gas

  1. T

    How would you determine the volume of a cylinder with fixed volume given air pressure measurements over time and the ability to add more air.

    In the system I am looking at: We have 3 scuba tanks of constant volumes V1, V2, V3. Any of these fixed volume tanks can be attached to an air compressor but this is done in secret so you do not know which tank was attached. The goal is to determine which of the fixed volume tank has been...
  2. K

    Ideal gas vs. real gas calulations

    Dear Physicists, I would ask about the confirmation of my concept, because at work I don't have any thermodynamic specialist to consult it with. I am not a physicist and probably this problem will be trivial for you, but I will appreciate any comments. My project is to recover greenhouse...
  3. L

    Temperature function of a gas derivation help

    I cant quite figure out how the so-called temperature function of a gas equation is derived from equations 1-4 in the attachment(from Planck's treatise on thermodynamics). Anything that helps me understand how this is arrived at would d be much appreciated!
  4. P

    Pressurized gas container gets opened

    Hi guys! So the question that I am working through is about a container of gas that is closed then opened to the atmosphere. I am given the pressure of the container (110500 pa), the mass of the air in the container (4 grams of air). I am also told the once the container is opened (which is...
  5. R

    Heat transfer between flue gas and feed water?

    I need to determine the temperature of flue gas in a fire tube boiler. Tube inlet gas temperature, T1 = 1045 deg.C Saturation water temperature, tsat = 186 deg.C Flue gas temperature, t2 = ? 2 equations to be used here: Q = U.A.LMTD -------------(1) Qg = Mg.Cg.(T1 - T2) ------(2)...
  6. M

    Gas flow direction in chamber with holes

    Hello, I built a chamber for oxidation testing and I was trying to come up with a way to direct the flow preferentially to the specimens. A top view of the chamber: The chamber is inside a big furnace under vacuum: there is one entry for air on the right (blue) and two Exits on the...
  7. P

    No smoking sign at gas station

    Here's a cool question I thunk up. At Lisa's Fuel and Eats gas station the there is a no smoking sign. A man is driving in his car minding his own having a smoke realizes he need to get gas. He stops at Lisa's, gets out of the car with smoke in hand and starts filling up his car with gas...
  8. J

    Cylindrical containing a neutral ionized gas

    In a cylindrical container of radius R and height h \ll R, with long axis \hat{z} , in the presence of gravity acceleration \vec{g}=−g \vec{z} is contained a neutral ionized gas, whose ions can be described as material points with electric charge q>0 and mass M (heavy positive ions) and...
  9. S

    Thermodynamics - Temperature change of argon gas

    the temperature of n = 19 mol of argon gas is increased from T1 = 21 oC by Q = 4.4 kJ heat transfer, while the gas pressure is kept constant. What is the new gas temperature in Celsius degrees? Q=n*Cv*change in Temp as its a monoatomic gas I think this means that the equation is just...
  10. D

    Help needed for thermo efficiency

    Still working on my physics nearly done, I need help with the calculations of heat transfer in a room of 10x10x5high in metres, with the use of heat pump, and gas furnace. The purpose of the calculation is to determine thermal efficiency ..plus energy required to heat the room from 0 to 25 C, I...
  11. G

    Ideal gas state calculation

    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)...
  12. T

    Physical significance of PV of a gas mass

    Hi This might seem to be a simple question off the bat, but I would like your comments on it. When pressure of a gas is P and specific volume is v what is the physical meaning of Pv? I tried to interpret it as the "Compressive Energy" of the gas mass. Assume the air mass is at the volume...
  13. C

    A-Level ideal gas law problem?

    A fixed mass of nitrogen gas is originally held in a 2 dm^3 volume container at a pressure of 101 kPa and a temperature 15 degrees celsius. The gas is compressed slowly within the container under isothermal conditions until it reaches a new volume of 1 dm^3. It is then heated at a...
  14. S

    Ideal Gas Equation - Problem regarding mass

    Hi people, I needed some assistance with this problem I came across that involved the use of the ideal gas equation. Q. A gas cylinder has a volume of 20 litres (20*10^3 m^3). It contains air at a temperature of 17 degrees Celsius and an excess pressure of 3.0*10^5 Pa above the atmospheric...
  15. C

    Gas concentration by ppm for an increase in pressure

    Air compressed to 24 Mpa with a final Co2 concentration of 400ppm is increased in pressure to 29 Mpa from atmosphere at a initial Co2 concentration of 300 ppm, what is the final Co2 concentration in ppm?
  16. S

    Simple gas effusion question

    I can't seem to work out question 107. I can do 106 and 108. I keep getting B for 108 but the answer is A Can you see the link, if not here it is http://m.imgur.com/a/TQ8MS sorry
  17. A

    Why gas clouds collapse if the forces are conservative?

    Hello all, You all have always kindly helped me as I remember questions I have accumulated since high school days, and have never been answered. Eventually I gave up and forgot them, but as I grow old for some odd reason these things pop back up in my mind, like old ghosts from 35 years ago. So...
  18. H

    Question about Entropy of a VDW gas

    Problem: There is a piston that is filled with 4 mol of a vdw gas and is locked in place at 1 atm and 50L. It is then released and compresses the gas to 4L. The piston is in a large bath so the temperature remains constant. Find the entropy of the universe for this. a=4 L^2 atm mol^-2 b=0.03 L...
  19. L

    Changing state of an ideal gas

    Hello everyone, I've been given following question: "An ideal gas is enclosed in a container at state (p1,V1,T1). It is desired to change the state of the gas to (2p1,V1,2T1). This has to be done by only two processes (i.e isothermal followed by isobaric) the processes can't be of the same...
  20. S

    How to calculate the change in entropy for a non ideal gas?

    Im looking at using what we call Tds relations Tds = du+PdV and apparently integrating this will get the change in entropy. I dont know how to do this and how it would work? Where do you substitute in values for pressure, temp etc. Could someone please shed some light on this? I also...