Equilibrium Definition and 1000 Threads

Thermodynamic equilibrium is an axiomatic concept of thermodynamics. It is an internal state of a single thermodynamic system, or a relation between several thermodynamic systems connected by more or less permeable or impermeable walls. In thermodynamic equilibrium there are no net macroscopic flows of matter or of energy, either within a system or between systems.
In a system that is in its own state of internal thermodynamic equilibrium, no macroscopic change occurs.
Systems in mutual thermodynamic equilibrium are simultaneously in mutual thermal, mechanical, chemical, and radiative equilibria. Systems can be in one kind of mutual equilibrium, though not in others. In thermodynamic equilibrium, all kinds of equilibrium hold at once and indefinitely, until disturbed by a thermodynamic operation. In a macroscopic equilibrium, perfectly or almost perfectly balanced microscopic exchanges occur; this is the physical explanation of the notion of macroscopic equilibrium.
A thermodynamic system in a state of internal thermodynamic equilibrium has a spatially uniform temperature. Its intensive properties, other than temperature, may be driven to spatial inhomogeneity by an unchanging long-range force field imposed on it by its surroundings.
In systems that are at a state of non-equilibrium there are, by contrast, net flows of matter or energy. If such changes can be triggered to occur in a system in which they are not already occurring, the system is said to be in a meta-stable equilibrium.
Though not a widely named "law," it is an axiom of thermodynamics that there exist states of thermodynamic equilibrium. The second law of thermodynamics states that when a body of material starts from an equilibrium state, in which, portions of it are held at different states by more or less permeable or impermeable partitions, and a thermodynamic operation removes or makes the partitions more permeable and it is isolated, then it spontaneously reaches its own, new state of internal thermodynamic equilibrium, and this is accompanied by an increase in the sum of the entropies of the portions.

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  1. It's me

    Callen Thermodynamics 2.8-2 matter flow equilibrium

    Homework Statement A two component gaseous system has a fundamental equation of the form $$S=AU^{1/3} V^{1/3} N^{1/3} + \frac{BN_1N_2}{N}$$ where $$N=N_1+N_2$$ and A and B are positive constants. A closed cylinder of total volume 2V_0 is separated into two equal subvolumes by a rigid diathermal...
  2. X

    Why does the potential difference between two capacitors seek equilibrium?

    Suppose we have a circuit with two capacitors connected to each other, C1 and C2. C1 is charged and has a potential difference of 5 V (V1=5V), but C2 is not charged (V2=0) Apparently it is known that the potential difference of these two capacitors will want to reach equilibrium. So V1=V2...
  3. P

    Equilibrium of Beams: Understanding Forces and Reactions

    hello! I don't understand, what is the equation that we use in beams is it that forces 1,2,3 equal with the reactions at the two supporting points? or the torques are 1,2,3 equal with the reactions at the two supporting points? and how do we find the reactions at the supporting points? thanks!
  4. hdp12

    Problem Check: Equilibrium of Particles

    Homework Statement A continuous cable of total length 4 m is wrapped around the small pulleys at A, B, C, D. If each spring is stretched 300 mm, determine the mass m of each block. Neglect the weight of the pulleys and cords. The springs are unstretched when d=2 m. The Attempt at a Solution I...
  5. K

    Explanation of Iodine Equilibrium in immiscible solvents

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  6. R

    Balancing two rollers on a hill

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  7. S

    Shielding simulation and nuclide vector

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  8. A

    Pressure/Temperature mechanical equilibrium

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  9. B

    Equilibrium expressions and partial pressures

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  10. B

    Is the System at Equilibrium with Given Concentrations?

    Homework Statement Consider the following reaction: H2 + I2 → 2HI (all gases) At 740 K, this reaction has an equilibrium constant of 50. If, at 740 K, the concentration of hydrogen gas is 2 M, iodine gas is 3 M, and hydrogen iodide gas is 6 M: (A) the concentration of hydrogen iodide will...
  11. hdp12

    Equilibrium of a Particle: Determining Forces in Cables and F for a 4-kg Lamp

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  12. hdp12

    What is the weight of block D in this equilibrium of particles problem?

    Homework Statement Here is the problem that I am stuck on in my mechanics class. https://lh4.googleusercontent.com/ygXVjNfI4iP8xVpEjhxXZlWlDqg_VrM2gCVFLyomOVwWCfcLU78mIcPEc7hEzUqBoACIiQ=w1210-h506 Homework Equations F=-kx The Attempt at a Solution See the attached picture of my work...
  13. terryds

    Triangle Ladder equilibrium problem

    Homework Statement http://www.sumoware.com/images/temp/xzebnqpmgdnohmgo.png An isosceles-triangle-shaped ladder like the picture above, has a negligible mass. A man with mass m kg climb the ladder till the height is 3 meter (see picture above). Determine the tension of the link (at...
  14. M

    MHB Equilibrium Problem: Landscaping Business|Accounts & Maintaining 500

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  15. T

    Finding angle required for equilibrium on a slope

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  16. ChrisVer

    Equilibrium at Universe (possible?)

    How can Universe be at equilibrium when the FRW metric has no time-like Killing Vector?Request: Please, move this into Cosmology thread... :( Mistakenly I posted it in HEP
  17. C

    Finding Equilibrium in a Three-Pulley System

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  18. K

    Chemical Equilibrium and Le Chatelier's Principle

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  19. little neutrino

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  20. J

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  21. Tyrannosaurus_

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  22. C

    Equilibrium Force: Solving for Centre of Mass | Homework Statement

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  23. G

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  24. Shindo

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  25. B

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  26. S

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  27. gracy

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  28. D

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  29. M

    Is the Equilibrium Calculation for HI Correct?

    Kc1 = (5.8*2/5)^2 / (14/5)(1.4/5) = 6.865 6.865 = [HI]^2 / (45/253.8/100)(0.5/2/100) [HI] = 5.52x10^-3 M mass no of HI = [HI] x (126.9+1) x 100 = 70.6g is it correct? And how to do 3bii I GOT 3bi Kc2 = [HCl(g)]^2/ / Kc(1) [H2(g)] [Cl2(g)]
  30. nmsurobert

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    So you take some boiling water and drop a metal cube into it and the cube will reach the temp of the water. Or you leave some hot water out on a desk and the water will eventually become room temperature, right? Then why, in the summer time, does the inside of the car get way hotter than the...
  31. M

    Buffer solution + equilibrium + Organic compound

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  32. B

    Torque seesaw problem- rotational equilibrium

    Homework Statement A seesaw with a mass of 5 kg has one block of mass 10 kg two meters to the left of the fulcrum and another block 0.5 m to the right of the fulcrum. If the seesaw is in equilibrium, A. find the mass of the second block. B. find the force exerted by the fulcrum I have trouble...
  33. S

    Static Equilibrium: Homework Questions

    Homework Statement I have a question about the following question: Firstly, shouldn't there be a normal force for each hand (part a), but here they treat it as one normal force. Also in part b, why isn't the torque for Fn1h = 0? Since that is the pivot point, isn't the moment arm zero?
  34. M

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    Homework Statement Homework Equations After creating a FBD and analyzing the forces, I get the equation for the angle as ## tan \theta = \frac{k q^2}{m g r^2} ## The Attempt at a Solution [/B] I have tried to find a way to find the distance between the charges ## r ##, but the only way I...
  35. C

    How Much Load Can a 300-kg Beam Support Before Exceeding Strut Safety Limits?

    Homework Statement A uniform 300-kg, 6.0 M long, freely pivoted at P, as shown in the figure. The beam is supported in a horizontal position by a light strut, 5.0 M long, which is freely pivoted at Q and is loosely pinned to the beam at R. A load of mass is suspended from the end of the beam at...
  36. W

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    Consider a pendulum in it's balance point hanging from ceiling. It can swing in all the directions in the space. The pendulum can only swing in a sphere(the string can't bend). Now, is it possible to release the pendulum in a particular height and with a initial condition that in the first...
  37. O

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    Homework Statement Given: The friction between the block with mass 11kg and the wedge with mass 22kg is 0.48. The surface between the wedge with mass 22kg and the horizontal plane is smooth (without friction). The [A][/g] = 9.8m/[/2]. A Block is released on the incline plane (top side of...
  38. M

    Heat Capacity and Thermal Equilibrium

    Homework Statement A 3.50-kg block of iron initially at 8.00 × 10^2 K is placed on top of a 6.25-kg block of copper initially at 4.00 × 10^2 K. Assume the blocks are thermally insulated from their surroundings but not from each other and that they constitute a closed system. How much energy is...
  39. nomadreid

    Game theory -- Nash equilibrium

    Suppose we have a game, played in which Alice and Bob play mixed strategies: (sorry for the dots, but I don't know how to put a table or tab spacing in this text box) ..............Bob ..........Dove, prob q......Hawk, prob (1-q) ...Dove , prob p......(2,3).........(4,5) Alice ...Hawk, prob...
  40. N

    How Does Child Movement Affect Torque and Force Distribution on a Plank?

    Homework Statement A child of mass m is supported on a light plank by his parents, who exert the forces F1 and F2 as indicated. Find the forces required to keep the plank in static equilibrium. Use the right end of the planks as the axis of rotation. ( Answer: F1=(1/4)mg, F2=(3/4)mg )...
  41. M

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    Hello I got to thinking about temperature when i prepared a lecture for my high school class. For a monoatomic ideal gas the temperature is proportional with the average kinetic energy of the atoms. For a diatomc gas we also have rotational energy (vibrations assumed to be freezed out), and for...
  42. A

    Calculate CO2 for Water Equilibrium at pH 7.2

    Hi, I must calculate how much CO2 has to be removed from the water (pHs=7.2) to obtain equilibrium Given concentrations: HCO3-: 223 mg/L CO2: 60 mg/L pH: unknown SI: unknown What is meant by equilibrium? (ph=7?) Please advise how to tackle this problem
  43. E

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    Homework Statement The question are included in the picture that are uploaded. So i know that for these systems to be at equilibrium, the net force in the x and y-axis must equal to zero. I wanted to write in the question and the diagram but i don't know how else to put it. Homework Equations...
  44. M

    Finding Equilibrium concentrations with added solutes?

    HF(aq) ↔ H+ + F- Determine equilibirum concentrations with Initital concentrations and Kc. Kc = 7.2 x 10-4 [HF] = 1.00M [NaF] = 0.50M I understand how to do an ICE table and put together questions, but what do you do with [NaF] when it is not part of the chemical equation? How to I factor it...
  45. P

    Why catalysts affect forward and reverse reactions?

    Based on the very basic understanding on enzymes I have gained from Year 12 Biology and Chemistry, I don't undesrtand why the enzymes specific shape also helps the reverse reaction. I guess my trouble would be due to the simplified diagrams I've seen from Biology, where only the forward reaction...
  46. W

    Hydropower plant in equilibrium

    I am trying to set up an equation relating the mechanical energy in a hydropower plant to its electrical output. What I picture is the relation between the energy input from the moving water, to the rotational energy of the turbine to the electric output of the generator. I know I can calculate...
  47. C

    Find load to create equilibrium on a bar.

    Homework Statement A 6.0 m bar is supported by a fulcrum at 3.9 m from the left end. There are loads applied to each end of the bar. The load at the left end of the bar is 468 N. What load in Newton should be applied to the right end of the bar to create equilibrium? Homework Equations M=Fd...
  48. P

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  49. V

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  50. M

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