
1. Gas, liquid, solid
2. Gas, solid, liquid
3. Solid, liquid, gas
4. Solid, gas, liquid
The correct answer is:
2. Gas, solid, liquid
In a gas, the particles have the greatest average kinetic energy because they are moving quickly and have more freedom of motion. In a solid, the particles have the least average kinetic energy because they are closely packed and vibrate in place. Liquid falls in between, with particles moving more freely than in a solid but less freely than in a gas.