Adiabatic Definition and 470 Threads

Just a question that will hopefully improve my lack of understanding. A thought experiment. I have two cylinders both with frictionless pistons constrained to move in the z direction (against gravity) the same distance in both. So, the intial volume and final volume will be the same for both...

Homework Statement A sample of 2.5 mol O2 (Cp,m = 29.355 J K-1 mol-1) is originally confined in 23 dm3 at 270 K and then undergoes adiabatic expansion against a constant pressure of 600 Torr until the volume has increased by a factor of 3.0. Calculate q, w, ΔU, ΔT, and ΔH. (The final...

I am aware of the derivation for the dry adiabatic lapse rate using the enthalpy approach: ncpdT+VdP=0, but I can't seem to spot the error in my own derivation. If anyone sees it, I would be especially grateful. dU=\deltaQ-\deltaW ncvdT=0 - PdV \frac{dT}{dV}=-\frac{P}{nc_{v}}...

air enters an adaibatic nozzle steadily at 300 kPa, 200 degree celcius and 30m/s and leaves at 100 kPa and 180 m/s. find the exit temperature? when m using energy balance equation: h1 + [ (v1)^2 / 2 ] = h2 + [(v2)^2 / 2 ] i get the answer 184 degree celcius. but when i use the other...

Hi, I am going through a book on thermal physics (specifically on a section on the 2nd Law) It talks about an extremely fast adiabatic expression (as a gas in one flask separated by a valve to another flask in vacuum and then the valve is opened). What I fail to understand is that...

[SOLVED] Adiabatic Hot-Air Balloon Rising Question Homework Statement A large research balloon containing 2.00 x 10^3 m^3 of helium gas at 1.00 atm and a temperature of 15.0 degrees Celsius rises rapidly from ground level to an altitude at which the atmospheric pressure is only 0.900 Atm...

Homework Statement A flexible balloon contains 0.375 mol of hydrogen sulfide gas H2S. Initially the balloon of H2S has a volume of 6750 cm^3 and a temperature of 29.0 C. The H2S first expands isobarically until the volume doubles. Then it expands adiabatically until the temperature returns...

Homework Statement The slope of an adiabatic curve will be equal to r times the slope of an isothermal curve only when we use the ideal gas equation Homework Equations The Attempt at a Solution Adibatic process, P(V)^g = constant Differentiating w.r.t V...

I need to solve this problem. A big balloon with volume V1 = 2.00 * 10^3 m^3 contains helium at 15 degrees celcius and 1 atm. The balloon now rises from the ground to a height 'h' where the pressure is 0.900 atm. The process is adiabatic: a) find the volume at height h b) find the...

So, I am looking a question about adiabatic expansions and the associated entropy changed. Why exactly is the change in entropy for a reversible adiabatic expansion/compression equal to zero? The book says its because there is no heat transfer, but for irreversible adiabatic processes, there...

Hi, When a gas is compressed, its temperature increases. But what is the formula to calculate this rise? Could you please explain the formula too. This isn't homework btw! Thanks!

Homework Statement During an adiabatic process, the temperature of 5.50 moles of a monatomic idea gas drops from 495 C to 215 C. For this gas, find (a) the work it does, (b) the heat it exchanges with its surroundings, and (c) the change in its internal energy Homework Equations I know...

I've been working on this proof, and I just can't get it backwards or forwards, so I must be going about it wrong or missing something. I'm on a re-do for the homework, because my first attempt was completely wrong, so here I go with the second. Any guidance would be appreciated. Homework...

Homework Statement I have the equation for the internal energy: U = (f/2) * N * k * T, where f is the degrees of freedom, N is the number of molecules, k is Bolzmann's constant and T is the temperature in Kelvin. This can be written as U = (f/2)*p*V using the ideal gas law...

Homework Statement Show that when an ideal gas expands adiabatically, the temperature and pressure are related by the differential equation: \frac{dT}{dP} = \frac{2T}{5P} Homework Equations Ideal gas law The Attempt at a Solution PV = nkT T = \frac{PV}{nk} \frac{dT}{dP} =...

Homework Statement 1.Show that PV^Y is a constant for adiabatic,quassistatic expansion of a photongas and determine Y 2. Show the same for full degenerate gas of fermions at T=0 Homework Equations The Attempt at a Solution Plz help thx

You have two cups, one with m1 = 2.73 kg of water at t1 = 42.32oC and the other with m2 = 1.88 kg at t2 = 21.34oC. You mix the two in an insulated thermos. What is the final temperature of the water? I'm pretty sure that this is supposed to be an adiabatic process, because you are trying to...

I want to know if in rapid adiabatic compression of a gas, is work done by gas on surrounding (atmosphere) numerically same as work done by surrounding on the gas. Please tell if there exists some solid proof of the answers you guys are giving.

This question came some time back in Stony Brooks exam. I have the solution also. But i am having some conceptual doubts. Can someone help me please. The question is: Consider ‘n’ moles of an ideal monoatomic gas placed in a vertical cylinder. The top of the cylinder is closed by a piston...

Homework Statement 2 moles of Carbon monoxide gas start at a pressure of 1.2 atm and a volume of 30 litres. The gas is then compressed adiabatically to 1/3 this volume. Assume that the gas may be treated as ideal. What is the change in the internal energy of the gas? Does the internal energy...

Hi, I'm thinking about how to derive an expression for the final temperature (call it T2) and the work done (call it W) in an adiabatic compression, when you only know the initial and final pressures (call them P1 and P2), and the initial temperature (call it T1). I'm not sure about my...

Hey everyone =) This is my first post here but I've been lurking for a while. Anyway, so i am taking this physical chemistry class and I can't seem to solve this problem. I think it is still a physics problem. Anyway, it goes like this: small amount of moles of steam (.83 moles) @ 100...

1) Is there any way for the entropy to increase in an closed adiabatic syatem? 2) what are the mechanisms of entropy generation within a closed thermodynamic system? Thank you

Homework Statement The molar energy of a monatomic gas which obeys van der Waals' equation is given by E = (3/2)RT - a/V V volume, T temperature, a is a constant. Initially you have T1 at V1, and the gas expands adiabatically in a vacuum so that you have V2. What is T2? Homework...

Hi, I don't fully understand this thing. I've read it on wiki, but it just doesn't get through. Perhaps I am a dumbass. I've 3 questions that hopefully will help clear it up. 1) How do you stop adiabatic cooling? 2) In a closed and insulated system where there is a compressed gas...

To Forum Physicists / Administrators... Equations for an ideal gas undergoing an adiabatic process are 3 viz 1) P(v^g)=const 2)T(V^(g-1)) =constant and 3)T(P^((1-g)/g))= constant where g=specific heat for const pressure/specific heat for const volume.These equations suits the Ideal gas...

Homework Statement A sample of 5 moles of nitrogen gas (γ = 1.40) occupies a volume of 3.00 × 10^−2 m3 at a pressure of 2.00 × 10^5 Pa and temperature of 280 K. The sample is adiabatically compressed to half its original volume. Nitrogen behaves as an ideal gas under these conditions...

If a gas is adiabatically compressed and the calculated change in internal energy is 1600J, is the WORK done on the gas also 1600J??

If a process is adiabatic and reversible, such as a gas in a tube that has been compressed, is it true to say that there is no change in entropy from the gas being uncompressed to being compressed? If not, why not?

An ideal gas at a temperature of 17.7°C is compressed adiabatically from an initial volume 70.0 l to a final volume 43.0 l. Find its final temperature (in °C) if CV = 2.50R. so T1V1^g=T2V2^g to find g=cp/cv=(cv+nR)/cv and cv=2.50R g=(2.50R+nR)/2.50R factor out an R...

Homework Statement 3.14 (0.5) How is the fractional change in temperature related to \frac{dT}{T} the fractional change in pressure \frac{dP}{P} ? (IPhO 2006) Homework Equations PV^{\gamma}=\rm constant The Attempt at a Solution nC_vdT=-PdV (1), dV/dP=-nRT/(P^2) If I...

fully adiabatic process? :confused: by definition i know that adiabatic process is a thermodynamic process in which there is no heat transfer and it the same time i also know that nothing is frictionless even though we sometimes assume thing to be. so therefore there will be always heat...

:confused: :confused: i was reading my lecture note over the half term but i am still a bit confused and i was wondering if someone could describe in detail, using a p-v diagram, a well known engineering cycle which specifies a isothermal or adiabatic process. Thanks you very much

Homework Statement It is said that the work done between 2 isothermals is independent of the adiabatic. Homework Equations The work done during an adiabatic process is given by, W = C(v){T1 – T2) The Attempt at a Solution From the above equation it is clear...

Why is it when the conditions are adiabatic and reversible about a turbine, the assumption is its isentropic?

I have tried every combination of terms that I can think of within PV=nRT to find nR. Here are the three expressions that I have come up with, none of which are correct based on the answer to this question... nR = 100 * 0.01e-3 / 300 (the expression with kPa as the units of pressure) nR...

Hey! "Calculate the work done on 1 mole of a perfect gas in an adiabatic quasistatic compression from volume V1 to V2." The work done on the gas in this compression is: -\int_{V1}^{V2} P dV Because we are talking about an ideal gas the ideal gas law applies so...

Adiabatic heat exchanger problem... Please Help! I have this proplem as a homework assignment and I'm a bit stuck as houw to set it up. Here it is: Propane gas enters a continuous adiabatic heat exchanger at 40 degrees C and 250 kPa and exits at 240 degrees C. Superheated steam at 300...

When a valve on a pneumatic tire (filled with compressed air) is released and the tire is allowed to deflate, one may notice that the valve stem will become quite cold during the process. A common, everyday observation. So far, so good. The question is: What would we observe if the tire being...

An insulated cylinder of cross-sectional area .010m2 contains a monatomic ideal gas at T= 280 K. The system is in a vacuum chamber. Initally the gas supports the piston at a height of .20m. Sand is slowly placed onto the piston. When 10 kg of sand has been added, the piston has fallen .05m. How...

Two cylinders of equal volume are connected by a valve. We are given the pressure for one of them, and then told to find the final equilibrium pressure after the valve is opened. Adiabatic process may be assumed. I know the solution, but not sure why its that way... initially, I tried...

Here's my problem: 300 calories of heat are added to a gas as the internal energy of the gas increases by 500 calories. The described thermodynamic process is best described as? My guess is that the process is isothermal b/c work is being done in the system.

I was just wondering if there is a relationship between Pressure, Temperature , and Volume like there is for Ideal Gases, but for water. ie. for Ideal Gas: TV^(gamma-1) = constant PV^gamma = constant Any insight would be greatly appreciated, Thanks in advance.

How do you calculate the work done in an adiabatic process? I know change in thermal energy = work done. which amounts to (f/2)Nk(change in T). But how do you get change in T? Or is there another way to compute the work directly. The trouble is both the volume and temperture vary during...

Hey. Im doing this question where Air (said to be ideal gas) is compressed from a pressure of 0.1 MPa and Temp 300K to pressure .5 MPa and temperature 480K. We are supposed to determine whether the process is possible to do adiabatically (sorry if that is the wrong spelling). I hadnt done...

If I have two positive definite Hermitian NxN matrices A and B, if I adiabatically change the components of A to B (constraining any intermediate matrices to be Hermitian as well, but not necessarily positive definite) while \"following\" the eigenvalues ... will the mapping of the eigenvalues...

For a van der Waals gas experiencing an adiabatic process derive the following expression: T(V-nb)^(R/Cv) = Constant I tried using PV^gamma = Constant with gamma = Cp/Cv and Cp - Cv = nR with PV = nRT but could not get it. Any hints? I would have to use Boyle's law to account for...

During the compression stroke of a certain gasoline engine, the pressure increases from 1.00 atm to 20.3 atm. Assume that the process is adiabatic and the gas is ideal with (gamma)= 1.40. (a) By what factor does the volume change? Vfinal = (ans)*Vinitial (b) By what factor does...

All the places I've searched I find that the change in the internal energy for the adiabtic process is dU = C_V\,dT But I don't understand why they use C_V, neither the volume nor the preassure is constant during the adiabtic process.. I know that dU = C_V\,dT = C_p\,dT - p\,dV...

I'm reading a book on quontum mechanics in japanese (Quontum Mechanics by Shinichiro Tomonaga) and am stuck in proving the action variable "J" is constant in a one dimensional cyclic movement. i.e. The action variable "J" created by the trajectory of H(p(t),q(t),a(t/T)) = E(t) doesn't...