Gas Definition and 1000 Threads

Homework Statement Two moles of an ideal gas undergo a reversible isothermal expansion from 3.37×10−2m3 to 4.29×10−2m3 at a temperature of 29.6 ∘C. What is the change in entropy ΔS of the gas? Homework Equations pV=nRT The Attempt at a Solution W=∫V2V1pdV, I don't know how to use this...

Homework Statement If number of molecules in a closed container increases and it is kept at a constant tempurature, what happens to the pressure? I was confused because I thought if you add molecules the temputature would go up so keeping temputature a constant would have no affect on the...

In my book it is mentioned that piston effort along the line of stroke=(Force due to gas pressure)+(Inertia force) why we have to consider inertia force when it is a imaginary force which is considered only during non inertial frame? why we don't equate piston effort with gas force simple...

Homework Statement [/B] You are asked to calculate changes in internal energy, entropy, heat transferred and work done for each of the following process. Also you are asked to calculate "the latent heat for the isotherm in the figure". We know the a and b parameters which characterize the VdW...

Dear PF Forum, A: 1 mole O2 is roughly 32 grams? 1 mole ozone is roughly 48 grams? 1 mole CO2 is roughly 46 grams? Considering there are isotopes --------------------------------------------------------------- B: Do, at the same temperature and pressure, 1 mole CO2 and 1 mole O2 have the...

We feel a gas cylinder of cooking gas to be heavier if we lift it. But when a kid of 14 kg is lifted it feels a lot easier to lift him than lifting a cylinder of cooking gas weighing 14 kg. Is it because the pressure is low because of larger surface area of the kid?

Homework Statement A gas consisting of diatomic molecules that can rotate but not oscillate at a given range of temperatures expands adiabatically from pressure of 365Pa and volume of 70m3, doing 101J of work, while expanding to a final volume. What is its final PV (pressure volume) product...

Homework Statement I'm having a little trouble knowing when to use the ideal gas equations for entropy vs just the ones like this: (T2/T1)=(p2/p1)^((k-1)/k). I've noticed a pattern in the solutions for my homework( where you're finding isentropic efficiency of turbines and compressors) they...

Can anyone help on this problem encountered in gas chromatography: Two helium incoming gas lines A and B are connected together via a cross-shaped connector to two outlets C and D. All in and out lines are capillaries with diametre in the 0.1-1 mm range and lengths in the 10s of cm to 10s of...

Homework Statement One litre cylinder contains 1 mole of the ideal gas molecules having the average kinetic energy of 0.1eV. What is the total energy of this gas? Homework Equations W = K + U The Attempt at a Solution I figured because the cylinder is closed, no stated temperature change, or...

An ideal gas is compressed from a volume of Vi = 4.50 L to a volume of Vf = 3.00 L while in thermal contact with a heat reservoir at T = 295 K as in the figure below. During the compression process, the piston moves down a distance of d = 0.120 m under the action of an average external force of...

Dear PF Forum, Perhaps just yes/no answer would suffice. It's just out of curiosity and I can't find it on web. Or there are no answers :smile: Are there no noble gas compound? There are CH4, CO2, H2, O2 even O3 What about Helium, Argon, Neon? Are there really no compound with noble gas? If...

Homework Statement Questions are attached to this thread. Homework Equations P =mv (P is momentum) P = F/A (P is pressure) F = deltaP/delta t (P is momentum) The Attempt at a Solution I have managed to do questions a-e which I was very happy with but then moving onto the extension has made me...

https://www.physicsforums.com/attachment.php?attachmentid=20388&stc=1&d=1252066499When the partition removed, gas flows into the vacuum until all system has a uniform pressure. Now, is it possible to calculate the work? Let's say gas is not an ideal gas.(Freon 12) We know the volumes of both...

Qn : https://www.dropbox.com/s/dpcws9q4bjpzvtp/20151123_112037.jpg?dl=0 Why is option A and C wrong or correct? My attempted answer : A :A is plausible as if the piston is suddenly moved inwards, the gas molecules bounce off the piston at higher speeds Since Temp proportional to rms speed...

Homework Statement A gas has the following equations of state: P=\frac{U}{V} \,\,\,and \,\,\,T=3B\frac{U^{\frac{2}{3}}}{N^\frac{1}{3}V^\frac{1}{3}} where B is a positive constant. The system obeys the Nernst Postulate (S tends to zero as T tends to zero). The gas, at a initial temperature T_i...

Homework Statement I have the following task: Homework EquationsThe Attempt at a Solution But I don't understand how to solve it. Can somebody help me?[/B]

Hi, PF! I recently solved a problem from BSL which asked to analyze the following system used for determining the diffusivity of a binary mixture of gases. The left portion of the system, from the left bulb up to the stopcock at the middle of the tube, is filled with gas A. The right portion...

If you try to mix water and sand, the sand will mix around and eventually fall to the bottom. Sand and water can't make a solution, so they separate. However salt and water can make a solution, and they don't separate. If air is a mixture, why don't the gases separate? 1) So, pretty much what...

We have 2 (insulated) partitions, one with the gas, another vacuum, separated by a stop cock. We remove the cock, letting the gas expand into vacuum . I understand that since there is no opposing force on the expanding gas ,the work done by the gas is zero . But work done by gas is given by...

Suppose we have an insulated cylindrical container with a piston inserted from one end. Suppose the volume confined by the piston is full of a hot gas. Now let the gas drive the piston so that the volume is increased. Did the entropy of the system decrease because some of the energy of the...

Homework Statement 1 mm3 of gas at normal pressure and temperature contains about 1015 particles. Considering the particles as point-like and classical, provide a rough, conservative estimate for how many hard drives would be necessary to store the initial conditions of all gas particles. (As...

Homework Statement The task is the following: Homework EquationsThe Attempt at a Solution I calculated the derivatives for Vm (crit) and set them = 0, but somehow I can't solve the equation to obtain Vm (crit) on one side alone. This is how far i managed to do it: Can someone help me?

According to standard cosmology theory the physical momentum p of both massive and massless particles decay like: $$p \propto \frac{1}{a(t)}$$ where a(t) is the scale factor as function of cosmological time t (for a derivation see page 12 in the following lecture notes...

I am really stuck at this question. I tried to get the equation of volume with independent variables P and T, but the equation itself does not give a nice form, and thus I cannot get the derivative of V with respect to P. What should I do?

Hi Everyone, So I seem to have many problems understanding the Psychrometric chart and its physical meaning. First of all, I would be so thankful if you could introduce me a source which can be useful to physically and fundamentally understand the dew point, effect of pressure, humidity... and...

My daughter has the following homework problem we need assistance in confirming if we've understood and completed correctly. Homework Statement The Volume goes from 2.00 Liters to 7.00 Liters, the temperature changes from 800 kelvin to 150 kelvin, and the number moles of gas is quadrupled on...

Does anybody know of a way that I can protect a Google Sheet in such a way that it can only be edited via scripts? Ultimately I'm putting something together that acts as a very poor man's ticketing system. I have information displayed in a sheet and a set of buttons with scripts attached to...

I'm trying to compress a gas at max 300 psi. I'm making an air tank that will move a small turbine to make electricity. The problem, as I found out, is that 1L at 300 psi is not that much air and I need it to run for about a minute. When I fill my tank with air from a compressor, i run out of...

hi, so i want to ask why is the inert gas pressure in an incandescent bulb should be low? i thought that when the gas pressure is high, more 'free' tungsten atoms can collide with the gas particles (since the gas particles move at higher speed) and bounce right back towards the filament. hence...

What happen to gas particles at absolute zero? Is it possible that the particles will still be moving ? Thanks in advance

Homework Statement I'm given a initial and final pressure and temperature of an ideal gas to solve for the work done after it expans in a polytropic process (n=1.2) Homework Equations W = integral of P*dV PV = nRT PV = RT* PV = mRT PV^n = Constant The Attempt at a Solution I get W = integral...

1. For a van der Waals gas πT=a/Vm2. Calculate ΔUm for the isothermal expansion of nitrogen gas from an initial volume of 1.00 dm3 to 24.8 dm3at 298K. What are values for q and w?Homework Equations I looked up a for N2 gas to be 1.352 atm*dm6/mol2 dU(V,T)=(∂U/∂V)TdV+(∂U/∂T)VdT (∂U/∂V)T=πT...

When we discuss about Gas Law : [Charles Law, Boyle Law and Gay Lussac Law ] are they still applicable at super low volume and temperature. At such conditions, the gases would undergo phase transition and convert to solid. So will the Gas Laws still be applicable at that stage??

Homework Statement A gas in a piston-cylinder assembly undergoes a process for which the relationship between pressure and volume is pV2=Constant. The initial pressure is 1 bar, the initial volume is 0.1 m3, and the final pressure is 9 bar. Determine the final volume and the work for the...

I found this: http://adsabs.harvard.edu/abs/1992A&A...259L..31B document that describes how the X-Ray emissions from galaxy clusters are used to calculate the mass of the cluster. I'm unable to follow the steps to calculating the gas mass. Specifically, in section (2) there is a formula for...

Homework Statement Assume that in an alternate universe, the laws of physics are very different from ours and that "ideal" gases behave as follows: (i) At constant temperature, pressure is inversely proportional to the square of the volume. (ii) At constant pressure, the volume varies directly...

Hopefully this question makes sense; when talking about solubility of a gas does this have any relation to its ability to mix with another gas? i.e. gas solubility in gas, versus, gas solubility in liquid In ultrasonic cavitation some say that a more soluble gas can more easily enter the...

Moderator's Note: THIS HOMEWORK WAS POSTED IN ANOTHER FORUM, SO THERE IS NO TEMPLATE. calculate the change in entropy suffered by 2 moles of an ideal gas on being heated from a volume of 100L at 50C to a volume of 150L at 150C. for the gas Cv=7.88 cal/moleC. I'm really confused in entropy and...

... becomes a plasma? I am trying to find information on the species that will be present when a gas is broken down into a plasma for different types of gas and temperatures, is there a list somewhere, please could someone give me an idea of where I should look for this information? Also am I...

Homework Statement One m3 of an ideal gas expands in an isothermal process from 760 to 350 kPa. Determine the specific work done by the gas. Homework Equations ω=W/m 1W2=mRTln(P1/P2) = P1V1ln(P1/P2) P1V1=P2V2 The Attempt at a Solution P1V1ln(P1/P2) = (760)(1)ln(760/350) = 589.29kJ...

Homework Statement 96 grams of oxygen and 50 grams of hydrogen gas occupy separate, equal sections of 200 liter tank. The divide is removed and the gases are allowed to mix and react with each other. Temperature is kept constant at 120 degrees celsius 2. Homework Equations [/B] b) find the...

In my lecture, we were told that a nitrogen with a negative 3 charge has the largest radius compared to most of the other atoms in the same period. How is that possible? It has more protons attracting the valence electrons closer to the center, but the prof said that because three electrons are...

Does laser light from a powerful violet laser with wavelength 405 nm create significant ionization in a gas (Hydrogen or Helium) if shone through it? Will there be a streak of ionized molecules/atoms in the beam, so to speak? Can that ionization be detected easily with a voltmeter? How effective...

Hello, thanks in advance for your help, I am not a physicist, however have a fairly good grasp on mathematics, also this isn't homework or an assignment but a real world problem. Currently trying to create a system with a nebulising gas at a linear velocity of 350 m/s. The calculations...

Hi guys, I want to design a gas burner and combustion chamber. I use natural gas as fuel. I want to control air to fuel ration, so air flow has to control. I have an air compressor as air flow source. Clearly, it's needed a mixture tube before the combustion chamber. Now I have some...

Homework Statement Homework Equations Pv=nRt The Attempt at a Solution I already calculated V for a single molecule = 3.99x10^-23 m^3 and the cubic root of this volume gives 3.42x10^-8 m. However, I don't understand what I should do next. What does it mean to compare the value I obtained to...

Can someone please help me with the following proof ...I'm stuck and not sure if I'm even on the right path. Prove that What I've done so far; if U = f(T,V) dU = (∂U/∂T)v dT + (∂U/∂V)t dV Cv (non ideal) = (∂U/∂T)v Using dU = TdS - PdV and Maxwell relation (∂S/∂V)t =(∂P/∂T)v, (∂U/∂V)t =...

Homework Statement My problem is with the last line of the derivation. Usually, we take the rate of change of momentum (force) to be change of momentum divided by the impact time. But this slide of pp showed that the traveling time of the particle in the box is used but not the impact time. Why...

Neutral hydrogen gas in galaxy clusters Most galaxies are members of a cluster, a grouping of several to thousands of galaxies. Our Milky Way, for example, is a member of the "Local Group," a set of about fifty galaxies whose other large member is the Andromeda galaxy about 2.3 million...