Reversible Definition and 240 Threads

For a closed system: If we define a quasi-static locus (process) as an ordered and dense succession of equilibrium states in the thermodynamic configuration space. Then we define a reversible process as one in which no entropy is generated. Then it is clear that there are some quasi-static loci...

I was reading Cengel's thermodynamics and noticed that he uses a thought experiment to show that there is no machine that is more efficient than the Carnot reversible machine. He says that both a reversible machine and an irreversible machine are connected to high and low temperature deposits...

Is is possible to have 2 different engines with all the following criterion? 1) Are reversible 2) Work differently (different cycles) 3) At the same working temepratures have different efficiencies. E.g. Working temperatures 100K and 50K. Engine 1: Carnot's Efficiency - 50%...

I am studying Reif's Fundamental of Statistical and Thermal Physics. (p.91) he explain about Reversible and Irreversible processes by using "The number of accessible states in equilibrium(Ω)". in his point of view, each accessible states have equal probability. comparing to weather...

Hello guys, first post in this forum :) Magnetism has always been complicated to understand for me, and I would like some help regarding Curie temperatures. We have just bought a new measurement equipment to out lab which shall be temperature calibrated with curiepoints. We have three...

Please find the attachment and comment about equation (2).

Hello, It is said that any process accompanied by dissipating effects is an irreversible process.For instance, a piston cylinder arrangement undergoing an expansion of a gas with heat lost as friction between surfaces is an irreversible process.Here the system does work on the...

Imagine a rigid block of steel at 100 degrees celsius which is inserted into water at 0 degrees celsius. They then both get an equilibrium temperature. How can I tell whether this is a reversible or irreversible process? What is the argumentation?

Homework Statement Homework Equations The Attempt at a Solution I can do everything else except work for part one going from A to B. What I did was -∫PdV = -nRT ∫(1/v)dV = -nRT ln (Vf/Vi) I can solve for T because everything is given, T in Kelvin is 882. From PV=nRT T=(5atm)(10L)/1mol*R...

Homework Statement The Clapeyron cycle efficiency is similar to the Carnot cycle except that two adiabatic paths are replaced with isobaric processes a) based on the above information, draw a Clapeyron cycle. b)Derive the efficiency of the reversible Clapeyron cycle Homework...

So my professor keeps bringing up that a reversible process must always be done infinitesimally slowly up. But why is that? I can't recall the explanation.

Hello everyone, I've been reviewing some concepts on Thermodynamics and, even though I feel like I am gaining a level of comprehension about the subject that I could not have achieved before as an undergraduate, I am also running into some situations in which some thermodynamic concepts seem to...

I'm working from Callen ch. 4: Consider a monatomic ideal gas in a cylinder fitted with a piston.The walls of the cylinder and the piston are adiabatic. The system is initially in equilibrium, but the external pressure is slowly decreased. The energy change of the gas in the resultant...

I know that ΔS=qrev/T for any process, but what is qrev here? It can't be identical to the q in ΔU=q+w - if it was, why don't we just write it q? The other problem is that it would mean that ΔS(surroundings)=-ΔS(system) which need not always be true. Secondly I want to derive the equation for...

∫dQ/T≤∫dQ(rev)/T * , where both integrals are evaluated between the same thermodynamic coordinates- A and B , say. - I am having trouble interpreting this inequality. -( I understand the derivation in my textbook via the Clausius diagram(considering a reversible and an ireversible process...

I've got a couple of questions about reversible cycles: So if we have two gaseous systems and have a reversible cycle working between them, then the entropy generation within each gaseous system is zero, right? Do turbines execute reversible cycles? Thanks a lot for your help!

Homework Statement A sample of carbon dioxide, mass 2.45g, is allowed to expand reversible & adiabaticly from 500cm3 to 3.00 dm3 What is the work done by the gas Homework Equations dw=-pexdV du=dq+dw du=nCv,mdt The Attempt at a Solution At first i just wanted to say that because...

There are 2 types of reactions 1) Being fully irreversible and 2) reversible So for 1) the graph of Gibbs energy against the progress of reaction would look like this: http://postimg.org/image/phycri0vr/ So the difference between 100% product and 100% reactant is the ΔG of the reaction...

1. An ideal heat engine (HE) is used to drive a reversible heat pump (HP) as shown in figure below. The HE takes in Q1 heat units at T1 and rejects Q2 at T2. The HP abstracts Q4 from the sink at T4 and discharges Q3 at T3. Develop an expression for the ratio Q4/Q1 in terms of...

I found an interesting paper here a two level system is measured by a harmonic oscillator(the apparatus). the apparatus is coupled to its environment, a bath of oscillators. The article shows how the reduced matrix of S+ A decoheres (the off diagonal elements tend to zero). I am looking for a...

Using A\widetilde{A}=(detA)I prove that \widetilde{A} is reversible matrix if and only if A is reversible. Also prove det(\widetilde{A})=(detA)^{n-1} for any square matrix A. First part: 1. direction: Lets say \widetilde{A} is reversible, this means that \widetilde{A}\widetilde{A}^{-1}=I...

In thermodynamics(at least in classical thermodynamics),the idealization of reversible processes is used time and again.Can we say it is central to thermodynamics? I mean can we say it is so important that if we can't find a reversible counterpart for an irreversible process,then the existence...

I have a cycle (and the gas is ideal) that starts at Pressure=4Po Volume=Vo and and Temperature=Th. First step it's cooled at constant volume to Tc and Po; Second step, it is reheated at constant pressure to Th and 4Vo, and lastly it is compressed at constant temperature to Vo and 4Po. For those...

I ask this because I've heard repeatedly that all the equations in current physics models are reversible in time, save the second law of thermodynamics. But does this mean the process of radioactive decay is also reversible in time?

∫Homework Statement Compress a body reversibly and isothermally from P1 to P2. How much heat goes in or out?Homework Equations Maxwells four relations, differential forms of the four thermodynamic potentials (Central, Enthalpy, Gibbs, Helmholtz) The Attempt at a Solution My problem is that...

I am trying to teach myself the basics of thermodynamics using a book I bought from a university book store. My question relates to the amount of work done by reversible vs irreversible processes. An example in the book (Chemical Principles by Atkins & Jones) reads the following: "A cylinder...

Stirling engine: the cycle is composed by two isothermals and 2 isometrica and there are just two heat reservoirs. By the isometrics I would say that that it is irreversible since you exchanging heat with a reservoir at a different temperature than your gas. However my notes say the...

I know carnot's cycle is an example. but what is it exactly? a cycle in which ever part of process has a 'counter-process' please elaborate.

Homework Statement A system containing 10kg of water undergoes a reversible isothermal process. The initial state can be characterized as saturated vapor at 300°C. The pressure in the final state is 1MPa. The heat transfer during the process in (inKJ) Homework Equations Q = m(U2-U1)+W...

Hi I'm having a very hard time trying to picture an argument in Feynmans physics volume one ). I can't picture this example he is talking about, so I wrote it down from the book and really hope someone can help me answer the question in the bottom. From the book (everything needed to know...

Heat is defined as "the transfer of energy owing to a temperature difference between two bodies". Consider a gas expanding against a massless frictionless piston. Assume that the process is both isothermal and reversible, and that the gas is ideal, so that its internal energy does not change...

For a reversible process, I imagine it is correct to say that dS = \frac{dq}{T} where all quantities refer to system quantities (not the surrounding). However, for an adiabatic process, dq = 0 . Thus, should it be the case that for an adiabatic reversible process, dS =...

Homework Statement Show that in a reversible adiabatic process, for 1 mole of ideal gas P1V1γ=P2V2γ Where, γ=CP/CVHomework Equations Listed above.The Attempt at a Solution Frankly, I don't really understand what I'm being asked to do.

Homework Statement a fluid undergoes a reversible adiabatic compression from .5 MPa, .2 m3 to .05 m3 according to the law PV1.3 = constant. determine the change in enthalpy, internal energy and work transfer during the process. Homework Equations P1V11.3 = P2V21.3 dH = T dS + V dP dS = 0...

Please don't be harsh on me. I just heard of reversible equation and had this thought: Is it possible to separate reactants from equilibrium and then later use it for energy generation? Kind of like water evaporating and absorbing heat energy.

Homework Statement One mole of an ideal monatomic gas initially at volume Vi and temperature 1000k expands to a final volume Cvi in three reversible steps: 1) isothermal expansion from Vi to aVi, 2) adiabatic expansion from aVi to bVi and 3) isothermal expansion from bVi to Cvi In terms...

Is the statement Ke=k+/k- valid for all equilibrium constants like Ka, Kx, Kp, Kc? All of the expressions I have found for this statement relate Kc, k+ and k- only.

Are ALL ligand exchange reactions reversible? Therefore, if the Kstab of one complex is LESS than that of the other complex, would it ONLY be possible to form the LESS stable complex by 'flooding' the mixture with the appropriate ion. (these values are not real but they illustrate what I...

Homework Statement Ideal gas initially at temperature Ti, Pressure Pi, Volume Vi is compressed reversibly down to half its original volume. Temperature of gas is varied during the compression so that P = AV is always satisfied [where A is a constant] Show that the work done on the...

PROBLEM: One mole of an ideal monatomic gas initially at 300 K (T1) and a pressure of 15.0 atm (P1) expands to a final pressure of 1.00 atm (P2). The expansion occurs via an adiabatic and reversible path. Calculate q, w, ΔU, and ΔH. SOLUTION: q = 0 (adiabatic; no heat exchange occurs)...

Homework Statement Mercury is a silvery liquid at room temperature. The freezing point is -38.9 degrees celcius at atmospheric pressure and the enthalpy change when the mercury metls is 2.29 kJ/mol. Wat is the entropy change of the mercury if 50.0 g of mercury freezes at these conditions? The...

Homework Statement A system absorbs QH = 481 J of heat reversibly from a hot reservoir at temperature TH = 370 K, and gives off QC = 155.4 J of heat to a cold reservoir at TC = 156 K. During this process, W = 90.9 J of work is done by the system. a) Find ΔIE, the change in internal energy...

Homework Statement A real gas obeys Van der Waals‟ equation, which for one mole of gas is (p + A/V2)(V-B) = RT and its internal energy is given by U = CvT - A/V where the molar heat capacity at constant volume, Cv , is independent of the temperature and pressure. Show that the relation...

consider we have a map. what condition should have our map that it has inverse?

Although I've read many times that quantum computers are reversible, I am unable to find a understandable explanation as to why (this may be because I study Computer Science). From what I've read, I assume that the answer is linked to the Second Law of Thermodynamics, but I don't know how...

Hi all, I've been having some difficulty understanding the derivation of the Fundamental Theorem of Thermodynamics, dU=T \ dS-P \ dV. The derivation, which can be found at Wikipedia (http://en.wikipedia.org/wiki/Fundamental_thermodynamic_relation) first starts with the universal First Law...

hi .i am new here i like to know if this motor can't reversed using a switch from turning right to left . i am a knifes maker [was] and my motor have to turn clock wise and counter clock . thank you . yvesj

Homework Statement A borehole produces 120kg/s of high pressure water at 165°C. A powerplant is to be designed to extract heat from the water, reducing the temp to 147°C. The plant which will initially be assumed to be reversible, will reject heat at 17°C to a river. Take 147°C as the highest...

I can only assume it is, if a Higgs can be found anyway. I learned about hysteresis in certain physical processes. I don't have the math to guess nor Google skills to find a clear answer. If it were, would a sufficiently large and hot enough black hole be in danger of losing its mass terms...

Homework Statement The motor that drives a reversible refrigerator produced 142 W of useful power. The hot and cold temperatures of the heat reservoirs are 20°C and -6.1°C. What is the maximum amount of ice that can produce in 2.2 hours from water that is initially at 6.0°C? Homework...