Number Density and pressure

[zellster87]

Homework Statement

The number density in a container of argon gas is 2.00 X 10^25. The atoms are moving with an rms speed of 455 m/s. What is the pressure inside the container?

Homework Equations

V rms = sqrt( (3)(k)(T) / m)

P = F/A = (1/3)(N/V)(m)(v^2 rms)

The Attempt at a Solution

I have tried manipulating all the equations to somehow find the pressure, but have been unsuccessful. I seem to have all the variables except the mass. So i assume i need to get the mass somehow, any ideas?

Thanks.

 

[rl.bhat]

What is one mole of gas? What is its volume? What is Avogadro's law?
Answers to these questions will lead to the mass of the argon.

 

[zellster87]

Is the moles the number density divided by Avogadro's number? And how do i get the volume? I can't use the ideal gas law since i don't have temperature.

 

[Borek]

You have temperature - look at your equations. Still, looks to me like you should consult periodic table.

 

[talaroue]

What excatly is "number density" just a fancy way of saying volume seeing as the units are m^3?