Thermodynamics gas work done question

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Homework Help Overview

The discussion revolves around a thermodynamics problem involving a non-ideal gas. The problem presents a relationship between pressure, volume, and temperature, and asks for the work done by the gas as its temperature changes while pressure remains constant.

Discussion Character

  • Exploratory, Conceptual clarification, Problem interpretation

Approaches and Questions Raised

  • The original poster attempts to relate the work done by the gas to various equations but expresses confusion about the applicability of those equations to a non-ideal gas. Some participants suggest focusing on the relationship between volume and temperature under constant pressure, while others inquire about the implications of holding pressure constant.

Discussion Status

The discussion is ongoing, with participants exploring different interpretations of the problem. Some guidance has been offered regarding the integration of pressure and volume, but there is no explicit consensus on the approach to take.

Contextual Notes

Participants are navigating the complexities of non-ideal gas behavior and the implications of constant pressure on volume changes. There is a noted lack of clarity regarding the equations applicable to this specific scenario.

Norton
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Homework Statement


In the temperature range 310K and 330K the pressure of a non ideal gas is related to volume V and temperature T by P=(24.9 J/K) T/V− (0.00662 J/K^2)T^2/V. How much work is done by the gas if it's temperature is raised from 310K to 320K whilst pressure held constant?


Homework Equations


P=(24.9 J/K) T/V− (0.00662 J/K^2)T^2/V


The Attempt at a Solution


I'm quite stumped on this one, initially I thought maybe something to do with W=NkT(ln)Vf/Vi, but I was wrong since the temperature has changed. I also tried using Q=n(Cp)(deltaT), but it is for an ideal gas and the question is talking about a non ideal gas. If someone could just give me a bit of a hand showing me the equations I should be using that would be great, since that is where I think I am falling down at the moment.

Thanks
 
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Norton said:

Homework Statement


In the temperature range 310K and 330K the pressure of a non ideal gas is related to volume V and temperature T by P=(24.9 J/K) T/V− (0.00662 J/K^2)T^2/V. How much work is done by the gas if it's temperature is raised from 310K to 320K whilst pressure held constant?
The expression for V is in the form:

[tex]V = aT/P + bT^2/P[/tex]

You want to find [itex]\int PdV[/itex]. To do that, you need to find dV.

What is dV/dT if P is constant?

AM
 
Sorry I'm still lost. I understand the expression for V, but what happens when P is constant?
 
Norton said:
Sorry I'm still lost. I understand the expression for V, but what happens when P is constant?
It enables you to calculate work easily: [itex]\int Pdv = P \int dV[/itex].

AM
 

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