Questions tagged [adiabatic]

Thermodynamic processes that occur without exchanging heat between the system and its environment.

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Is it possible to increase the temperature of an ideal gas in an adiabatic sealed container with a frictionless piston for a lid?

As far as I understand it, if I pumped the piston repeatedly, compressing the gas, the temperature would go up for a second, but the minute I released the piston the higher pressure inside the ...
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How to calculate work for irreversible adiabatic processes?

By the first law, we know $\text{d}U=\delta Q+\delta W$ and, on adiabats, we know $\text{d} U=\delta W$. But what is $\delta W$ for irreversible adiabatic processes? Take a thermally isolated ...
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Can the internal energy - work exchange take place in an isolated system

Isolated System is a system through which neither mass nor energy can pass. According to this definition, could it be implied that although we could have no energy exchange, we can exchange Internal ...
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How is the Hamiltonian changed in Adiabatic Quantum computing?

In adiabatic quantum computing, we define a time-dependent Hamiltonian, which is then changed gradually to obtain a solution to an optimization problem. Is the Hamiltonian changed automatically, or we ...
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Why does the reversible adiabatic expansion do more work on the surroundings compared to the irreversible adiabatic expansion?

I am wondering why a reversible adiabatic expansion results in a higher work output on the surroundings though the irreversible adiabatic expansion has to overcome the frictional force and therefore, ...
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Formula for molar specific heat capacity in polytropic process

I found this formula for a polytropic process, defined by $PV^n = {\rm constant}$, in a book: $$C = \frac R{\gamma-1} + \frac R{1-n} $$ where $C$ is molar specific heat and $\gamma$ is adiabatic ...
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What is the adiabatic index of stiff matter?

In relativity, "stiff matter" is described by the relation $p = \rho$, where $p$ is the fluid's pressure and $\rho$ is its total energy density. The sound velocity in stiff matter equals the velocity ...
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622 views

Adiabatic closed system work

The closed system work PdV is path dependent but it is path independent for an adiabatic process as can be shown by applying conservation of energy on a closed system (dQ = dE + PdV),here dE is change ...
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Entropy change in the free expansion of a gas

Consider the adiabatic free expansion of a gas since there is no external Pressure hence Work done on the system is 0 and since the walls are insulated (hence adiabatic) the heat absorbed is 0. ...
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51 views

Internal energy change in isothermal process vs. adiabatic process with $\gamma$ approaching 1

This might be a somewhat academic question (since there's no gas with $\gamma = 1$), but I am still interested in this. Let's consider ideal gas and polytropic process with index $n$. We know, that ...
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Why only isothermal and adiabatic for Carnot engine?

What is the reason behind choosing adiabatic and isothermal process for carnot engine? My book states the following reason. I am not able to understand it. It would be great if you could put it in ...
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Internal energy of a reversible adiabatic process

what happens to the heat transfer and the internal energy in a system that undergoes reversible adiabatic process back to its original state. Bearing in mind that heat $Q$ was transferred at the ...
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Adiabatic Invariant for nonoscillatory system

For oscillatory system (e.g. quantum harmonic oscillation with slowly changing effective spring constant), it is common to define the adiabatic invariant to be $$I=\frac{H(t)}{\omega(t)}$$ where $H$ ...
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Work done in isothermal vs adiabatic process

If we include the sign then work done in adiabatic expansion as well as contraction is greater than the work done in isothermal process (as although area under $pV$ curve for isothermal process is ...
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On the way adiabatic processes were defined in Blundell's Concepts in Thermal Physics

In Blundell's Concepts in Thermal Physics, page $117$, the author defines an adiabatic expansion as follows, The word adiathermal means ‘without flow of heat’. A system bounded by adiathermal walls ...
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Adiabatic free expansion of real (Van der Waal's model) gas below/at/above inversion temperature

For free expansion, $W = 0$ And for an adiabatic process, $\Delta Q = 0$ Therefore, by the equation of the first law of thermodynamics, $\Delta U = 0$ For the Van der Waal model of a real gas, $\...
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Work done by adiabatic pumping ideal gas between two vessels

Lets consider I have two vessels of the same volume $V$ each of which contains ideal gas at different pressures and temperatures $(p_1,T_1)$, $(p_2,T_2)$. I pump certain amount of the gas $ n_\Delta$ ...
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Is there relation between adiabatic process and electron degeneracy pressure?

Electron degeneracy pressure scales with density as: eq.1.1: $p \approx \rho^{5/3}$ By dividing electron degeneracy pressures of 1 mole of electrons at two different densities we obtain: eq.1.2 ...
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Plotting isothermals and adiabats

first time poster in this site. I am trying to create a small program to make a graph of the Carnot cycle. For isothermals I am simply trying to look for points where P*V would give the same ...
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Adiabatic process and 2nd law violation

Consider a gas which expands adiabatically and reversibly. Since there is no heat in the process, the gas transform some of it's internal energy into work. As no entropy is exchanged or created, the ...
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Basic Thermodynamics: Quasistatic Adiabatic Process

I'm going through the exercises in a Thermodynamics book, just to revise and build my intuition. Right now, I'm working on: Show that for a quasistatic adiabatic process in a perfect gas, with ...
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Dry adiabatic lapse rate

Adiabatic lapse rate is defined as $$ \Gamma_a \equiv -\left(\frac{dT}{dz}\right)_{\rm parcel}=-\frac{R_{\rm a} T}{c_p \,p}\left(\frac{dp}{dz}\right)_{\rm parcel} = \frac{g}{c_p} $$ $R_a$ is gas ...
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Does “IF isentropic THEN reversible” only holds for adiabatic processes?

I know that: IF adiabatic and reversible THEN isentropic First question: does the implication IF isentropic THEN reversible hold for adiabatic processes? Second Question: if yes to the above, are ...
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Isothermal and Adiabatic Compression in the Carnot Cycle

I am reading about the Carnot Engine and I understood the first 2 stages (Isothermal and Adiabatic Expansion) well. In the 3rd stage where isothermal compression takes place, the surroundings do work ...
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Adiabatic compression of liquid water and vapor in equilibrium [closed]

I'm trying to solve Exercise 6.16 in Garrod's Statistical Mechanics and Thermodynamics. Here is what I've noticed so far. Since $V=n_lV_l+n_gV_g$ where $n_{(\cdot)}, V_{(\cdot)}$ are molar ...
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What is quasi-static process?

What is the formal definition of quasi static process? I am accustomed with it a bit intuitively, i want to know the formal definition of this. At some source I found the definition of somewhat ...
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The notion of an adiabatic process in thermodynamics -vs- quantum mechanics

I'm confused about the terminology in the two contexts since I can't figure out if they have a similar motivation. Afaik, the definitions state that quantum processes should be very slow to be called ...
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Saturation Conditions and Quality of CO2 at Exit of Tube

I'm stuck on what feels like a simple thermodynamics problem! I was hoping you might be able to shed some light. I've made a PDF with a detailed write up here: (updated doc with partial answer: https:...
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About an adiabatic stroke in the Carnot cycle

In one of the adiabatic stroke in the Carnot cycle, the temperature of the gas reduces from T1(to what it was initially heated) to T2(temperature of the surrounding). How exactly does the internal ...
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Related to the Second Law

It is impossible to cross two adiabatic curves. Could someone better justify me why? Is it something related to the Second Law?
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Equation for reversible adiabatic expansion

The heat capacity of one mole of an ideal gas is found to be $C_{v}=3R(1+aRT)/2$ where $a$ is a constant. The book provides the solution to this problem but there is a step in which $(1+aRT)=e^{aRt}$ ...
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Adiabatic volume change of an ideal gas thought process

I am struggling with trying to solve the following problem, attempting just (a) and the first part of (b) for this exercise: During a reversible adiabatic volume change of an ideal gas, $PV^{\gamma}...
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Thermodynamics adiabatic transformation

I have the following question as howework, I think I don't have enough information to solve it. Given are $p_1=311$ kN/m$^2$, $T_1=333$ K, $T_2=853$ K. Asked are $p_2$, ratio $V_1/V_2$, and $R$ if ...
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In adiabatic expansion does the internal energy of an ideal gas decrease?

By First Law of thermodynamic, for an ideal gas, if there isn’t heat transfer, work done by the gas is equal to decrease in internal energy of the gas. Suppose that I have a perfectly-insulated ...
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Two gases seperated by semi-permeable membrane

The problem is as follows: Two ideal gases are contained adiabatically and separated by an insulating, fixed piston that blocks the molecules of gas 2 but allows the molecules of gas 1 through(in both ...
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675 views

Thermal expansion of solid body and calculation of work produced

From the information about thermal expansion on Wikipedia, I found that if I heat a steel rod that's 1-meter in length and 1-cm in diameter steel rod to 100 degrees Celsius, then it will expand by ...
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Why can't adiabatic changes decrease entropy for a closed system?

I read that adiabatic changes in a closed system can never decrease the entropy. To try to understand why, I thought of two scenerios: reversible processes, and irreversible processes. For a ...
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Why is $PV^\gamma$ constant in an adiabatic process?

In non isolated systems where there is no adiabatic process, $PV$ is constant. But the graph gets steeper in adiabatic process because of the $\gamma$ over the $V$. Why is it there in adiabatic ...
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Is there a wall that can be regarded as an adiabatic wall?

I want to do thermodynamic experiments and need a wall that is approximately adiabatic. Does such a wall exist?
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How do you calculate the change in temperature of an adiabatic system? [closed]

I really don't even know how to start doing this problem. I understand PV=nRT and I understand that if either T, V, or P is kept constant, then the other 2 change at the same rate, and I understand ...
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Adiabatic filling of a container

Suppose a thermally insulated container is filled with atmospheric air until the pressure reaches 5000 psi. This could represent the filling of a diving cylinder, before thermal dissipation becomes ...
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When is total pressure not conserved in a system?

I came across a problem that involved two compartments that are separated by a movable, adiabatic wall. As the wall moves, the pressure is not conserved- rather total pressure decreases- assuming this ...
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How much steam must a planets atmosphere hold for no condensation to occur at bottom?

If a planets atmosphere contains steam how much would be required in order to have a temperature at the bottom, due to the adiabatic temperature gradient, to prevent condensation and thus rain in the ...
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Free adiabatic expansion is REVERSIBLE. Spot the mistake in this argument

So I know for a fact that free adiabatic expansion is irreversible. I thought of the following argument which shows that free adiabatic expansion is reversible and I wanted to know where's the mistake ...
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When is the adiabatic approximation for solid state systems valid?

The adiabatic approximation for solid state systems is rather radical. I was wondering in which cases it breaks down. As it is based on the idea of the nuclii being much heavier than the electrons I ...
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Restriction on the value of adiabatic exponent

My instructor stated in his lecture that the maximum value of the adiabatic exponent, $\gamma$, can be 5/3 which is that of a monoatomic gas and that it cannot go below 1, but why is this so? He also ...
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The transversality axiom in Lieb's Thermodynamics paper

I'm reading The Physics and Mathematics of the Second Law of Thermodynamics and have a question about the T4 transversality axiom which is writtern on page 54. T4) Transversality. if $\Gamma$ is ...
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First order wave function in adiabatic approximation

If the Hamiltonian is slowly varying in time and suppose the initial state is the n-th eigenstate of the initial Hamiltonian H(0), the adiabatic theorem says that the state will still on the n-th ...
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Work done in adiabatic reversible process

I was solving a problem on turbine.the steam works on turbine adiabatic reversibly .Is change in enthalpy or is it change in internal energy which equal this work?
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Adiabata for Van der Waals equation

Adiabata for ideal gas has equation $pV^\gamma = const.$ this allows calculate $p(V) = K/V^\gamma$, where K is some constant. Is there similar equation and preferably function $p(V)$ for gas ...

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