Perfect gas Definition and 24 Threads

In physics and engineering, a perfect gas is a theoretical gas model that differs from real gases in specific ways that makes certain calculations easier to handle. In all perfect gas models, intermolecular forces are neglected. This means that one can neglect many complications that may arise from the Van der Waals forces. All perfect gas models are ideal gas models in the sense that they all follow the ideal gas equation of state. However, the idea of a perfect gas model is often invoked as a combination of the ideal gas equation of state with specific additional assumptions regarding the variation (or nonvariation) of the heat capacity with temperature.

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  1. L

    Efficiency of Stirling Cycle - Is it the same as the Carnot Engine?

    TL;DR Summary: Efficiency Of Stirling Cycle - Is it the same as the Carnot Engine? Why is my described engine not the same as Stirling engine? Ok, the problem I was given is this: One mole of a perfect gas goes through a quasistatic cycle consisting of the following four stages: 1. isothermal...
  2. Hak

    B Applying Bernoulli's equation to problems involving a perfect gas

    I would like to know the opinions of experienced forum users regarding an issue that seems to happen often in problems: namely, applying Bernoulli's equation to perfect gas. Is it permissible to do so, even if only to find reasonable estimates? Two examples I found out might be: - The problem...
  3. eneacasucci

    I Variation of air temperature with altitude

    Considering the approximation of perfect gas, I don't understand why at higher altitude the temperature is lower. Intuitively it is clear to me, but I do not understand the kind of transformation that takes place; the gas is free to expand and the pressure too is not constant, since it decreases...
  4. H

    I Exploring Work Done in Quasi-Static & Non Quasi-Static Expansion

    I'm wondering what's the difference between work done on quasi-static and non quasi-static expansion. In a quasi-static process, the gas inside the system must do a work to "extend". However, in a non quasi-static process, where the gas inside the system doesn't move fast enough to "push" the...
  5. L

    Engineering System Constants for Perfect Gas

    Q) I have to explain the relationships between system constants for a perfect gas. Hi can somebody explain this to me. I am kind of confused what this means and where to start and what to do. Also not 100% sure what a perfect gas is.
  6. L

    Engineering Differences between an Ideal gas and a perfect gas?

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  7. greg_rack

    Maxwell-Boltzmann distribution for the simulation of a perfect gas

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  8. Death eater

    I What is the difference between a perfect gas and an ideal gas?

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  9. Aleoa

    I Perfect gas in a box with a piston

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  10. C

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    Two different gasses (Helium and Cripton) are mixed up. We can assume the compound behaves as a perfect gas only if the atoms of He and Kr have the same average value of: Mass Momentum Velocity Kinetic energy Which one is correct? I can't figure it out.
  11. S

    Why is 2L used as the distance in the derivation of 1/3nMc^2 = nRT?

    In the derivation the first step used F=Δmv/t and for t, they used t=2L/v where L is the distance between one end to the other end of the wall. But I don't understand why we use 2L as the distance. Isn't the force exerted by that molecule only for the very short period where the molecule is in...
  12. S

    What does the maximum work of a reversible expansion mean?

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  13. S

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  14. E

    What Is the Work Done by a Perfect Gas During Compression?

    Homework Statement An ideal gas at initial temperature T1 and pressure P1 is compressed by a piston to half its original volume. The temperature is varied so that the relation P=AV always holds and A is a constant. What is the work done n the gas in terms of n (moles of gas) R (gas constant)...
  15. I

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  16. T

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  17. T

    Determine the unknown property of a perfect gas

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  18. T

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  19. R

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    Homework Statement Calculate the percent difference of P2/P1, T2/T1, and ρ2/ρ1 between the CPG assumption and the thermal-chemical equilibrium assumption. Which percent difference is the lowest and what could be the possible reason? U1=4000 m/s Altitude=60 km R=8314 N m/(kmol K) P1=21.96 Pa...
  20. P

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  21. S

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  22. S

    Gravity's Impact on Perfect Gas Flow in Constant-Area Duct

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  23. A

    Entropy of a perfect gas at 0 kelvin

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  24. B

    Solving the Perfect Gas Equation for Volume at Sea Level and 2000m

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