Gas Definition and 1000 Threads

Homework Statement Consider a cylindrical parcel of air of area A and infinitesimal height dz. If this air parcel is to remain stationary, the difference between the total pressure forces exerted on its top and bottom faces must be equal to its weight. Use this information and the ideal gas...

If I have a box evacuated of air with 5 of the sides mirors and one side a heat conductor. will the photon gas inside have photons that get absorbed by the heat conductor and re-emitted when the photons strike the heat conductor

Homework Statement How can we calculate the velocity at stack tip if the distance of larger diameter is 2.5 m? I think i cannot use the equation of V1A1 = V2A2 because they may have some effect from 2.5 m of distance. Thank you very much. Homework Equations Q1=Q2 The Attempt at a Solution...

In a gas turbine engine(in aircrafts), why doesn't the gas after expansion move backwards towards the compressor? .How is it that it expands away from the compressor(rotating the turbine blades)? Will the pressure of air at the end of the compressor before the combustion chamber be higher than...

which soft wares are used in gas sensor simulation?

In the first volume of his lectures (cap 6-4) Feynman presents Maxwell's distribution of velocities of the molecules in a gas. And, referring to the PDF graph he says: "If we consider the molecules in a typical container (with a volume of, say, one liter), then there are a very large number N...

Hello, I'm a chemist and I'm currently working on my PhD on materials science. I'm trying to determine the pressure difference necessary to achieve the desired gas flow inside a chamber. The scheme of the chamber is the following: I have a big chamber which is evacuated to 0.2 bar, and another...

I need to pressurized argon gas from 1 bar pressure to 2 bar pressure. Flow rate outlet is 0.5 LPM. Can anybody suggest me a pump or compressor which is small in size? Minitiarised diaphragm seems good option but is it right one?

I've got a question that requires me to use the Van der Waals equation in the form: p(V-b)=nRT The process is isobaric, the volume changes from 1m3 to 2m3, and there is 1 mole of the unidentified gas. Ultimately, I need to find initial and final values of T. So I rearranged the formula...

The main aim of my question is to find time taken by gas filled tank while emptying (from full to zero) it into atmosphere? I require a set of equations which might be used in the calculation of such a situation. Known parameters are: 1. Pressure inside the gas tank. 2. Dimension and shape of...

I would argue that if you are computing the work done by an expanding gas in a frictionless piston, in an irreversible expansion where the inner pressure is greater at all times than the (constant) outer pressure, that you should integrate the internal pressure over volume change, not multiply...

OK, so I need to bring this one to the forum. I keep somewhat fanatical records on my vehicles. 69,450 miles ago there was a front end alignment done and the toe-in was set to +3/16" on the front end. My truck is a Toyota 4x4 which sees frequent off-road trips. Just over 1k miles ago I found...

Hi, I want to calculate the amount of liquid nitrogen (at boiling temp.) needed to build a pressure of 10.1 bar in a vessel of volume 66 m3. The liquid will be poured slowly into the vessel, boil off and fill the volume with gas at the specified pressure. I make the assumption that the process...

Homework Statement Consider a perfect monoatomic gas at pressure $p_i$ 1.2 atm and temperature $T_i$ 300K, that is in equilibrium inside a cylinder having a volume $V_i=1L$ and which piston has a mass of 1kg and is at an height of 50 cm. Admit that a mass M=3.13kg is over the piston. When that...

Homework Statement Some gas at 300K is enclosed in a container. Now the container is placed on a fast moving train.is the change in temperature of the gas the same as the change dT observed when train suddenly stops? Homework Equations 1/2mv^2=dU?? or dU=0?? The Attempt at a Solution...

Hi. I'm a mechanical engineer, but working as Safety Engineer. I have a question how to calculate the flow rate of hydrogen gas before a flow controller in case of leak through a 4.5 mm line at 35 bar pressure. Thanks in advance.

Copper pennies were placed into HCl which had been diluted with an unknown quantity of water. The pennies look cleaner, ... remain un-corroded (as expected). There is a slight bit of gas being produced , with no smell, but can cause discomfort to eyes. Bubbles formed on the pennies for the...

Hi, Joule's original gas expansion experiment is often presented like in the following link: http://demonstrations.wolfram.com/JouleExperimentOnFreeExpansion/ The apparent lack of temperature change in this experiment is often used in textbooks to demonstrate that the energy of an ideal gas is...

Homework Statement Homework EquationsThe Attempt at a Solution I don't understand which concept to apply in this question . The hint says to apply Bernoulli's equation and uses ∆P (excess pressure ) = (1/2) ρ v2 . This does give right answer . But I think this is wrong . We cannot apply...

Homework Statement Homework EquationsThe Attempt at a Solution Coefficient of volume expansion γ = ∆V/V∆T VT2 = constant Differentiating we get , T2∆V + 2VT∆T = 0 ∆V/V∆T = -2/T So , option 2) looks right . Is that correct ? How do I interpret the answer ? Does that mean the...

A quantity of ideal gas undergoes an expansion that doubles its volume. Does the gas do more work on its surroundings if the expansion is at constant pressure or at constant temperature? The answer in the book says W at constant temperature gives a greater value for the given case. But when I...

Homework Statement Homework EquationsThe Attempt at a Solution I have tried to change mass of oxygen into mol and I got ratio of oxygen and nitrogen. And I don't really know what to do.

Homework Statement :[/B] An astronaut visiting Jupiter’s satellite Europa leaves a canister of 1.20 mol of nitrogen gas 28.0 g/mol^2 at 25.0°C on the satellite’s surface. Europa has no significant atmosphere, and the acceleration due to gravity at its surface is 1.30 m/s2. The canister springs a...

Homework Statement Let 3/2kT be the kinetic energy of ideal gas per molecules. T the absolute temperature and N the avogadro number. Answer the following questions : 1) when the volume doubled at constant temperature. How many times the kinetic energy per molecule become greater than before...

Hello, As you can see in the attached hand drawing+calculation, my question concerns the typical method of evolved gas volume measurement by water displacement in an inverted graduated cylinder or "eudiometer". Once a bubble (cavity to be precise) of gas leaves the end of the tube through...

I purchased 22.752 gallons of gasoline containing +- 10% ethanol dispensing it into a 23 gallon gas tank. Then I drove 23 miles (mostly up hill) to a job site. At lunch time I was not able to crank the engine. The symptoms were clear, it was water in the gas. I have a video if you want to see...

Homework Statement From a previous post in this forum, unfortunately the thread is closed for answers otherwise I would have posted it there: https://www.physicsforums.com/threads/thermodynamic-filling-of-tank-matlab.479112/ A 70 ft3 rigid insulated tank contains air at 14.7 psia and 80 º F...

Homework Statement An ideal gas with molecules of mass m is contained in a cube with sides of area A. The pressure exerted by the gas on the top of the cube is P, and N molecules hit the top of the cube in a time Δt. What is the average vertical component of the velocity of the gas...

In general when one talks about an idealized gas, should/could one assume it is non-relativistic? (s.t E=p^2/2m will hold) many thanks

Homework Statement The problem is "A multicylinder gasoline engine in an airplane, operating at 2.40 10^3 rev/min, takes in energy 7.98 10^3 J and exhausts 4.50 10^3 J for each revolution of the crankshaft." and it wants me to find the liters of fuel consumed in 1 hr of operation if the heat...

I cannot find on google. Can you give me examples of living beings that are in the from of gas like water vapour or smoke or anything else that is a gas. Like jellyfish is made of water Humans are solid

Homework Statement A vessel contains a mix of helium and nitrogen (ideal gases). The ratio of the partial pressures is known: ##\frac{p_{N2}}{pHe} = 5##. The partial pressure is the pressure that a single component alone would exert. Homework Equations What is the value of ##\kappa = c_p/c_V##...

Homework Statement Die average kinetic energy and impuls squared of a single molecule are: $$<E_{kin}>= 6.5*10^{-21} J$$ and $$<p^2> = 1.8*10^{-45} kg^2m^2s^{-2}$$ Which gas ist it? 3. The Attempt at a Solution ##\frac{m<v^2>}{2}=\frac{<p^2>}{2m}## ##\Leftrightarrow## ##\frac{<p^2>}{<v^2>} =...

Homework Statement (a) Deduce from the thermodynamics identities: ##c_v=(\frac {\partial u}{\partial T})_n=T(\frac{\partial s}{\partial T})_n## and equations: ##f(ε)=\frac {1}{e^{ε-μ/k_BT}+1}## and ##u=\int \frac{1}{4π^3}ε(k)f(ε(k)) \, {d \vec k}##...

We know that for an ideal gas the differential of the internal energy function is: dU = n Cv dT But is Cv the molar heat capacity or not?

Hello, I am trying to calculate the price of Liquid Gas of 1 TCF - My researce revealed to me that: 1 - I know that 100 cubic feet (Ccf) of natural gas equals 103,700 Btu or 1.037 therms 2 - I know that price per MMBtu multiplied by 1.037 equals price per Mcf 3 - The price of one MMBtu is...

We are trying to design a new product which uses gas pressures in various ways. We are a little foxed about partial pressures: Imagine a small cylinder; 6in long + 1in in diameter. The cylinder is made from steel. The cylinder is divided into two equal compartments – A and B. Each compartment...

Hello, I would like to know, why is the volume of gas produced during phase change significantly more than the original volume of the liquid being used? Say water changing phase at 1atm.

We have a perfect gas in a closed box. On the top of the box there is a piston. We know that the molecules of the gas exert a pressure on the piston. Now let us put twice as many molecules in this tank, so as to double the density, and let them have the same speed, i.e., the same temperature. At...

Greg Bernhardt submitted a new PF Insights post Statistical Mechanics Part II: The Ideal Gas Continue reading the Original PF Insights Post.

Homework Statement Consider a one-dimensional metal wire with one free electron per atom and an atomic spacing of ##d##. Calculate the Fermi temperature. Homework Equations Energy of a particle in a box of length ##L##: ##E_n = \frac{\pi^2 \hbar^2}{2 m L^2} n^2## 1D density of states...

My parents were driving over the weekend with the windows open and I came up with another bunch of questions. With the windows open, would you use more gas than with them closed? I figured that when the windows are open and wind is blowing in, the wind is pushing in the opposite direction that...

Homework Statement If Cp for an ideal gas is 35.4 J/mol⋅K, which of the following is Cv for this gas? a. 12.5 J/mol⋅K b. 20.8 J/mol⋅K c. 29.1 J/mol⋅K d. 27.1 J/mol⋅K e. 43.4 J/mol⋅K Homework Equations ΔH = ΔE + Δ(PV) = Q + W + Δ(PV), and for ideal gas, ΔH = nCvΔT + Δ(nRT) = nCvΔT + nRΔT =...

Homework Statement Which of the following statement(s) is (are) correct when an ideal gas goes from an initial to a final state in a single process? a. No work is done on or by the gas when the volume remains constant. b. No energy is transferred into or out of the gas as heat transfer when the...

Homework Statement Homework EquationsThe Attempt at a Solution Honestly speaking , I have absolutely no idea about this problem .This doesn't happen often .In the KTG chapter , only definition and formula of Average , RMS and Most probable speeds is given . This question is for an...

MODERATOR'S NOTE: Moved from other forum, so no template @Chestermiller I am still having trouble figuring out if a given process is Quasi-static or not. Consider the following case. The cylinder consists of an ideal gas at the bottom and a liquid of density ρ at the top separated by a piston...

How many things can go wrong simultaneously and apparently independently with a gas central heating system? Mine has been stretching credulity to the limits last weekend. Saturday afternoon, we noticed house getting cold and spotted that pilot light was out. Couldn't get it to relight at all...

1. The problem statement, all variables and given/known Homework Equations ## \frac {PV1}{T1} = \frac {PV2}{T2} ## The Attempt at a Solution I find that v2 = 330/273 V1 But how can this related to the distance of P travel? Also, as the A gas pressed to B, i think the B gas try to resist. But...

I was working at the observatory and uh someone came in with a question about landing in Jupiter- right away my brain was like no, it’s a gas giant and there’s too much pressure for a probe to make it to the solid surface, but I’ve also been trying to think of it in terms of the force applied by...

Do you know where I can find a formula to calculate how long it would take to drain a cylinder under pressure to atmospheric pressure? if I know the volume of the cylinder and the size of the opening.