Adiabatic Definition and 498 Threads

From a video lecture, it is mentioned that "dU≠dW in Joule's free expansion if the process is irreversible and adiabatic" Mentioned in around 36:00-38:00 in the video: What I would like to ask is why in this irreversible adiabatic process, dU≠dW? Is it because the W here doesn't include other...

Homework Statement Consider an ideal monatomic gas that undergoes an adiabatic free expansion starting from equilibrium state A with volume 500 cm3, pressure 40 kPa and temperature 300K to state B, which has a final equilibrium volume of 1000 cm3. Construct an reversible isothermal path that...

Hi guys, I have a question to you that has been bothering me for a while now. It is about adiabatic flow in a duct or more specifically in the air intake of a jet engine. In lectures and textbooks it is always stated that the total temperature in an adiabatic flow does not change. Hence the...

Regarding interacting green's function, I found two different description: 1. usually in QFT: <\Omega|T\{ABC\}|\Omega>=\lim\limits_{T \to \infty(1-i\epsilon)}\frac{<0|T\{A_IB_I U(-T,T)\}|0>}{<0|T\{U(-T,T)\}|0>} 2. usually in quantum many body systems...

Homework Statement A pocket of air rises 1000 meters. Estimate how much it cools. Use the atmospheric law to determine pressure at 1000 meters. Homework Equations P = P0 * e-Mgz/RT PVγ = constant TVγ-1 = constant The Attempt at a Solution Using the atmospheric law, I found the pressure at...

Homework Statement In an adiabatic irreversible expansion of ideal gas , if Pext = 0 then which is true, A. T2=T1 B. Q=0, C. P1V1= P2V2 D. P1V1γ= P2V2γ Homework Equations ΔU = Q - W For ideal gas, PV= nRT[/B] ΔU ∝ ΔT The Attempt at a Solution I know Q= 0, Work done is zero, So ΔU = 0, hence...

Homework Statement Please see images - full problem statement given. Summary: I have to calculate TL for an adiabatic tip extended surface I found all the equations for points 1-6 but cannot figure out 7. Homework Equations 1st BC: θ(0) = Tb - T∝ 2nd BC: x=L The Attempt at a Solution If it is...

Is work done in adiabatic process quasi static or not?

Homework Statement (56th Polish Olympiad in Physics, 2007) We have a tube of mass ##M##, consisting of two segments of diameters ##d_1, d_2##. The pistons (see the picture http://www.kgof.edu.pl/archiwum/56/of56-2-1-R.pdf) have mass ##m_1, m_2##. At the start the air inside had pressure...

Dear everyone, Now, I'm reading some papers on the "Curvaton Mechanism"(eg.http://arxiv.org/abs/hep-ph/0110002v2 as the original literature.) Here I have some confusion on this topic. (1) Why the primordial perturbation of curvaton field is initially isocurvature-type? When the inflation driven...

Homework Statement Air is compressed at room temperature from atmospheric pressure to ##\frac{1}{15}## of the initial volume. Calculate the temperature at the end of compression assuming the process is reversible and adiabatic.Homework Equations ##pV^\gamma = constant \Longleftrightarrow T...

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}...

An adiabatic diffuser is employed to decrease the velocity of an airstream from 220 to 30 m/s. The air enters the diffuser at a rate of 8 kg/s with a temperature of 300c and a pressure of 100kpa. Determine the exit area of the diffuser if the exit pressure is 125kpa. Answer is 0.37 m^2 Guys I...

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...

This example is taken from the wikipedia page describing irreversible processes. I just want to make sure I understand correctly why the initial state can't be reached anymore. I assume the transitions to be quasi-static, but there is friction between the piston and the cylinder. If so...

Hi there, I was wondering if you could help me, I think I may have some concepts wrong or incomplete. Homework Statement We have an adiabatic cylinder of volume ##V_1## filled with a gas of pressure ##p_1## and temperature ##T_1## in thermal equilibrium, closed with a piston. All of a suden...

In class we're currently learning about reversible and irreversible adiabatic processes. For reversible process, we got dq=0, so dU = dw = -P*dV = Cv*dT. What I don't get is where did the Cv*dT come from? I remember q=C*dT, but dq = 0 so I'm not sure what that means? Also, where does Cv*dT...

Homework Statement Prove the relationship between the pressure, P, and the temperature, T, for an ideal gas with a reversible adiabatic expansion. Base the proof on the first law of thermodynamics and the ideal gas law. The relationship is: T^(Cp,m/R)/P = constant Where R is the gas constant...

My textbook says, basically, for an adiabatic process... All three variables in the ideal gas law—P, V, and T—change during an adiabatic process. Let’s imagine an adiabatic gas process involving an infinitesimal change in volume dV and an accompanying infinitesimal change in temperature dT. The...

I am going to report about Adiabatic process, specifically in cloud formation. Can someone help me some important points to consider?Im more concerned in cloud formation only since my topic is limited in that matter. 1. What is the science behind the adiabatic process in clouds? 2. Some...

I am having trouble calculating the work done by a product gas in reversible adiabatic expansion, and in calculating the final temperature. pV gamma = constant, Cv = constant (assume), gamma = cv + nR / Cv. anyone who can help me out?

Homework Statement 8.02 × 10−1 moles of nitrogen gas ( γ= 1.40) is contained in a volume of 2.00 × 10−2 m3 at a pressure of 1.00 × 105 Pa and temperature of 300 K. The sample is adiabatically compressed to half its original volume. IT behaves as an ideal gas. (i) What is the change in...

Isentropic means a process where entropy remains constant. Now formula for entropy is ΔS = ΔQ/T now in an isentropic process, ΔS=0...so that means ΔQ = 0 ...right? but if ΔQ = 0, that is an adiabatic process. so are isentropic and adiabatic processes are...

Homework Statement A gas of volume 1400[liter] and pressure 2.33[atm] expands in an adiabatic process to 2240[liter] and 1.2[atm]. plot the process on a V-P diagram. I shorten the question, only this interests me. the number of moles is given. Homework Equations Equation of state: ##PV=nRT##...

Hello everyone, I wanted to ask you if the universe is an adiabatic system where the energy it can't be transmited outside itself. If is an adiabatic system, what happened with the information and energy inside a black hole? How the universe started with a 0 entropy state? Could be the...

when the gas effuse out of an insulated container, its velocity is given by \sqrt{\frac{2\gamma RT}{(\gamma-1)M}} (irodov's problem 2.42) This leads to the result that every mole of leaking gas has an energy of \frac{\gamma RT}{(\gamma-1)} whereas we know the energy contained in 1 mole of gas...

I Think I understand this, but when I look it up, I keep reading about work done and energy used, which puzzles me. The simple way I have always thought about it is, when you expand a gas you also expand the heat it contains, so while it contains the same amount of heat, it's concentration...

why are isothermal process values higher than adiabatic process ones? I know that the volume is powered by gama in adiabatic process ones, and this has an effect. but how can I explain it ?! http://www.popsolving.com/Thermodynamics/Problem2.4_Freebody.jpg

Homework Statement By how much does the temperature of an ideal monatomic gas change in an adiabatic process in which 4.0kJ of work are done on each mole of gas? By how much does the temperature of an ideal diatomic gas (with molecular rotation but no vibration) change in an adiabatic process...

Homework Statement One mole of gas A, two moles of gas B, and one mole of inert gas I are fed into an adiabatic reactor of variable volume and constant pressure at 25 °C. At this temperature, the reaction yielding liquid R proceeds normally as: \textrm{A} (g) + \textrm{B} (g) \rightarrow...

If I heat a rubber balloon filled with helium slowly and if the balloon is fully expandable and (the balloon) can be assumed to require no energy in its expansion,what type of thermodynamic process is taking place? Is it isobaric? Since the balloon expands the pressure exerted by the gas on...

We have a situation. Someone modified the exhaust pipe from a diesel fired equipment. Exhaust gas flows out through a 30mm internal dia pipe. The modification carried out was to reduce the diameter of the pipe to 20 mm internal dia. The Exhaust outlet temperature from the equipment was 400 deg...

Homework Statement a) For a certain ideal gas CP = 8.58 cal mol-1 K-1. We have 2 moles of said gas at 293.15 K and 15 atm. Calculate the final volume and temperature when the gas expands adiabatically and reversibly until it reaches a pressure of 5 atm. (Answers: V = 7.45 L; T = 227.15 K) b)...

< Moderator Note -- Thread moved here to Homework Help forum > One volume of CH4 is mixed with V volumes of air (78 vol.% N2,21 vol.% O2,1 vol.% Ar) at 1 atm and 25°C; then the mixture is ignited. Find the temperature of adiabatic combustion (the adiabatic flame temperature). The volume of air...

Hello everybody, I'm trying to understand if is possible to say something about the Floquet exponents, in the limit of a very slow changing on time. I try to explain. Given the differential equation $$ \dot{\vec{v}}(t) = A(t) \vec{v}(t) $$ with $$ A(t+T)=A(t) $$ a monodromy matrix is given...

Say there is a parcel of air rising and cooling, what is going? Is it that the net kinetic energy (Temperature) of the parcel is distributed over the (new and larger) area/volume? Or Is it that the parcel is undertaking work as it presses outwards and so looses a corresponding amount of kinetic...

Hi, What books/book chapters are good for learning adiabatic elimination in great depth? Thank you.

Hi, this is my first post on here. My question relates to adiabatic cooling/heating of a gas. I am trying to grasp the idea conceptually rather than being able to explain it mathematically per se... When gas escapes rapidly from a pressurised cylinder the rapid expansion of the gas is...

Homework Statement In a diesel engine air is adiabatically compressed to autoignition temperature (287oC) of diesel. Given C/nR=2.78 for air, and the room temperature is 27oC, what is the compression ratio where diesel vapor is added for ignition.Homework Equations PV=nRT PV=NkT C=(dU/dT) The...

Homework Statement Hi, I did a lab experiment where I took a 5L vessel made of some material that isolates gas inside and thus behaves like an isolated system (adiabatic). I then pumped gas from ~90kPa to up to 150 kPa... recorded the temperature, then let the gas 'expand' by opening the...

I would like some insight on a problem I have been working on. I have a seal container of air where the outside chamber has a slight temperature differential between top and bottom. I understand this causes a density variation in the air between the top and bottom of the chamber. Now I am...

Please help me qualitatively in the following points : 1) If in a system(consider a cylinder) fixed with a piston , if the piston is moved suddenly then how can a process be adiabatic. 2) I understood that the process would be irreversible but, if the process is adiabatic then is the relation...

(1) Exact form of U exists because of the results of experiments in adiabatic work, what are such experiments which gives proof for above statement? (2) Is differential of Internal energy dU path dependent?

1. Homework Statement The following describes a method used to measure the specific heat ratio ##\gamma = c_p/c_V## of a gas. The gas, assumed ideal, is confined within a vertical cylindrical container and supports a freely moving piston of mass ##m##. The piston and cylinder both have the...

Homework Statement As per attachment. Part iii How would you do this question by integrating the work? Homework Equations W = - ∫P dV PV^gamma = constant The Attempt at a Solution So I integrated the work with P= constant/ V^gamma and came up with this: W = constant* (...

Hello, to the best of your knowledge, what is 1) the gas with the lowest adiabatic index ##\gamma=\frac{c_p}{c_v}## at room temperature 2) a very common, non-flammable, non-toxic gas with the lowest adiabatic index at room temperature Many thanks

Homework Statement An ideal gas with Cv = (5/2)R, and Υ = 1.40 undergoes an adiabatic expansion until it has a pressure of 1.0*10^5 Pa and a volume of 2.0m^3. It then undergoes an isothermal contraction of T=300K until it has a volume of 1.0m^3, and then undergoes an isochoric (constant...

1) What is the reason why dH!=0 for an adiabatic(q=0) reversible process? The mathematical argument is irrefutable and it is clear that it has to do with the process not being isobaric: ΔH=ΔU+PΔV+VΔP , ΔU=work=−PΔV Therefore, ΔH=VΔP and this is not 0. However, I do not understand it...

I recently have discovered that the thermodynamics term "adiabatic" seem to be used slightly differently in Britain than it is in North America. What does "adiabatic" mean in Britain?

No heat exchange is facilitated during an adiabatic process. Change is heat is zero. How does this relates to the entropy being zero? ∫dQ/T? But this could really just mean that the integral is of any constant.