The average kinetic energy of the molecules in a gas sample depends only on the temperature, T. However, given the same kinetic energies, a lighter molecule will move faster than a heavier molecule, as shown in the equation forms speed 3RT mms speed where R = 8.314 3/(mol-K) and .M is molar mass in kilograms per mole. Note that a joule is the same as a kilogram-meter squared per second squared (kg-m/s2). What is the rms speed of CI, molecules at 455 K? rms speed: m/s What is the rms speed of He atoms at 455 K? rms speed: m/s