Problem 12.01 Root-Mean-Square Speed (a) What is the RMS speed of nitrogen at 20 C? Answer in units of m/s. Nitrogen gas: m = 28 amu (atomic mass units). (b) What is the RMS speed of helium at 20 C? Answer in units of m/s. Helium gas: m = 4 amu. Problem 12.02 Translational Kinetic Energy (a) What is the total translational kinetic energy of 2.0 moles of air outside (assuming an outside temperature of -10.C)? (b) What is the speed of individual molecules? mair = 28.97 g/mol