Pressure on system and work done by the system

In summary, the insulating material in question has a large number of atoms with six degrees of freedom each. It initially occupies a small volume at a certain pressure, which is related to the volume by a constant. The question asks for the change in temperature when the pressure increases quickly and no heat enters or leaves the system, assuming that the potential energy per particle remains constant. The ideal gas law does not apply in this case as the material is a solid.
  • #1
leroyjenkens
616
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A certain insulating material has 5 x 1022 atoms, each having six degrees of freedom. It initially occupies a volume of 10-6 m3 at a pressure of 105 Pa. The pressure and volume are related by p(V - V0) = constant, where V0 = 0.94 x 10-6 m3

Homework Equations


[tex]W = -\int p\, dV[/tex]
PV = nRT
[tex]\bigtriangleup E = \bigtriangleup Q - \bigtriangleup W[/tex]
PiVi = PfVf

The Attempt at a Solution


[/B]
This one is confusing because it gives me one initial volume, and then gives me a V0 that's almost the same as the initial volume, so I don't know if I only use the V0 for that equation with the constant, or if I use that as the initial volume for something else. No idea why it gives me two different (but almost identical) initial volumes.
I solved for the constant, using the initial volume and the other initial volume for V, and then tried to use that constant and plugging in what I had in V in for V0 and solving for the V, which would be the final volume, and then plugging that into the limits of integration. That did nothing good.

I tried solving for the final volume, using PiVi = PfVf and then plugging that into my limits of integration, and multiplying P times ten. That didn't work.

I tried using PV = nRT and solving for T, but I don't know what to do with T. But the question gives me numbers of atoms, which is why I tried using the ideal gas law. Otherwise it would have been irrelevant information, as far as I can tell. It's an insulating material, so I guess it's not an ideal gas. It's probably a solid.
It gives me the degrees of freedom of the atoms. I have no idea how that's relevant.
 
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  • #2
I forgot to ask the question and I can't edit. But I figured out that part. The next part asks "Suppose that the potential energy per particle remains constant, and that the pressure increases sufficiently quickly that no heat enters or leaves the system during the process, ie, the process is adiabatic. By how much does the temperature of the insulator rise?"

I tried the ideal gas law, but it's not a gas, so I don't think it applies. I'm getting an answer with that equation that's close to the real answer; it has the same order of magnitude, but it's not close enough. I need something that relates pressure, temperature, moles, and volume, that can be relevant to a solid. I'm assuming it's a solid, and I don't think the ideal gas law applies to solids.
 

FAQ: Pressure on system and work done by the system

What is pressure on a system?

Pressure on a system is the force exerted per unit area on the boundaries of the system.

How is pressure calculated on a system?

Pressure can be calculated by dividing the force applied on the system by the area over which the force is applied.

What is the relationship between pressure and work done by the system?

The work done by a system is directly proportional to the pressure applied on the system. This means that as pressure increases, the work done by the system also increases.

Can pressure on a system be negative?

Yes, pressure on a system can be negative. This happens when the force applied on the system is in the opposite direction of the area over which it is applied.

How does pressure affect the behavior of a system?

Pressure can affect the behavior of a system in various ways. For example, it can cause a change in volume or temperature, or it can induce a phase change in the system.

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