Gas Definition and 1000 Threads

Hi, An irreversible gas expansion is often described in textbooks with a compressed gas in a cylinder pushing up a weight (with mass m) via a hypothetical friction-less and weightless piston. It is said the work done by the gas is equal to -mg × h and from this you can derive the work for a...

Hi Folks, I am exploring using Ultrasonic for LGP tank level measurement. I went through lots of readings, in particular use of SRF02 sensor. But, It's not conclusive. Anyone has been exposed to solving such problem? If yes, kindly share return on your experience. Appreciate!

I'm trying to relate an analogy from Brian Greene about entropy microstates/macrostates to the real world. In the analogy, you have 100 coins that you flip. The microstate is which particular coins landed heads up. The macrostate is the total number of coins that are heads up. So a low entropy...

This above is the diagram I'm not too sure about the solution to this problem as to why I came here. Is it something to do with photons having different frequencies i.e emitting different amounts of energy based on its frequency

I am working on a project where I have to calculate various results relating to the motion of a water bottle rocket being launched. I am currently stuck on trying to find how long the thrust period of the rocket is. The model for the rocket is as follows: It is a 2L (0.002m3 bottle filled with...

Given this problem I have calculated the partition function as $$z=1+e^{-\beta E_1}$$ And calculated the average internal energy as $$<U>=\frac{E_1 e^{-\beta E_1}}{1+e^{-\beta E_1}}$$ And thereafter taking the partial derivative of <E> with respect to temp. T the specific heat obtained is...

As I understand both cations and electrons are produced between cathode and anode in a gas discharge, but what is their imminent fate, during and post discharge event? The majority of information I could find only covers the electrons from the time of the first ionization event to impacting the...

A gas of bosons or fermion particles follows a particular quantum statistics. Then why a molecular gas (say, H2) follows a classical distribution statistics? Is it not the case that the molecules should be indistinguishable one from another and be either bosons or fermions? What is exactly the...

It is said that, for real gases at high pressure, the measured volume is higher than the calculated volume. My perception of the volume of the gas, as of now, is the following: The free space available for the gas to move. It excludes the volume of the molecules. So on increasing the pressure...

Summary:: NO TEMPLATE BECAUSE THIS HOMEWORK PROBLEM WAS MISPLACED IN A REGULAR FORUM Cant do part c, using the steady flow equation I am confused how to continue. Please help! Mainly confused as to what heat transfer loss represents in the steady flow equation and where to go to find the...

If we assume the energy of particles in an ideal gas follows a Boltzmann distribution, then the energy distribution function can be defined as below: , where k_B is the Boltzmann constant Since the energy of particles in an ideal gas are assumed to only consist of translational kinetic energy...

What do I see in my solution is : ΔW + ΔQ = W_pv + W' + ΔQ (A little difficult to perceive the useful work ) Work on the environment : -p0*(-ΔV) (WHY negative sign?, Is this the work ON the gas?) ΔV=nR (T0/p0 -T/p) By TdS = dQ ΔS + ΔS0 =0 Reversible case: ΔU= -T0ΔS - (-p0(-ΔV)) + W' (WHY...

First of all I thought it was necessary to calculate the temperature(the only data missing for the formula) using the ideal gas equation(since I've already been given 'p' and 'V'), and plug it in the 'v' formula, but the problem immediately occurred when i tried to find out the number of...

Hi everyone, even before addressing the following points I have a serious issue in understandig the text of the Exercise.My idea was to model this system with a lattice gas. Given that each site can host 2 atoms I have 3 possibilities for each site: I'll call'em ##S_{11} S_{00}## and ##...

In the early parts of the books, Mars' ambient atmo pressure (and temperature) was increased, including not just CO2, but oxygen as well. It rose to the point where they only needed masks that let through oxygen but not CO2. In my amateur view, I would expect that this would not work very...

In these lecture notes about statistical mechanics, page ##10##, we can see the graph below. It represents the distribution (probability density function) of the kinetic energy ##E## (a random variable) of all the gas particles (i.e., ##E=\sum_{i}^{N} E_{i}##, where ##E_{i}## (also a random...

1- ##\delta P_V =(\frac{\partial P}{\partial T} )_V \delta T_V## 2-##\delta V =(\frac{\partial V}{\partial T})_P \delta T+(\frac{\partial V}{\partial P})_T \delta P## so ##C_v \delta T=-P\delta V=-P((\frac{\partial V}{\partial T})_P \delta T+(\frac{\partial V}{\partial P})_T \delta P)## I can...

I expanded it as shown above and got ##<v²> + <\bar v²> - 2<v><\bar v>## = ##v_{rms}^2 + \bar v^2 = \frac {3kT} m+\frac {8kT} {πm}## I used ##<v> = 0## as the velocity is equally likely to be positive as it's likely to be negetive. From the above I get the answer ##\frac {kT} m(3+\frac 8...

A trial has commenced at Keele University in the UK where 20% Hydrogen is injected into the domestic gas supply. In this way it can be stored and then utilised by existing domestic burners. Can this be a quick solution to reducing domestic CO2 emissions? Or is it better to use battery storage...

How is it proved that Van Der Waals gas is a second order phase transition? The second order derivative of the pressure (P ) with respect to volume ( V ) don't have a discontinuity ( except at point V = Nb , but the pressure is not existent for V<=Nb ). So how come Van der waals gas describes...

There is a physics event being organized in my college for which I had planned to make a muon detector. I have the circuit ready which brings 240 volts ac mains source down to 80 volts dc supply. But now, I am facing a serious problem. I have been unable to find a neon glow lamp. Basically, mý...

First calculate the total pressure, but that gives me p2=p1*t2/t1 = 2,86 bar and partial pressure of 0,87 bar which is wrong. any tips?

This is the problem below that I have tried doing I ended up getting the mass of gas ejected to be 1.25kg from doing the following Would you say this is a reasonable value to get Thanks in advance!

It looks more like a computational obstacle, but here we go. Plugging all of these to the partition function: $$Q = \frac{1}{N! h^{3N}} \int -\exp(\frac{1}{2m}(p^2_{r}+p^2_{\phi}/r^2+p^2_{z})+gz)d\Gamma=$$ $$= \frac{1}{N! h^{3N}} \int \exp{(\frac{-1}{2m}p^2_{r})}dp_{r_{1}}...dp_{r_{N}}...

When modeling stellar structure and formulating equation of states, I've seen various cases where you have to take into account whether the constituent gas of a star is degenerate or not. But how do you determine if the gas is degenerate or not?

Anyone who has an idea for how to calculate the irradition [W/m2] to the base of a cylinder with radius R, height H, absorption coefficient k, and temperature T? I've looked at the approach with mean beam length by Hottel but cannot figure out what to do when it is the base of the cylinder that...

Since the assignment asks the work done by the gas, that should be equal to P1*(V2-V1) aka the area under the P1 line. Do I have to subtract the work done to the system or is this the solution already? If so, why do I need P2?

I thought to myself , have there any been any physical attempts or calculations in theory about the possibility of creating a net electrical gain of energy from a pulsed fusion approach where a high pressure/density gas mixture is prepared constantly within a container and a high current pulse...

Let's say I have a liter of gas at pressure of 4 atm and T=900K. I use it to move perfect massless frictionless and insulative piston to compress a liter of 1 atm, T=300K gas. When the pressure on both sides is equal and the piston stops moving, will the temperature on both sides of the piston...

I guess this applies to wood-burning fireplaces as well, but they will require more frequent reflector surface cleaning. Our gas fireplace is fairly warm, but it's clear that it's not as efficient as it could be. It seems like reflective back and side inserts would reflect a lot more of the IR...

Can we Carbon Date a Gas or must it always be a solid?

How to calculate entropy from positions and velocities of gas molecules? lets say we have 2 different gases. entropy should be bigger after mixing them, than before when these are separated. But how to calculate exact entropies by knowing only positions and velocities of gas molecules?

Hi, some time ago our professor told us (en passant) to evaluate this quantity: $$<F|n_m( \mathbf x) n_{m'}(\mathbf x) |F> - <F|n_m( \mathbf x)|F><F|n_{m'}(\mathbf x) |F>$$ And then he said: "you'll find that this quantity may not be zero. In particular when the electron are correlated it will...

It is well known that the 2D free electron gas fermi momentum can be expressed as follows, k_F=\left(2\pi n\right)^{1/2} where n is the electron surface density. Assuming this 2D electron system can be considered as 2-D tight-binding square lattice whose eigenergy can be written as...

Why we do not considered the translational energy of the gases particles in the internal energy due to ordered motion but only due to random motion.

. We have that energy in a infinitesimal Spherical layer with number of mols dn is: dU=Cv.T.dn (1) But by the ideal gas law: PV=nRT (2) Differentiation gives: PdV+VdP=RTdn (3) (3) in (1) and using CV=3R/2 (monoatomic) gives: dU=3/2.(PdV+VdP) (4) Integration of (4) over the whole gas will...

This is a question in my midterm. I calculated for the answer as c) 11.7 atm by the Ideal Gas Law. The professor states that "all the air is originally at 1 atm" in the prompt indicates an idea of "both 70 L of air and existing 6 L of air in the tank are at 1 atm", and he grades d) 12.7 atm as...

In the first question should I remove the delta and put d or that doesn't make a difference and on the second question should I substitute the values of R, K, Cv and Cp or that's not required I'm not really sure how correct is my answer to the second question

Summary: U=3/2*n*R*T Can some of you help me with this The total internal energy of an ideal gas is 3770 J. If there are 3 moles of the gas at 1 atm, what is the temperature of the gas? I use U=3/2*n*R*T but get the wrong answer, (101 K) but it should be 303 K [Moderator's note: Moved from...

I have attached the full answer in PDF file. I'm not sure about the answers. will really appreciate if they get checked

I find that $$U=\int Z \epsilon D(\epsilon) e^{-\epsilon β}d\epsilon=\frac{gV}{(2\pi)^3}\int Z \frac{(\hbar)^2k^2}{2m}k^2 (4\pi)e^{-β\frac{(\hbar)^2k^2}{2m}}dk$$ where g=2s+1=2, $$Z=e^{βµ}$$ and $$D(\epsilon)=\frac{gV}{(2\pi)^3}k^2 4\pi$$ for the density of states From here, I can use $$c_v...

It is my assumption that I need to find the chemical potential of the atoms $$\mu_A$$ and for the molecules $$\mu_{A_2}$$, then use $$\mu_{A_2}+\mu_{A}=0$$ to arrive at the given identity. For $$\mu_A$$, I found that $$\mu_A=k_BTln(n_A\lambda ^3)$$, where $$n_a=\frac{N_a}{V}$$ and $$\lambda$$...

A mega-maser-emitting blob of gas is in orbit around a massive black hole in the centre of a galaxy. The black hole has a mass of 106 solar masses, and the blob of gas is in a circular orbit one light year away. What is the speed and acceleration of the blob?

Part (a) ΔS = ∫ (dq/T) because: dq = PdV = (nRT/V)dV Then: ΔS = ∫ (1/T)*(nRT/V)dV ΔS = nR ∫(1/V) dV ΔS =nR[ln(V2/V1)] Part (b) This is where I'm stuck. I know [P + a/(v/n)2][v/n - b] = RT can be solved for P and simplified to P = [RT/(v-b)]-[a/v2] since n=1mol But I don't know how to proceed...

Has anyone created a thread on Free Body Diagram on assembly having many components ? For example a Casing having premium threads in both end and a set packer within it. What would be the FBD equations to determine various forces and reaction forces

P1= 13.6 V1= 1.1 T1= 22 P2 = 14.4 V2= x T2 = 32 my answer is 1.51L am i missing something?　

Hello guys. I really try to understand the problem, can you please help.

Summary: Hello, I need some help with this problem since my professor is bad at explaining (he reads a book and repeats everything), there's a problem online similar, but values and what is asked is different. A gas stream (1) contains 18 mol% (40.2 mass%) hexane and remainder nitrogen flows...