Helium is used to fill a balloon of diameter 44 cm at 22 degrees C and 0.9 atm.
The mass of a helium atom is 4.0026 u, the conversion factor from u to kg is 1.66 x 10^-27 kg/u, the conversion factor from atm to Pa is 1.013 X 10^5 Pa/atm, the universal gas constant is 8.31451 J/K mol, the Boltzmann's constant is 1.38066 x 10^-23 J/K.
What is the average speed (ie, the root mean square speed) of each Helium atom? Answer in units of m/s.
Vrms = sqrt(3RT/M)
The Attempt at a Solution
I think my problem is with finding the mass. I did this:
4.0026 x 1.66 x 10^-27 = 6.644316 x 10^-27
T = 22C = 295K
R = 8.31451
Sqrt( (3 x 8.31451 x 295)/6.644316 x 10^-27)
1.0523612 x 10^15
That is wrong. Any help on where I messed up? Thanks.