Gas Definition and 1000 Threads

  1. D

    Entropy change of van der Waals gas expansion

    Homework Statement Consider ##n## moles of gas, initially confined within a volume ##V## and held at temperature ##T##. The gas is expanded to a total volume ##\alpha V##, where ##\alpha## is a constant, by a reversible isothermal expansion. Assume that the gas obeys the van der Waals equation...
  2. J

    What can be done with the excess FCC flue gas

    What can be done with the excess FCC flue gas from a fluid catalytic cracker
  3. D

    Is the Given Solution for S(T,V) of an Ideal Gas Accurate?

    Homework Statement Given: Ideal gas equations: Find S(T,V) for an ideal gas Homework Equations Ideal gas equations: \begin{array}{l} {\rm{}}\\ U = \frac{3}{2}N{k_B}{\left( {\frac{N}{V}} \right)^{2/3}}\exp \left[ {\frac{S}{{\left( {3/2} \right)N{k_B}}} - {s_0}} \right]{\rm{ }}\\ T = {\left(...
  4. B

    Explaining Brownian Motion & Gas Laws: Homework Solutions in 65 chars or less

    Homework Statement Can someone confirm if I answered correctly? Thanks for support and help! a) In the Brownian motion experiment, small particles of matter are seen moving randomly. Give an explanation for this motion. b) Boyle's Law is fundamental when discussing the gas laws. i) State...
  5. E

    Ideal Gas Law - Adding additional gas & additional question

    Hello, I know this has been fairly discussed to death, but I've had relative trouble finding a response that specifically addresses the n, in PV= nRT, the ideal gas law. Out of relatively common sense, by adding additional moles of gas, the pressure in the gas should increase as there are more...
  6. S

    Gas confusion -- cooling air in a pipe using venturis and mixing

    Hello everyone! I am new here. I have used this forum on and off through google searches in the past and learned a fair bit from the posts. This is the first time asking anything. The question is probably extremely simple but has been overrun in my head for a week! It is in regards to...
  7. J

    Exploring Industrial Gas Turbines: Heat Loss and Energy Output

    Hey guys Don't know if this is posted in the right category. doing an technical report on industrial gas turbines. but i am kind of lost. Does anyone have any input to what we can write about? I'm thinking of any problems with the turbines that we can write about. What heat loss and how much...
  8. Rumo

    Speed of sound in an isentropic ideal gas

    Homework Statement \rho_0, c_0 is the mean density, the mean speed of sound in the ideal gas. Is the following correct? c(\rho)=c_0\left(\frac{\rho}{\rho_0}\right)^{\frac{\kappa-1}{2}} Homework Equations p = const * \rho^\kappa, c=\sqrt{\frac{\partial p}{\partial \rho}} The Attempt at...
  9. AdityaDev

    Calculating volume occupied by 1 equivalent of gas

    Its given in my textbook that equivalence of gas = (volume of gas) / (Volume of 1 eq. gas at NTP) How do i calculate volume occupied by 1 equivalent of gas? Example: What would be the volume occupied by 1 eq. of CO2 (Its given 11.2l in my book) Is there a formula for this?
  10. K

    How much the gas has increased the speed of the plug?

    Homework Statement The cannon is made from V=30ml test tube completely closed with a plug (diameter d=1,5cm; length l=3cm; mass m=5g). Before closing the test tube, V'=1ml of water is poured into it. Room temperature is 20oC , pressure p=105 Pa , relative humidity is σ=20%. When the temperature...
  11. K

    How much the gas has increased the speed of the plug?

    Homework Statement The cannon is made from V=30ml test tube completely closed with a plug (diameter d=1,5cm; length l=3cm; mass m=5g). Before closing the test tube, V'=1ml of water is poured into it. Room temperature is 20oC , pressure p=105 Pa , relative humidity is σ=20%. When the temperature...
  12. A

    How to find atomicity of solid elements as can't apply the gas law

    we can use avogadro's law and gay lussacs law to find atomicity of gases but what about solid elements
  13. A

    Spectrum of a Gas from Thermal Motion

    Hi there, I'm trying to clear up some misconceptions I have about emission spectra from various substances. Most of the discussion about gases focusses on the line emission spectra from a hot, low density gas due to electron shell transitions. But I also know that any charges that are made to...
  14. terryds

    Kinetic Theory of Gas: F=-2mv/2L/V

    F = Δp/Δt http://www.sumoware.com/images/temp/xzhhjttxobbodxgr.png (Sorry for bad sketch.. hehe) In the kinetic-molecular theory of gas, the Δp is -2mv (since it's supposed to be elastic collision) But, why the Δt is 2L/V ?? I think it must be a very small time (since the impact is done in a...
  15. Mingsliced

    Thermodynamics: Gas pressure and change in volume

    Homework Statement Just want to check that I've used the correct method for this thermodynamics question I've been set. Any clarification would be greatly appreciated. So I have 0.5kg of gas held in a rigid container of volume 0.25m^3 at a temperature of 20°C. 20kJ of heat energy is required...
  16. AdityaDev

    Thermodynamics: sign convention

    In physics book, if work is done by the system, it is positive in my chemistry book, if work is done by the system, it is taken as negetive. when I asked my chemistry teacher, he said the sign convention is different in physics and chemistry. but why are they different?
  17. R

    Pressure in a container placed on a reduced area?

    Really simple question but it's been making me a little confused. Lets imagine we have a container (cubic with length of 1 meter) with a pressure of 1 Pascal and then an area inside the container of 1 mm^2 is chosen to measure the force on that area, what would the pressure be? 1 Pascal or...
  18. A

    Question about Ideal gas law and its application

    Homework Statement Estimate partial pressure of nitrogen in atm in a room where you are at this moment. Use an ideal gas approximation and assume that air is composed of only nitrogen and oxygen. Show how you arrive the final answer in detail. Homework Equations pv=RT, while p stands for...
  19. B

    What gases can be absorbed between 800 and 1000nm wavelength?

    Hi I was wondering if anyone could tell me what gasses are absorbed between 800 and 1000nm wavelength and weather there is a book that lists all the gas wavelengths that can be absorbed in this region Thanks bertopolis
  20. A

    How Does the Brayton Cycle Work in Gas Turbines?

    Hi I am new member ( mechanical engineer student ) , and the college just add a new course which is Turbo machinery , any way the teacher is new to the course & the quality of our teacher is not that good so , I was having a question and ask him but didnt get much from him so here I am ^^When...
  21. E

    How Is Time Factored Into the Derivation of the Ideal Gas Law?

    Here is a screenshot from a page from a textbook that explains how to derive the ideal gas law: In the third bold line, I don't understand how "time" in force = (change of momentum)/(time) is equal to 2x/u (the time it takes for the particle to travel to the opposite face and back again) -- I...
  22. P

    Change in internal Energy During Expansion of an Ideal Gas

    Homework Statement Derive an expression for the change in internal energy of 1 mol of an ideal gas for expansion from volume V_i to V_f under constant pressure of 1atm where \gamma = \frac{C_p}{C_v}=\frac{5}{3} Homework Equations \Delta U=\frac{3}{2}nR\Delta T PV=nRT The Attempt at a...
  23. H

    Chemistry What is the Mole Fraction of Each Gas in the Mixture?

    Homework Statement At 1 atm and 0° C, a 5.04 L mixture of methane (CH4) and propane(C3H8) was burned producing 20.9 g of CO2. Assume complete combustion. 1. How many moles total of methane and propane were present before combustion? 2. How many moles of carbon dioxide were present after the...
  24. S

    Specific Heat at constant pressure for photon gas

    Homework Statement A blackbody photon gas is contained within an evacuated cavity (V = 0.01 m^3). Calculate C_p for the photon gas at T = 1000K Homework Equations C_p - C_v = T(\frac{\partial S} {\partial V}) (\frac{\partial V}{\partial T}) C_v = T(\frac{\partial S} {\partial T}) S =...
  25. A

    Applying the ideal gas law in the Earth's atmosphere

    Hi there, I'm considering how the ideal gas law applies in practice in our planet's atmosphere. In particular, I'm considering this form of the law: P = ρRT (1) where P is pressure, ρ is density, R is the gas constant and T is the temperature. I also know that, to a good approximation, the...
  26. HelloCthulhu

    Electrolysis System Work and Real Gas Law

    Greetings Everyone! I read a very good thread regarding how Ideal Gas Law is used to calculate system work for the electrolysis of water: W = PΔV = (101.3 x 103 Pa)(1.5 moles)(-22.4 x 10-3 m3/mol)(298K/273K) = -3715 J https://www.physicsforums.com/threads/work-of-electrolysis-of-water.756240/...
  27. J

    Calculating Volume of Escaped Air Bubble Using Ideal Gas Law | Homework Question

    Homework Statement An air bubble of volume 3.0x10-5m3 escapes from a divers equipment at a depth of 45m where the water temperatures is 5 degrees C. What is its volume as it reaches the surface, where the temperature is 12 degrees C? Atmospheric pressure = 101kPa, density of sea water =...
  28. W

    Work done by monoatomic ideal gas

    Homework Statement The volume of 30.0 moles of a monoatomic ideal gas is reduced at a uniform rate from 0.616m3 to 0.308m3 in 2h. Its temperature is increased at a uniform rate from 27.0◦C to 450◦C. The gas passes through thermodynamic equilibrium states throughout. (a) Write down explicitly...
  29. M

    Gas in a semi permeable membrane - one for the gas experts

    I believe I know the answer to this question; I need an expert to verify it for me. I work for a company that makes latex balloons. The people that have been here for a long time insist that if one is putting a small (5" balloon) filled with helium inside a larger (30") balloon then one must...
  30. T

    Learning About Reciprocating Compressors for Oil & Gas Engineers

    Dear All, I am a mechanical engineer who has recently started working in the oil& gas industry (compression). I would appreciate if someone can guide me to where can I learn about reciprocating compressors. Much appreciated.
  31. C

    Calculating Kp for gas mixture from picture

    Homework Statement A chemical reaction is described by the equation N2O4 <> 2NO2. The pressure equilibrium constant for the given reaction is equal to 8 Pa. Which picture describes the equilibrium? (Please, see the attached file!). [/B]Homework Equations N2O4 <> 2NO2[/B]The Attempt at a...
  32. I

    Air Pressure Reduction as a Function of Height Above Sea Level

    Homework Statement Let ##h## be the height above sea level. Show that the reduction in air pressure ##dp## as a function of ##dh## is given by ##\frac{dp}{p} = -\frac{Mg}{RT}dh##. Where ##M## is the molar mass of air and ##T## the temperature at height ##h##. 2. Solution This problem got a...
  33. F

    How to Prove (∂U/∂V)P = TCV/V for a Perfect Gas?

    Hi! I need to prove that: (∂U/∂V)P = TCV/V For a perfect gas. But I don't know start. Can you help me please?
  34. R

    Deviation of a gas from ideal gas behaviour

    Hi all, I have a question from a tutorial sheet that I'm stuck with. The question is Estimate the pressure at which a gas of argon atoms, at a temperature of 300 K, will begin to show deviations from the ideal gas behaviour due to the finite size of the atoms. Answer: Of order 10^9 Pa. So I...
  35. M

    Chlorine gas, Nitrogen and Sodium Hydroxide

    What combination of these might produce a brown solid? For talking's sake...
  36. f95toli

    What happens when a pressurized gas cylinder falls over?

    This is health&safety related question that came out of a discussion I had with a friend. I sometimes keep a large (L sized) helium cylinder in my lab. It is pressurized to 200 Bar and equipped with a standard regulator. Now, the question is what would happen if it fell over and the...
  37. Seydlitz

    Deriving Ideal Gas using Molecular Flux Equation

    So basically I was wondering whether it's possible to get the expression of ideal gas using molecular flux equation which is ##\phi = \frac{1}{4}\bar{v}n##. The derivation should be straightforward. I need to get the expression of pressure. Because the flux by definition already gives the rate...
  38. N

    Did I Convert 5 Pounds of Nitroglycerin to Moles Correctly?

    Homework Statement 5 lbs of nitroglycerin detonates. What is the total volume of the gases produced? Homework Equations PV=nRT The Attempt at a Solution I used the balance chemical equation of the decomposition of nitroglycerin and used stoichiometry to find the number of moles of nitrogen...
  39. N

    How Many Liters of CO2 Does Eating a Giant Gummy Bear Produce?

    Homework Statement (problem won't be word for word, because much of the info. is to throw people off); This large gummy bear, which contains 51 servings and each serving contains 29 grams of carbs. Assuming all the carbs are glucose, how many liters of CO2 would eating this gummy bear cause...
  40. N

    Calculating Pressure in the Stomach after Taking Tums

    Homework Statement Tums react in your stomach to produce a gas. The average adult stomach expand to one liter when full. Calculate the pressure in the average adult stomach after taking 2 Tums. Homework Equations Since its asking for pressure, and the volume is given perhaps PV=nRT should be...
  41. J

    How does a fuel gas system operate

    Any of you know how a fuel gas system operates
  42. Z

    Ideal gas law combined with vapor pressure

    I am working on a DIY project and want to understand the system/mathematical model of a traditional steam espresso machine. How I have started to think about the problem is a closed container with liquid and gas. At room temperature I know the vapor pressure of the water. As I increase the...
  43. L

    Entropy Change for an Ideal Gas

    Homework Statement 10 moles of an ideal gas Cv = 20.8 J/mol at T0 = 300 K and P0 =0.3 MPa occupy the left half of an insulated vessel. At time t=0 a 1 kW electrical heating element is turned on. after 30 s, the partition dividing the vessel ruptures and the heating element is turned off...
  44. Robin04

    How can the radiation of gases be detected?

    I'm curious about that do gases emit infrared radiation the same way as solid bodies do? If yes, how can it be detected like an infrared camera does?
  45. S

    Work done isothermal, adiabatic ideal gas

    Problem statement, work done, and relevant equations: One mole of ideal gas is initially at 1 atm and has a volume of 5L. a) Calculate the work done on the gas during an isothermal, reversible compression to a volume of 2L. ##W_isothermal = - \int_{v_i}^{v_f} p dv = - \int_{v_I}^{v_f}...
  46. P

    Probability distribution for a rotating gas

    Homework Statement A cylinder contains an ideal gas and rotates at angular speed w. Find the probability that a molecule is at radial position r from the axis of the cylinder. Homework Equations Boltzmann distribution, P(E)∝Ω(E)exp(-E/kT) where Ω(E) describes the degeneracy of the energy level...
  47. B

    Calculating Kinetic Energy of a Gas at Different Temperatures

    Homework Statement A stationary gas has a kinetic energy of 500 J at 30 C. What is its kinetic energy at 60 C? Homework Equations KE = 3/2 RT The Attempt at a Solution I first converted T to Kelvin = 333K. I substituted all the values into find KE but my answer is around 40K, which is not...
  48. predaylight

    De Broglie wavelength and ideal gas entropy derivation

    When the ideal gas entropy is derived, we consider N atoms in a box of volume=Lx*Ly*Lz. Then, we make the assumption that Lx,Ly,Lz >>de Broglie wavelength of atoms. I am not sure why we need to make this assumption? Thanks!
  49. B

    What Changes During Free Adiabatic Expansion of a Real Gas?

    Homework Statement Which of the following changes during the free adiabatic expansion of a real gas? (I) internal energy (II) temperature (III) pressure Homework Equations PV=nRT; ΔU= q + w The Attempt at a Solution For ideal gases under adiabatic conditions, we know that there is no heat...
  50. Kaleem Ullah

    How to Calculate Gas Concentration in a Chamber Without Sensors?

    How can we find the gas concentration in a chamber without using a sensor i mean by calculation suppose a mixture of gas ammonia 10% and CO2 90% flow to the gas chamber how we can find that concentration of gas in the chamber?
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