Thermodynamics- rms translational kinetic energy

[yaykey428]

Homework Statement

A container having a volume of 1m^3 holds 5 moles of helium gas at 50C. If the helium behaves like an ideal gas, the rms translational kinetic energy is?

Homework Equations

Total E= 3/2 nRT

The Attempt at a Solution

I tried solving this question using this equation, but I did not get the right answer.
The correct answer is 6.7 x 10^-21 J

 

[ehild]

Welcome to PF!

Please, show your work. ehild

 

[yaykey428]

Total Ek= 3/2 nRT
= 3/2 x 5 x 8.314 x 323
= 20140.7J, but this answer is wrong

 

[vela]

The problem is asking for the energy per atom.