Adiabatic Definition and 470 Threads

Hi, I was doing this question and I was slightly confused as to whether I ought to just substitute n = \gamma (the adiabatic constant) into the equation? The answers don't do this, but I was wondering why it was wrong for me to do so? This was only a small fraction of the question (which was...

Using (2) on (1) give ## dU = -dW##... (4) A.For expansion since the gas goes from ##(P_1, V_1, T_1)## to ##(P_2, V_2, T_2)##, does this imply ##T_1 \leq T_2 ##? B. If so, then ##W## for adiabatic expansion would be negative (using (3))? Using negative ##dW## in (4) gives us a positive result...

Hi, consider an adiabatic irreversible process carrying a thermodynamic system from initial state A to final state B: this process is accompanied by a positive change in system entropy (call it ##S_g##). Then consider a reversible process between the same initial and final system state. Such...

Homework Statement Here's a derivation of the adiabatic PVT relationships. QUESTION: When solving adiabatic PVT homework problems I found that I needed to express temperature in Kelvin, rather than Celsius, to get the right answers. Where in this derivation should this be specified, and how...

Homework Statement Given a problem where air expands adiabatically with a given initial temperature, initial pressure, final pressure, and gamma (ratio of specific heats) , how would one go about solving for the final temperature? I'm just eager to get a general sense of direction. Homework...

Homework Statement Question If changed isothermal compression process to adiabatic compression process. find the final temperature of process. Homework Equations ## \alpha = \frac{1}{v} (\frac{∂v}{∂T})_{P} ## expansivity ## \beta = -\frac{1}{v} (\frac{∂v}{∂P})_{T} ## compressibility...

I've seen the derivation for the adiabatic expansion of an ideal gas which gives the result ## TV^{\gamma - 1} = constant ## which I understand. I have also seen the a similar result, ## pV^{\gamma} = constant ##. But I can't see how to get from the first expression to the second. Any ideas?

Homework Statement An adiabatic isolated system is formed of three identical balloons (of unknown volume). The balloons are joined by tubes of negligible volume. Each tube has a faucet/tap that is initially closed. The balloons have different quantities of the same ideal gas. After opening...

Homework Statement Derive an expression for the change of temperature of a solid material that is compressed adiabatically and reversible in terms of physical quantities. (The second part of this problem is: The pressure on a block of iron is increased by 1000 atm adiabatically and...

Homework Statement [/B] An ideal gas is compressed to the same volume from the same initial state for both an adiabatic and an isothermal process. In which case will more work be done ? 2. Homework Equations ##dU=dQ - dW ## ##W=\int P\,dV ##(For isothermal) ##W=nc_vdT##...

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 Determine the ratio of the work that you must expend when a single-atom ideal Gas once isothermic and once adiabatic to 1/10 of its original volume is compressed. In both cases the initial pressure, initial volume and gas amount are all equal. The Attempt at a Solution Case...

Homework Statement Assume that Planck's constant is not actually constant, but is a slowly varying function of time, $$\hbar \rightarrow \hbar (t)$$ with $$\hbar (t) = \hbar_0 e^{- \lambda t}$$ Where ##\hbar_0## is the value of ##\hbar## at ##t = 0##. Consider the Hydrogen atom in this case...

Homework Statement Adiabatic expansion of an ideal gas is carried out in a steady flow process. The initial pressure of the gas is 2.5 bar. The volume is expanded from 1.2m3 to 3.8m3. Heat capacity ratio (γ) = 1.42. Calculate enthalpy change of the process. Homework Equations PV = nRT W = ∫...

Homework Statement The change in entropy is zero for: A. reversible adiabatic processes B. reversible isothermal processes C. reversible processes during which no work is done D. reversible isobaric processes E. all adiabatic processes Homework Equations ## dS = \frac{dQ}{T} ## The Attempt...

Many textbook, particularly Forster Resonance Energy Transfer shows a diagram where transition of a donor nonradiatively excites an acceptor in the dipole interaction scheme. When considering spectral overlap, they explain the overlap of the phonon-sidebands of the two species. This seems to me...

Consider the following problem: Gaseous helium (assumed ideal) filled in a horizontal cylindrical vessel is separated from its surroundings by a massless piston. Both piston and cylinder are thermally insulating. The ambient pressure is suddenly tripled without changing the ambient temperature...

Homework Statement The hydrostatic equation expresses the change in pressure dp due to a layer of atmosphere of thickness dz as constant volume. ##dp = −\rho g dz ## Using this expression, show that the change in temperature with height for a parcel of air that rises adiabatically in the...

Source: https://en.wikipedia.org/wiki/Irreversible_process I think I can see it mathematically but it is not very intuitive to me as it seems like there is creation of energy...

Homework Statement I do not know if I am allowed to have two question in one post, so forgive me if I am breaking a rule. These two are frustrating me as I cannot see where the error in my process is. 1) A 1.00-mol sample of an ideal diatomic gas, originally at 1.00 atm and 10 ∘C, expands...

Homework Statement A sample of 1.60 mol H2 (Cv = 20.5 J K-1 mol-1) at 21°C and 1.50 atm undergoes a reversible adiabatic compression until the final pressure is 4.50 atm. Calculate the final volume of the gas sample and the work associated with this process. Assume that the gas behaves ideally...

Homework Statement A container of 1.5 Kg of gas is at a temperature and pressure of 293 K and 1 bar respectively. The gas is adiabatically compressed until its temperature and pressure are 450 K, 4.49 bars. Adiabatic processes are processes with no heat transfer. The properties of this...

For an adiabatic process, Q = 0. From the first law of thermodynamic, ΔU = Q + W on the system when Q = 0, W = -PΔV, then why is it that ΔU = Cv ΔT when Cv is meant for the constant volume? We know that when there is work done, the volume is changing, and making use of Cv sounds like an...

Homework Statement A mixture of hydrogen, carbon monoxide and carbon dioxide is being fed to a compressor at 2.0 bar and 25 C. The overall flow rate is 17.47 SCMS and its composition is 73.5 mol% H2, 13.7 mol% CO and the balance CO2 The compressor operates adiabatically and reversibly with a...

How come ##adiabatic \,work = C_v(T_2 -T_1)##

Homework Statement For a stretched rubber band, it is observed experimentally that the tension ##f## is proportional to the temperature ##T## if the length ##L## is held constant. Prove that: (b) adiabatic stretching of the band results in an increase in temperature; (c) the band will...

Homework Statement An airgun shoots a ball made from lead, through air of high pressure that pushes the ballforward like a piston. Because this happens very quickly, Q = 0 and the process is adiabatic. The initial volume of the air is Vi = 12.0 cm3 = 12.0 * 10-6 m3, which behaves as an ideal...

Hello all. Firstly I am sorry if this is in the wrong place but I was unsure exactly where it fits in as it involves physics, integrated equations, and computer programming. I am trying to write an emulator for a machine which is running 256 filament lamps in a 16*16 matrix. I want to simulate...

Homework Statement . Consider a pump that is required to compress air in a factory. The cylinder in the pump has an inner diameter of 2.00 cm and length 60.0 cm. Air is drawn into the pump at atmospheric pressure and 18 degrees celcius and the pump adiabatically compresses the air to a pressure...

I'm reading a thermo book and I'm on the chapter dealing with the first law of thermodynamics. The book is discussing functions of state and how the internal energy is a function of state because it has a well defined value at every equilibrium state of the system. It says that the work and...

Hello.I have a question about entropy of a thermodynamic system. 1)If we have let say a gas that is separated by some thermo isolated walls (so no heat goes in or out) does the entropy of that gas conserve? I taught that if S=dQ/dt, because Q=0,then the entropy should be conserved. 2)So,does the...

Homework Statement Calculate changes in A and G of one mole of an ideal gas that undergoes the following processes respectively. 1. adiabatic expansion from (T1, P1) to (T2, P2) 2. isobaric expansion from (P, V1, T1) to (P, V2, T2) (if it is not isothermal) 3. isochoric expansion from (V, P1...

Homework Statement I'm stuck on part (c) of this question. Homework Equations $$T\frac{d}{dT}\bigg(\frac{L}{T}\bigg) \equiv \frac{dL}{dT} - \frac{L}{T}.$$ Clausius-Clapeyron equation: $$ \frac{dp}{dT} = \frac{L}{T\Delta V} \approx \frac{L}{TV_{vap}}.$$ The Attempt at a Solution My approach...

Hello everyone! I've been thinking a lot about this thermodynamics problem , hearing all sorts of opinions but never getting a full rigurous explanation. So we have a cylinder that is placed in vacuum. We insert in the cylinder a monoatomic ideal gas. The gas is trapped inside the cylinder with...

Homework Statement [/B] Find the final temperature, Q, ΔU, ΔH given the following Initial state of gas Ti = 353K Pi = 250000Pa 2.5mols of gas Cv = 12.47Jmol-1 Final pressure = 125000Pa Homework Equations PV = nRT W = -PΔV ΔH = ΔU + Δ(PV) PVγ = constant The Attempt at a Solution Cv / R ≈3/2...

I have been researching the Rankine cycle. I know that it consists of two adiabatic and two isobaric processes. However, I'm not entirely sure why we ignore the work done during the isobaric processes (this seems to be the case in the analysis I'm looking at). Is that because the work done there...

Homework Statement Assume 1.500 mol of a monatomic ideal gas is compressed from 3.00 L to 1.00 L. a. If the initial and final temperature is 10.0 °C, what are the initial and final pressures (in atm)? b. How much work input (in kJ) is required if a reversible isothermal path at 10.0 °C is...

"How it can be explained mathematically by dP/dV = -gammaP/V

Hello, I am currently trying to get my head around the concept of entropy. One way to understand it is that it can be related to the amount of available energy levels in a system. From what I read, the availability of energy levels in a system: 1) increase with an increase in the system...

I have a question I hope someone may be able to answer. I am currently working out an adiabatic compression process that gives me an initial pressure,volume, and temperature. Along with a final pressure and given that the cylinder/piston assembly does not conduct any heat. Another given is that...

Homework Statement Calculate the change in internal energy of an ideal gas the expands reverisbly and adiabatically from ##v_i## to ##v_f## Homework Equations ##pV^{\gamma} = constant ##*, where ##\gamma=\frac{c_p}{c_v}## for a reversible adiabatic. ##E=\alpha p V##, ##\alpha## a constant...

I have a dilemma, which has been nagging at me for a week. So first off, can anyone verify my definitions are correct? Heat is the flow of energy, and that flow is caused by the collisions of the atoms in a system. The collisions cause a transfer of KE, hence heat will flow from a substance...

A diabatic process is defined as follows: Rapidly changing conditions prevent the system from adapting its configuration during the process, hence the spatial probability density remains unchanged. Typically there is no eigenstate of the final Hamiltonian with the same functional form as the...

Homework Statement A turbine is driven by compressed air. The air enter the turbine with temperature ##T_1## and pressure ##P_1##. When the air leaves the turbine it's pressure is lowered to ##P_2##. Calculate the work done for one mol air. The expansion of the air can be seen as reversible...

Why does there tend to be disagreement on an irreversible adiabat entropy determination? Doesn't an irreversible adiabatic expansion increase the entropy of a system by the Clausius inequality?

How can a permeable piston be adiabatic? If substances can go in and out of the cylinder and the substances have heat energy, heat can be exchanged through a permeable piston. I came across this term in the book, but cannot understand.

Homework Statement Show that for a gas obeying the van der Waals equation ##\left(P+\frac{a}{v^2}\right)(v-b)=RT##, with ##c_v## a function of ##T## only, an equation for an adiabatic process is $$T(v-b)^{R/c_v}=constant$$ Homework Equations ##TdS=c_vdT+T\left(\frac{\partial P}{\partial...

In what follows I refer to the ideas of "Thermodynamic: Foundations and Applications" by Gyftoploulos and Beretta. The abbreviated form of my question is: In a reversible weight process, Ω1R-Ω2R = E1 - E2 (see eqn. 6.18, p. 99) is transferred out of the composite of a system A and a reservoir R...

Homework Statement An ideal monatomic gas has initial pressure Po and occupies initial volume Vo. The gas undergoes an adiabatic expansion in which the volume is doubled. Calculate in terms of Po and Vo a) the final pressure of the gas b) the change in its enthalpy during the...

I want to know if a specific amount of gas has been compressed isothermaly an then released to expand freely, how much of the energy that has been spent on compressing the gas can be recovered. As for example, 1 gm-mole of Nitrogen has been compressed to 1/4th of its initial volume from at 1...