What is Isochoric: Definition and 31 Discussions

An isochoric process, also called a constant-volume process, an isovolumetric process, or an isometric process, is a thermodynamic process during which the volume of the closed system undergoing such a process remains constant. An isochoric process is exemplified by the heating or the cooling of the contents of a sealed, inelastic container: The thermodynamic process is the addition or removal of heat; the isolation of the contents of the container establishes the closed system; and the inability of the container to deform imposes the constant-volume condition. The isochoric process here should be a quasi-static process.

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  1. R

    I Irreversible Isochoric Process in a Cycle

    Consider a reversible ideal gas cycle consisting of: 1. An isochoric heat addition, 2. An isothermal expansion to the initial pressure, and 3. An isobaric compression to the initial volume. What, if any, is the difference in net work done by the gas in the cycle if the isochoric heat addition...
  2. G

    Stirling cycle: Why neglect isochoric heat transfers?

    Hi. To prove that the Stirling cycle has Carnot efficiency, one needs to neglect the isochoric heat transfers. Sure they have the same absolute value (but different signs), but it's still heat energy lost to the cold reservoir during the isothermic compression.
  3. RMalt

    Isobaric and Isochoric Process Combined

    Homework Statement [/B] This is a very basic question. I have a cylinder filled with air having stops at a particular height . First part of the process is isobaric as piston is free to move and P is constant. When piston reaches stops this becomes isochoric process as volume is constant. So...
  4. D

    Temperature in the regulator valve of a cylinder

    Homework Statement There is a cylinder of oxygen connected to a valve (A) and then to connected to a regulatory valve. The volume of both valves and the pipes between them is Vr and can be disconsidered in regard to the cylinder's volume. The oxygen can be considered a perfect gas with...
  5. S

    Does efficiency always depend on reversibility of the engine?

    I'm confused on the efficiency of a Thermal engine in the case it is reversible or not reversible, in particular where the ideal gas follows isochoric or isobaric processes. Infact during isochoric and isobaric processes $$Q_{isochoric}=n c_v \Delta T$$ $$Q_{isobaric}=n c_p \Delta T$$ So the...
  6. S

    Internal energy in irr. process with molar heat not constant

    I'm a bit confused about the following situation. In a irreversible thermodynamics process the molar heat of an ideal gas changes according to a function of the temperature, say ##c_v=f(T)## (which also leads to ##c_p=R+f(T)##) and I'm asked to determine the heat exchanged during that process...
  7. S

    Can the work in a isochoric process be non zero?

    I came up with a doubt regarding isochoric irreversible processes. Is it always true that, for any isochoric process, reversible or not, the work exchanged by the system is zero and the heat exchanged is ##Q=\Delta U##? I'm asking this because, in a exercise on thermodynamics trasformations of...
  8. M

    Calculating Internal Energy Change: Path 2 of Carnot Cycle Question

    Homework Statement A gas is to be expanded from initial stage i to final stage f along either path 1 or path 2 on a p-V diagram. Path 1 consists of three steps: an isothermal expansion(work is 23J in magnitude), an adiabatic expansion(work is 35J in magnitude), and another isothermal expansion...
  9. M

    Isochoric depressurization of distilled water question

    If a volume of highly pressurized distilled water was rapidly de-pressurized, but kept the same volume, would the internal pressure within the volume dissipate by thermalization? If so, how much would the water heat up for say 5km beneath sea level to above sea level pressure? I'm thinking...
  10. D

    Can a thermodynamic heat engine include all these processes?

    Homework Statement Hi, I'm a new user and got this problem. Sorry to bother, but I couldn't find any relevant information from my Physics books.. The problem states: Build a heat engine using these processes: adiabatic, isothermal, isochoric and isothermal. The work-cycle of the engine must...
  11. P

    Isochoric Process with Unknown Ideal Gas

    I was assigned a problem in my Engineering Thermodynamics class as follows: Problem: An ideal gas in a rigid closed container undergoes isochoric heating from T1 = 27 C to T2 = 77 C. Initial gage pressure is 300 kPa, pressure of surroundings is 1 atm. Find the final gage pressure. The way to...
  12. Soho

    Temperature varying in vacuum chamber during pressure adjust

    Hello everybody, I am working on some tests on materials and structures in a vacuum chamber. I noted that during the final moments of the pressure rising (when I open the valve to let the air in), temperature sensors installed in the chamber record the temperature rising more than ten degrees...
  13. MexChemE

    Internal energy, enthelpy and heat capacity

    Hello PF! I have some questions regarding these concepts. First of all, are the following expressions valid for any case? i.e. any kind of process, like isochoric, isobaric. \Delta U = \int C_v \ dT \Delta H = \int C_p \ dT Or is the ΔU expression only valid when dV = 0, and ΔH when dP = 0...
  14. MexChemE

    Isobaric/isochoric (?) heating of an ideal gas

    Homework Statement Consider an ideal gas with C_V=6.76 \frac{cal}{mol \cdot K}. Calculate \Delta H and \Delta U when ten moles of this gas are heated from 273.15 K to 373.15 K. Homework Equations \Delta H = \Delta U + P\Delta V Q=n C_V \Delta T The Attempt at a Solution As I'm given the heat...
  15. J

    Adiabatic, Isothermal and Isochoric Processes

    Homework Statement An ideal gas with Cv = (5/2)R, and Υ = 1.40 undergoes an adiabatic expansion until it has a pressure of 1.0*10^5 Pa and a volume of 2.0m^3. It then undergoes an isothermal contraction of T=300K until it has a volume of 1.0m^3, and then undergoes an isochoric (constant...
  16. M

    Thermodynamics Isochoric process .

    Hi can please check my answer for this question : A certain Gas of volume 0.4 m3, pressure of 4.5 bar and temperature of 1300 C is heated to in a cylinder to 9 bar when the volume remains constant. Calculate ¨ (i) Temperature at the end of the process, ¨ (ii) the heat...
  17. W

    Entropy change in isochoric process

    Homework Statement Hi everyone In an isochoric process ( a solid heat body with T1 temp. connected with heat bath with T2 temp) we could calculate its entropy change(heat body) from dS = Cv/T dT and entropy change of heat bath from dS = dQ / T2, using dQ = Cv dT in 1st equation ( i...
  18. Y

    Monatomic gas, Isochoric Process.

    Homework Statement n = 1.46 moles of ideal gas are heated isochorically (at constant volume) from tepmerature To = 649 oC to temperature Tf = 1184 oC. Find: a) Work done on the system. b) Change in Internal Energy of the system. c) The total heat, Q, added or removed from the system...
  19. M

    Why ∆u=Cv ∆T for isochoric transformation of non-ideal gases?

    I simply report what I read: "For an ideal gas, but for every kind of transformation ∆u=Cv ∆T, while for every kind of material in the thermodynamic system, but only for isochoric transformation ∆u=Cv ∆T." Where does this second statement come from? Everything is clear about ideal gases, but I...
  20. K

    Cooling that is both Adiabatic and Isochoric - possible?

    I figure that it is possible for temperature to decline in a fixed volume system that is thermally insulated. The reason why is that, from what I understand, is that random kinetic energy may have angular momentum. If we were to subject a volume of such energy to a rotating force (torque), then...
  21. T

    Thermodynamics - Internal Energy in Isochoric and Isobaric Processes

    Assuming that the gas in these processes is an ideal one, is the change in internal energy in an isochoric process (volume remaining constant) the same as the change in internal energy of isobaric process (pressure remaining constant)? Mathematically I can derive that they're equivalent, but...
  22. G

    Isochoric Compression Explained

    hi in school we talked about a process called "isochoric compression". i do not really know what they mean by that, since the word" isochoric" refers to a process that has always constant volume, whereas "compression" makes me think of a change in volume. is there anybody who can explain this...
  23. S

    Calculating Final Pressure in Isochoric Thermo Process

    I'm trying to calculate the final pressure. I was given initial and final temperatures as well as initial pressure, expansitivy and isothermal bulk modulus. I was also told the volume is constant. Since volume is constant I figured dV=0 so in the formula dV=VβdT - VKdP it reduces to...
  24. S

    Thermodynamics - isochoric situation

    I'm trying to calculate the final pressure. I was given initial and final temperatures as well as initial pressure, expansitivy and isothermal bulk modulus. I was also told the volume is constant. Since volume is constant I figured dV=0 so in the formula dV=VβdT - VKdP it reduces to...
  25. A

    Isochoric Processes: What's the Story?

    I'm studying for my physics exam on thursday and an odd thought just struck me. It is easy to see where the names for isothermal and isobaric processes came from - iso being the latin for equal, thermal being to do with heat and baric being to do with pressure. However what about ischoric...
  26. C

    Process such as isobaric, isochoric, quasistatic, adiabatic

    Just say an ideal gas goes through process such as isobaric, isochoric, quasistatic, adiabatic etc, is there any special cases where entropy is conserved, or am i thinking enthalpy. Also how is enthalpy found in adiabatic processes?
  27. T

    Isobarric, Isochoric, Adiabatic cycles

    Homework Statement Ok, i have a cycle that goes from "a to b", via isobaric expansion, than from "b to c" vis isochoric decrease in pressure, and "c to a" via a adiabatic compression. Each occur under quasistatic conditions I just want to double check I've got the, changes in work, heat...
  28. D

    Isobaric, Isochoric, Isothermal, and Adiabatic Processes

    http://session.masteringphysics.com/problemAsset/1013990/12/1013990E.jpg Which of the following statements are true about the first half of this process, just going from state A to state F? Both T and U increase. W provides energy input. Q provides energy input. Q is larger (in...
  29. T

    Isochoric and Isobaric (Ch.15 problem #26 Wiley+)

    Homework Statement Chapter 15, Problem 26 The drawing refers to 5.30 mol of a monatomic ideal gas and shows a process that has four steps, two isobaric (A to B, C to D) and two isochoric (B to C, D to A). (a) What is the work done from A to B? (b) What is the heat added or removed from B to...
  30. P

    Isotherm, Isobaric, and Isochoric Problem

    Homework Statement One mole of a monatomic ideal gas has an initial pressure, volume, and temperature of Po, Vo, and 442 K, respectively. It undergoes an isothermal expansion that triples the volume of the gas. Then the gas undergoes an isobaric compression back to its original volume...
  31. G

    Discover the Isochoric Process: Calculating Temperature in a Sealed Tank

    A 3.00-L tank contains air at 3.00 atm and 20.0 C. The tank is sealed and cooled until the pressure is 1.00 . What is the temperature then in degrees Celsius? Assume that the volume of the tank is constant. P/T=const 3/20=1/T, T=6.67 C Why it's not right?