How Do You Calculate Pressure from Number Density and RMS Speed in Argon Gas?

In summary, the conversation discusses finding the pressure inside a container of argon gas with a given number density and rms speed. The relevant equations are provided, but the attempt at a solution reveals a missing variable - the mass. The solution is suggested to be found by considering the concepts of one mole of gas, its volume, and Avogadro's law. The conversation then continues with clarifying questions and suggestions for consulting the periodic table and using the equations provided to find the missing variables.
  • #1
zellster87
15
0

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.
 
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  • #2
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.
 
  • #3
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.
 
  • #4
You have temperature - look at your equations. Still, looks to me like you should consult periodic table.
 
  • #5
What excatly is "number density" just a fancy way of saying volume seeing as the units are m^3?
 

FAQ: How Do You Calculate Pressure from Number Density and RMS Speed in Argon Gas?

What is number density and how is it related to pressure?

Number density refers to the number of particles per unit volume in a given substance. It is related to pressure through the ideal gas law, where pressure is directly proportional to the number density of gas molecules.

What is the difference between number density and mass density?

Number density is a measure of the number of particles in a substance, while mass density is a measure of the mass of that substance per unit volume. Number density is typically used for gases, while mass density is used for solids and liquids.

How does temperature affect number density and pressure?

As temperature increases, the average kinetic energy of particles also increases, causing them to move faster and take up more space. This leads to an increase in number density and pressure, as more particles are colliding with the walls of the container.

How is number density measured in a gas?

Number density in a gas can be measured by using the ideal gas law, where the number of gas molecules is divided by the volume of the container. It can also be measured indirectly by measuring other properties such as pressure and temperature.

Can number density and pressure be changed without changing the amount of gas?

Yes, number density and pressure can be changed by altering temperature and volume. As temperature increases, number density and pressure also increase. As volume decreases, number density and pressure increase as well.

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