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

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

Answer: (C)

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) and is given by the formula: \(KE_{avg} = \frac{3}{2} k_B T\), where \(k_B\) is the Boltzmann constant and \(T\) is the temperature.
2. Understand that the phase of matter (solid, liquid, gas, plasma) depends on the energy and movement of particles. In solids, particles vibrate in fixed positions with relatively low kinetic energy. In liquids, particles move more freely but are still close together, so they have higher kinetic energy than solids.
3. Recognize that gases have particles that move rapidly and are far apart, resulting in higher average kinetic energy compared to solids and liquids at the same temperature.
4. Consider plasma, which is an ionized gas with extremely high energy particles. Plasma generally has even greater average kinetic energy than gases because the particles are ionized and move very fast.
5. Conclude that among the given options, plasma has the greatest average kinetic energy, followed by gas, liquid, and solid. However, if plasma is not considered or is not the focus, gas has the greatest average kinetic energy among the common phases of matter.