a) what is the rms speed of four hydrogen molecules with the speeds of 890, 755, 902, 866m/s?
Ans : 855m/s
My problem is part b)
b) at what temperature would these hydrogen molecules be?
( Mass of H atom = 1.67 x 10^(-27) kg )
Now, in 1/2m<c^2> = (3/2)kt, should I use the mass for only 1 hydrogen atom, or mass of 2 hydrogen atoms, or the mass for all 8 atoms in 4 molecules?
the answer in the solution book is 29K which only comes if I use mass for only one atom. ( They did not show any working )
The confusion arises when I tried the following question:
Q. Estimate the rms speed of the molecules of air in this room.
The answer given in the solution book :
Estimate of 20 °C (T = 293 K); assume all molecules are dinitrogen, so m = 4.676 × 10^(–26) kg; gives rms = 509m/s.
( They have used mass of two nitrogen atoms here )
Please help :-)