What is the average kinetic energy of gas molecules at a tem

What is the average kinetic energy of gas molecules at a temperature of 263 K?  If the molecules have a mole mass of 40.0 g, what is their rms velocity?

Solution

The formula is KE = 3/2kT

where T is the Kelvin temperature=263K and k is boltzmann constant = 1.38x10^-23

so, KE = (3/2)x1.38x10^-23x263 = 5.444 × 10²¹ J

rms velocity = sqrt(3RT/m) = sqrt(3x8.314x263/40x10^-3) = 404.96 m/s