All Questions
Tagged with reversibility adiabatic
75 questions
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Whats the lowest energy substance reaches during adiabatic expansion of carnot engine? [closed]
In carnot engine we know the steps like first isothermal, than adiabatic, then reverse isothermal and adiabatic.
And we know that efficiency increase if the temperature of hot box(heat supllier) is ...
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3
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139
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Why is the entropy change for a system in irreversible transformations the same as in reversible transformations in some cases, not in other cases?
Generally, the entropy change for a closed system for an irreversible transformation is not the same in a closed system for a reversible transformation.
A clear counterexample is that of an adiabatic ...
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2
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Can two different points can be connected by multiple adiabatic curves?
I was watching this Thermodynamics lecture and I have a question on the 1st law. More exactly on how different adiabatic curves can connect the same initial and final states. See the diagram drawn at ...
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Entropy in irreversible adiabtic process
We know that,
$$dS=\dfrac{\delta Q_{rev}}{T}$$
If you have an irreversible adiabatic process between two thermodynamic equilibrium end states of a system, there exists no possible reversible adiabatic ...
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Why do we need an adiabatic expansion in the Carnot cycle? [duplicate]
As we know that 1st process is an reversible isothermal expansion during this the system is in quasi static equilibrium which helps in increasing the volume of the system but why does the second step ...
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Container divided by adiabatic wall with mass and friction: why is it a quasi-static process?
Thanks to the help of @ChetMiller, the following fact is essentially concluded in this thread. Consider a rigid, thermally isolated container divided by a massless barrier parallel to its base into ...
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Container divided by frictionless adiabatic wall: reversible or irreversible process?
I have encountered an issue in the following physical situation. Consider a rigid, thermally insulated container divided by a barrier parallel to its base into two parts, left and right, each ...
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2
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Reversibility of the ideal Carnot cycle
How do adiabatic processes in the reversible Carnot cycle take place? Is the gas adiabatically isolated? If so, how would that happen in real life? (I know that Carnot cycle is not practically ...
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The work and reversibility of an adiabadically stretched band
I currently working on this. More specifically I have a question about Problem 2.8 (solution on page 34 and exercise on page 25 of the pdf). I have 4 questions
1.
In the solution for b) the author ...
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Is there an equivalent of "adiabatic" for work (i.e. a workless transformation)?
In Fermi's Thermodynamics (1937), Chapter I, §1, he defines an isochore transformation as
a transformation during which the system performs no external work
He then discusses the case where the ...
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3
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Are there known conditions that ensure infinite slowness is reversible?
A system has a Hamiltonian that depends on a few external parameters $V,X_1,X_2...$.
$$H=H(V,X_1,X_2....).$$
We can assume the dependence is continuous enough. A process is in the limit of infinite ...
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Derive $ΔS = Nk\ln(V/V_0)$ using fundamental equations of thermodynamics [closed]
I am considering a system with an ideal gas undergoing an adiabatic expansion. The initial volume is $V_0$ and final is $V$.
From this, How do I derive $\Delta S = Nk\ln(V/V_0)$ using fundamental ...
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Why can't a heat engine have 100% efficiency?
Using the idea of isotherms and adiabats, I came up with the following argument to convince myself. First imagine the working gas within the system being heated along an isochore (hence all heat ...
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Why is the final temperature of irreversible adiabatic processes higher than that of reversible adiabatic processes?
Suppose an irreversible adiabatic expansion process and a reversible adiabatic expansion process are starting from the same initial state, say, P1V1. Now, let both of these processes have equal ...
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Understanding page 141 of Blundell’s Concepts in thermal physics
On this page (in the second edition), there is a figure containing two states A and B of a system:
There are two paths between A and B: one is an irreversible change, and the other is a reversible ...
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Why isn't the free expansion of a gas in an adiabatic container isentropic?
If you expand a gas adiabatically using a piston, the process is isentropic. However, if you simply remove the piston and let the gas expand freely, the process is now not isentropic. What makes these ...
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Proof of Caratheodory's theorem
Caratheodory's formulation of second law of thermodynamics, also referred to as Caratheodory's principle states
In any neighbourhood of any thermodynamic state $P$ there exist states which are ...
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Understanding the use of $d$ and $\partial$ in thermodynamics
It seems a hundred variations of this question have been asked, and it's difficult to find which of those questions relates to exactly what I'm asking. My apologies if exactly this question has ...
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What are the requirements to apply the Laplace Law in Thermodynamics ? Reversible and adiabatic, or just adiabatic?
The Laplace's Law in thermodynamics states that an adabatic reversible transformation of a perfect gas verifies the following identity :
$$
PV^{\gamma} = cte \qquad \left( \gamma = \frac{C_p}{C_v} \...
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Comparing the final pressures/volumes/temperatures of a reversible and irreversible adiabatic process
Consider $2$ ideal and identical gases $A$ and $B$ which are at the same initial state of ($P_1$,$V_1$,$T_1$).
$A$ is taken through a reversible adiabatic process and $B$ through an irreversible ...
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What is the type of system, if I have an opened container with hot water inside, but no heat input to the system?
I have a school project, where I am trying to generate electricity using TEG modules that are attached to an aluminium container that contains hot water. The container is opened and there is no heat ...
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Uniqueness of Irreversible and adiabatic processes in finite time
Let the external intensive and extensive "mechanical" variables be denoted by $Y_k, X_k$. These variables are well defined irrespective of the system is in equilibrium or not. For an ...
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Can adiabatic heat exchange between different temperatures ever be reversible?
I've been told, A volume 2X of Temperature 0.5*(T1+T2) is always at higher entropy than thermally insulated volumes, 'X' at T1, 'X' at T2 put together.
Let's take Sys1 (A volume 2X of Temperature 0.5*(...
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Why the irreversible work carried in an adiabatic condition never causes change in internal energy?
I saw the lecture of thermodynamics on the MIT opencourse ware . In that lecture , the professor said that change in internal energy in an adiabtic process is caused by only reversible work , and not ...
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Is this set up a reversible process and is the adiabatic equation of state applicable here?
I had this question in a recent test:
My teacher while discussing this question used the adiabatic equation of state PV^gamma=constant to solve for length L (options C and D). And used work energy ...
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Work done on system and surroundings in an irreversible adiabatic compression
In an adiabatic irreversible compression process, suppose the pressure $P_{ext}$ compresses the piston and does some work say 50J. (50J of energy is lost by surrounding).
Since the pressure $P_{int}$ ...
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Reversible adiabatic process insight
How can a reversible adiabatic process (theoretically) be brought about since the system is insulated? A $\mathrm dP$ change in pressure will lead to a $\mathrm dT$ change in temperature thus ...
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Is it always true that a non-adiabatic reversible process is an isothermal process?
In a Carnot Cycle, a reversible isothermal process is a non-adiabatic reversible process. Is it always true that a non-adiabatic reversible process is an isothermal process?
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Adiabatic expansion, irreversible, in a container?
I'm reading D. F. Lawden, Principles of Thermodynamics and Statistical Mechanics, and am trying to understand the first worked problem they have. Below is the ...
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Adiabatic free expansion (Joule expansion) needing a small explanation
My professor tries to demonstrate that adiabatic free expansion is an irreversible process:
for and adiabatic $Q=0$;
because the gas is expanding through vacuum W=0;
therefore $\Delta U=Q-W=0$
now ...
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Is the enthalpy change in a reversible adiabatic expansion of an ideal gas 0?
I would like to know what happens to the enthalpy in a reversible adiabatic expansion for an ideal gas. Will it be greater than or equal to zero?
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Adiabatic process and internal energy
My question concerns the connection between change in internal energy $dE = Q - W$ and the available work in an adiabatic process.
My understanding is, that in an adiabatic process ($Q=0$) the change ...
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Is a constant pressure adiabatic irreversible expansion possible?
We know that adiabatic law for an ideal gas is,
$$ PV^{\gamma} =C$$
the differential of this under constant pressure is,
$$ P \gamma V^{\gamma-1} dV = 0$$
Now, the pressure and volume can't be at all ...
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Examples of processes that are reversible isentropic but not adiabatic?
Since $ds=\frac{dq_{rev}}{T}$ for reversible processes it seems we can have reversible isentropic processes that are not adiabatic provided the temperature changes in such way that the sum of $\frac{...
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Entropy generation at the molecular level in a irreversible process
When we expand an gas irreversibly in an adiabatic process then there is intermolecular friction, but what exactly gets transferred to heat. I have read that the directed motion gets randomized. But ...
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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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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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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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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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Calculating final pressure in irreversible adiabatic compression
I am trying to solve the following question.
A gas is enclosed in a cylindrical can fitted with a piston. The walls of the can and the piston are adiabatic. The initial pressure, volume and ...
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Reversible vs. Irreversible Expansion
Suppose I have a gas in a piston expanding adiabatically against atmospheric pressure. If I do this reversibly, the final state is uniquely specified by the final volume $V_F$ of the gas.
What ...
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Why the entropy change is not zero in the irreversible adiabatic process?
Why the entropy change is not zero in the irreversible adiabatic process?
...while it is defined as the integral of the heat added to the system over its temperature.
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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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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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4
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Thermodynamic process "in thermal equilibrium with the surroundings"
"During this process, the system is always in thermal equilibrium with the surroundings."
Does this statement mean the process is adiabatic? I would say yes: since the temperature of both ...
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Maximum velocity of piston pushed by a gas on adiabatic irreversible expansion [closed]
I am currently studying for my country's IPhO selection process and thermodynamics has to be one of my favorites right now. However I came across a very odd problem that is making me revise a lot of ...
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2
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2
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188
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Can the ideal gas expand adiabatically and irreversely?
Suppose that the ideal gas is expanding adiabatically from the state $(P_1, V_1, T_1)$ to the state $(P_2, V_2, T_2)$
I think this process can be allowed to happen reversibly or irreversibly, but ...
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Entropy change in a reversible adiabatic expansion of ideal gas
Below is P-V curves of 1 mole of ideal gase for temperature 700K, 500K and 300K each.
Now I would like to calculate entropy change of the system along the path from (1) to (3), which is adiabatic ...
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Adiabatic reversible and irreversible process
If I have 2 gases $A$ and $B$ which are at an initial state ($P_1$,$V_1$,$T_1$), and one gas say $A$ is taken through a reversible adiabatic process and the other gas $B$ through an irreversible ...
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Why doesn't reversible adiabatic expansion generate heat?
In analogy to a compressed gas allowed to reversibly expand and do work, I've been thinking about the behavior of a compressed spring that is very slowly and incrementally relieved of its pressure. ...
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