Gas Definition and 1000 Threads

  1. J

    Centripetal Force & Gas Centrifuges

    Hi, I am studying circular motion at the moment and we were asked to go away and find an example of a device which has a very large centripetal acceleration. Initially I found a washing machine has up to about 300g but then I was looking at nuclear enrichment gas centrifuges which have huge...
  2. physea

    B Equations that describe ideal gas processes

    Hello! Is there a table to show the equations that describe ideal gas processes? For example, I know for isothermic, it's P1V1=P2V2, what about the others? Also, how are these derived? Is it from Q-W=dU? or PV=nRT? Any help? thanks!
  3. PKM

    How to find the thermal compressibility of a gas

    Homework Statement : [/B] A gas obeying the equation of state PV=RT undergoes a hypothetical reversible process PV^\frac{5}{3} e^\frac{-PV}{E_0} = c_1 Can we prove that the thermal compressibility of the gas undergoing this process tends to a constant value at very high temperature? Here, E_0...
  4. Al_Pa_Cone

    Steam and Gas Turbines - The Rankine Cycle

    <<Moved from another forum, thus no template filled out.>> I am having some trouble trying to relate a question given in my distance learning lessons to the equivelent question in my assignment. The assignement question is: 1(a) Superheated steam at a pressure of 40 bar and a temperature of...
  5. G

    Which Gas Compression Process Requires the Most Work?

    Homework Statement This is a conceptual question. An ideal gas is compressed to half its initial volume by means of several possible processes. Which of the following processes results in the most work done on the gas? a) isothermal b) adiabatic c) isobaric d) The work done is independent of...
  6. M

    B Finding the mass of gas ejected by a rocket

    I ran into this problem and need some guidance. Here's the question exactly as it appears in my sheet: "A 500 kg rocket is set for vertical take-off. If the exhaust speed is 1,000 m/s, the mass of gas ejected per second to supply the thrust needed to overcome the weight of the rocket is:"...
  7. Richie Smash

    Pressures of a gas in cm of mercury

    Homework Statement Hello, I will post a picture here of a question. It states, a column of air is trapped by 5cm of mercury as shown. What is the pressure in cm of mercury in the gas in each case? Homework Equations Pressure= h*g*rho The Attempt at a Solution I would use that equation but...
  8. Spinnor

    I Calabi-Yau manifold + ideal gas + point disturbance?

    Because it is a closed space, can it make sense to fill a Calabi_Yau manifold with an ideal gas and consider waves from a point disturbance? Would the Ricci-flat condition of Calabi-Yau manifolds have anything to say about possible sound waves? Thanks!
  9. Glurth

    Can a Self-Gravitating Gas Ball Simulate Stellar Formation Dynamics?

    I have a simulation I'm trying out (for fun). A self-gravitating ball of gas, in deep space. (The sim uses a fixed-time-step for each iteration.) I'd like to use Boyles Ideal gas law, the force of gravity, and energy as internal heat. (I don't want to touch enthalpy unless I don't realize...
  10. AbbeyC172

    Thermodynamics: Ideal Gas Law, find the temperature

    Homework Statement A 3-ft^3 container is filled with 2-lbm of oxygen at a pressure of 80 psia. What is the temperature of the oxygen?Homework Equations pV= nRT T= PV/nR R= 10.7316 psia x ft^3/ lbmol x R The Attempt at a Solution Hi everyone! So I understand how to use the Ideal Gas Law but my...
  11. H

    Find the work done on a monoatomic gas in this P-V diagram

    Homework Statement Homework Equations internal change = $$\frac{3}{2}n.R.(T2 - T1)$$ Work = P.ΔV The Attempt at a Solution 1) T2 = $$\frac {P2. V2 . T1 }{P1 . V1} = 1.2 * 10^3$$ 2) Q = Internal change = $$\frac{3}{2}n.R.(T2 - T1) $$ $$ = \frac{3}{2} * 1 *8.3*10^{-3}*(12*10^2 - 3*10^2) $$...
  12. D

    Calculating the resonant frequency of a gas cylinder

    I would like to make a bell out of a used compressed gas cylinder, but I would like to tune it to a specific note or frequency, e.g. A (440Hz). Can someone help with a formula to calculate this so I can cut it precisely?
  13. codcodo

    Why does the gas with the smallest molar mass have the highest pressure?

    Homework Statement If equal masses of Xenon, Argon and Neon are placed in separate flasks of equal volume and same temperature, which one of the following statements is correct: a) The pressure of Neon flask is greatest. b) The pressure of Argon flask is greatest. c) The pressure of Xenon flask...
  14. ElectricRay

    Relation between pressure and volume when heating a gas

    Hi all, A happy 2018 for all PF members. I have a question. I am trying to understand some basic principle of thermodynamics. My book tells me tge following: "Heating of a gas at a constant pressure uses more heat as when heating the same gas a constant volume" How do i interpret this? I...
  15. T

    Understanding Random Particle Motion in a Monoatomic Gas

    We consider a monoatomic gas in a closed box. A textbook says : Since the assumption is that the particles move in random directions, the average value of velocity squared along each direction must be same. Why the assumption is that the particles move in random directions implies that the...
  16. T

    Feynman's explanation of atomic collisions in gas

    In the first volume of his lectures' books, Feynman tries to mathematically describe that in a particular gas ( particular because in this case is the sum of 2 monoatomic gasses with different masses) as a result of the collisions beetween atoms it will be equally likely to find any pair moving...
  17. Pushoam

    Standard deviation of V_x of He gas

    Homework Statement Homework EquationsThe Attempt at a Solution ## \frac 1 2 m<v_x^2> =\frac 1 2 k_BT , \\ \sqrt{ <v_x^2>} = 556~ m/s ## So, I guess that the standard deviation should be less than rms speed. So, the option is (a) ## \left< ax + b \right> = a\left<x\right> + b...
  18. C

    Does electron gas in metals experience viscosity?

    Does electron gas in metals experience viscosity? Also, does highly charged plasma experience viscosity?
  19. T

    Calculate the Internal Energy of Monoatomic Gas

    Homework Statement Re-arranging the equations of potential (internal) energy in a monoatomic gas, i get this differential equation: \gamma (dV/V ) + (dP/P) = 0. where V is volume and P is pressure. I have to integrate it. Homework EquationsThe Attempt at a Solution I tried, but i wasnt able...
  20. A

    Piston with crankshaft: what is the temperature of gas entering the cylinder?

    Homework Statement Homework EquationsThe Attempt at a Solution e) I know the temperature is lower in the transparent container but how do you represent this
  21. Pushoam

    Free energy per unit volume of an ideal gas

    Homework Statement Homework EquationsThe Attempt at a Solution [/B] I am taking the free energy as the internal energy of the ideal gas. Then the average internal energy per unit volume is ## \frac { 3 nk_B T } {2 } ##. So, the correct option is (c). Is this correct?
  22. A

    I How long would it take for gas to leak out of a space box?

    I could not find an easy or believable source on this question on the internet. Anyway, if I had a box (volume V) in space full of gas (density N) and a hole suddenly appeared, how long would it take all of the air to completely leave the box out into space? I would assume the air would be at...
  23. S

    A Fermi and Bose gas in statistical mechanics

    In statistical mehcanics(pathria, 3rd edition), I have some questions for ideal fermi and bose gases. The textbook handles the approximation for z(=e^βµ) and nλ^3 (n=N/V, λ : thermal de Broglie wavelength). It considers the cases that z<<1, z~1, nλ^3~1,<<1,→0 and so on. In here, I am confused...
  24. B

    GAS numbers stamped on armatures -- what do they mean?

    I was wondering and this might be a stupid question... I have approx. 200+ armatures with a GAS number stamped on them Like "GAS 3237". There are probably 20 different numbers or so. Where can I find a list of what these numbers are or mean?
  25. M

    Gas adsorption for (BET) surface area of graphene oxide based thin films

    I am using a Micromeretics ASAP2020 machine. The sample is ~25mg of reduced graphene oxide based film. The problem is I am getting adsorption isotherms showing negative volumes of adsorbate (N2) entering the tube as P/P0 increases. The sample was degassed prior to testing at 250°C for 3...
  26. J

    I Fermi gas at the absolute zero T

    I'm currently studying Thermodynamic properties of a Fermi gas at the absolute zero temperature. I get how the internal energy, pressure... etc of the gas are derived. For example, in computing the internal energy, one sums up all the energy of states weighted by its average occupation...
  27. VSayantan

    Energy of a Gas in equilibrium with BB-radiation

    Homework Statement A closed, thermally-insulated box contains one mole of an ideal monatomic gas G in thermodynamic equilibrium with blackbody radiation B. The total internal energy of the system is ##U=U_{G}+U_{B}##, where ##U_{G}## and ##U_{B} (\propto T^4)## are the energies of the ideal gas...
  28. S

    What Must Remain Constant for W = pΔV to Apply?

    Homework Statement The work done W by an expanding gas is calculated using W = pΔV. What must remain constant for this equation to be used? a. The pressure of the expanding gas b. The pressure of the surroundings c. The temperature of the expanding gas d. The temperature of the surroundings e...
  29. Perodamh

    Which Gas Is More Compressible: Isothermal or Isentropic?

    Homework Statement Gas A at 125KPa (abs) is compressed isothermally and gas B at 100kPa(abs) is compressed isentropically (Y = 1.4). Which gas is more compressible?[/B]Homework Equations Compressibilty = 1/bulk's modulus Bulk's modulus = F/A/V/v or volume stress/volume strain The Attempt at...
  30. Pericles98

    Internal energy during the expansion of a gas?

    I have question regarding the (W = ∫Pdv) formula for the work done during the expansion of an ideal gas and the change in internal energy during the process. If we were to have a gas enclosed inside an insulated cylinder with a movable piston at one end with cross sectional area "a", I...
  31. M

    Ideal Gas Law Homework: Calculating Number Density and Spacing Between Molecules

    Homework Statement Consider an ideal gas at 25.0 degrees Celsius and with a pressure of 1.00 atm. a) What is the "number density" of the molecules, expressed as molecules per unit volume? (Cubic meter, cubic centimeter or liter) b) What is the typical spacing between molecules in the gas? Of...
  32. J

    What is the Ideal Gas Law for a Two-Bulb System with Varying Temperatures?

    1. Two equal glass bulbs are connected by a narrow tube and the whole is initially filled with a gas at a temperature of T0 and pressure of P0. Then, one of the bulbs is immersed in a bath at a temperature, T1 and the other in a bath at a different temperature, T2. Show that in this problem, the...
  33. Toby_phys

    Effusing gas onto the interior of an evacuated sphere

    Homework Statement A gas effuses into a vacuum though a small hole of area A. Show that if the particles effused into an evacuated sphere and the particles condensed where they collided that there would be a uniform coating. (7.6 of Blundell and Blundell) Homework Equations Angular...
  34. F

    Ionized Gas Cables: Can You Buy Them?

    Hi! Does it exist cables using ionized gas / plasma as the conductor available to buy? Thanks in advance!
  35. B

    Types of energy in a gas discharge tube

    I am reading about gas discharge tubes and can't work out the types of energy and energy conversion that occurs in a gas discharge tube. Initially before the tube is switched on you have an inert gas with kinetic energy. As soon as the tube is switched on there is an an electric field between...
  36. F

    CFD Modeling of Flue Gas Pollution Dispersion

    I've previously studied and used the k-epsilon turbulence model within Ansys to model water in a small stirred vessel. I am now interested in CFD models appropriate for modeling flue gas dispersion. I'd like to know: What additional considerations are required for modeling a gas as opposed to...
  37. patric44

    Discharging argon gas with a homemade tesla coil

    hello guys i made a small crude tesla coil ( slayer exiter ) and i tried it on multiple gas tubes that i had and i have been able to discharge neon , argon but i have a question : how strong the electric field needed to discharge argon gas ?
  38. H

    Ideal Gas Equation and Temperature change?

    During a thermodynamic process, the state variables of an ideal gas, measured in kPa, m3, and oC, varied in the following way: P2 = 2P1 V2 = 3V1 T2 = 8T1 What is the temperature increase of the gas, T2 −T1 ? I've been given an answer of 4780 and I'm not sure how to get there?
  39. T

    Phases of hydrocarbons in a compressed gas cylinder

    I'm currently in the process of selecting gas mixtures to calibrate a gas chromatograph. One of the gas mixtures I'm interested in has the following composition by percent volume: methane (CH4): 95% carbon dioxide (CO2): 1% butane (C4H10): 1% acetylene (C2H2): 1% nitrogen (N2): 2% The gas...
  40. J

    Internal energy of an ideal gas as a function of pressure?

    Assuming all gases in the combustion reaction of benzoic acid (C6H5COOH) behave ideally, what is the "exact" change in internal energy? The context in which this question is being asked is after a calorimetry experiment. For all the intents and purposes of calorimetry, the change in internal...
  41. H

    How to Calculate Ideal Gas State Properties Using Molecular Dynamics?

    Dear all, I want to calculate thermodynamical properties of my molecule which I am calculating its thermodynamical properties of non-ideal part using Molecular dynamics. I need ideal gas state total energy, Cp, and Cv in several different temperatures. I am using opt+freq at B3lyp/6-311++G(d,p)...
  42. Pushoam

    I Internal energy of any ideal gas

    The internal energy of monoatomic ideal gas is due to the kinetic energy of the molecules. Using Boltzmann Maxwell distribution, it is calculated that the kinetic energy due to translational motion of gas molecules of an ideal gas depends only on the temperature. In case of monoatomic gas, since...
  43. F

    Energy of an ideal gas given its multiplicity

    Question: The multiplicity of an ideal gas is given by g(U) = A.U3N/2, where U is the energy of the gas, A is a constant and N is the number of particles in the gas. Prove that the energy of the gas given a temperature T is U = (3/2).N.kb.T Attempts: My first thought was to...
  44. patrickmoloney

    Final Temperature of a monatomic gas

    Homework Statement The molar energy of a monatomic gas that obeys van der Waals' equation is given by E=\frac{3}{2}RT - \frac{a}{V} where V is the molar volume at temperature T and a is a constant. Initially, one mole of such a gas is at temperature T_1 and occupies a volume V_1. The gas is...
  45. T

    Relationship between the pressure gradient and mass flow of a gas

    Hi everyone, I would like to know how to calculate the diameter of a pipe when we know the desired mass flow, the gas type, and the pressure at both end. I have these requirements : Gas : O2 Molecular weight : 0.032 [kg / mol] Desired mass flow : 0.32 [kg / s] Pressure in the gas tank : p1 =...
  46. F

    Medical What Kind of Gas Could Be Leaking in My Bedroom?

    A few months ago there used to be some kind of gas leakage in the bedroom. Gas was almost odourless. I could detect the presence of gas only by aftereffects. They were : 1: I used to feel very sleepy. ( as if it was some anasthetic gas or chloroform) 2. Sometimes it used to feel like a breath...
  47. J

    Simple Gas Pressure Question - Combined Chambers Final Pressure

    Before anything, my apologies for offering such an elementary question about gas pressure. Any help would be appreciated. 1. Homework Statement There are two chambers. One is 100 L, containing air at a pressure of 200 kPa. The other, joined to it, is 10 L and contains air at a pressure of 20...
  48. A

    Gas analysis system design issue

    Hi all, maybe this is a silly question but I am a newbie in this particular design field. I'm working on a gas analysis system and I'm facing a mechanical design issue. The overall system is made of the electronic board (PCB) with a gas sensors array plus the signal conditioning electronics, a...
  49. S

    B Measuring the number of moles of a gas

    In the ideal gas law, the symbol n represents the number of moles of gas. My question is how, given a volume of a certain gas, one determines how many moles one has. My understanding is that a mole in this case denotes a quantity of particles. How does one determine how many moles one has...
  50. runningman19

    Adiabatic Compressor: Ideal Gas Temperature Change

    Homework Statement A mixture of hydrogen, carbon monoxide and carbon dioxide is being fed to a compressor at 2.0 bar and 25 C. The overall flow rate is 17.47 SCMS and its composition is 73.5 mol% H2, 13.7 mol% CO and the balance CO2 The compressor operates adiabatically and reversibly with a...
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