# Help needed calculating speed distribution

1. Jan 17, 2012

### dq/dt58

1. The problem statement, all variables and given/known data
I have a sealed container of volume v = x m^3, which holds a sample of y x 10^24 atoms of He gas in equilibrium.
The distribution of speeds of the atoms is peaking at 110 m s^-1.

How do I calculate the temperature and pressure of the He gas?
Which equations would I use to calculate the average kinetic energy of the atoms?

2. Relevant equations
I don't know where to start.

3. The attempt at a solution
This is what I need help with.

2. Jan 17, 2012

### Spinnor

3. Jan 18, 2012

### dq/dt58

Thanks Spinnor,

I had already accessed these, but I still can't figure it out. I have a whole host of equations (Boltzmann, Boyle, etc...) and I fully understand the concepts involved, but when I wrote "I don't know where to start", I simply meant, I ACTUALLY don't know HOW to start.
I have the volume of the container (0.10 m^3), the number of helium atoms (3.0 x 10^24) at equilibrium and the peak of the speed distribution of these atoms (1100 m s^-1).

I have P = N * (m<vx^2. ÷ L^3)
I know Helium is a monatomic gas and that the mass of one helium atom is 4.0 amu.

As it is in equilibrium, there are no changes (Δ), so I need to find the value of the temperature FIRST in order to calculate both the pressure, and I need the pressure and the temperature to calculate the KEav of the helium atoms. From this I need to establish the position of the maximum in the energy distribution.

So everything in this question comes from where to start. Once I get going I have no trouble, because it's only calculations. I therefore need help in "entering" the problem. That's my problem.
I can't for the life of me and with application find any examples in my own textbooks or other physics books that might give me a template to work from for that "Aaaah!" moment of recognition.

If you have any ideas to put me on the right path, I'd be grateful.