According to the kinetic molecular theory, which state of matter has particles with the greatest average kinetic energy?

• A. Solid
• B. Gas
• C. Plasma
• D. Liquid

Answer: (B)

Verified step by step guidance

1. Recall that the kinetic molecular theory relates the temperature of a substance to the average kinetic energy of its particles. The average kinetic energy (KE) of particles is directly proportional to the absolute temperature (in Kelvin) of the substance, given by the formula: \(\text{KE}_{\text{avg}} = \frac{3}{2} k_B T\), where \(k_B\) is the Boltzmann constant and \(T\) is the temperature.
2. Understand that the states of matter (solid, liquid, gas, plasma) differ primarily in the energy and movement of their particles. Generally, as you move from solid to plasma, the particles have increasing energy and freedom of movement.
3. Compare the typical temperatures and particle energies of each state: solids have particles vibrating in fixed positions, liquids have particles moving more freely but still close together, gases have particles moving rapidly and far apart, and plasma consists of highly energized, ionized particles.
4. Since plasma is an ionized gas at very high temperatures, its particles have even greater kinetic energy than those in a gas. Therefore, plasma particles have the greatest average kinetic energy among the states of matter.
5. Conclude that according to the kinetic molecular theory, the state of matter with the greatest average kinetic energy is plasma, followed by gas, liquid, and solid in decreasing order.