Entropy Definition and 999 Threads

What is the entropy of weak and strong force? Can we determine their entropy? If so, I would like to know the formula of determining this. Thanks:wink:

Is there any relations of S and F? If any, I would like to know what the equation of this relationship will be. Thanks:wink:

Hey all. I have a question regarding the solution to a question, both shown below (only part of the solution is shown). Specifically the line that states: H(Y|X) = H(Z|X). Why does this equality hold? Expanding and using the definition of entropy, I can see that for the above equality to hold...

Do systems further away from equilibrium increase entropy faster than a system with a high level of entropy and does this increase push the universe towards thermal equilibrium faster. Is there anything stopping the universe from reaching thermal equilibrium?

Every explanation of this I have read has been extremely poor. Imagine we have a MONATOMIC gas, with no internal degrees of freedom. The gas is confined to a box of volume V, and this volume is constant and is not allowed to increased upon adding heat energy. We add an infinitesimal amount...

Hi all, Just doing some thermo study and am stuck on a question. I am not sure where to start this Q as normally I am given a property at the exit..? Any help is appreciated.

Entropy has been described to me many different ways. Overall, I understand it as the measurement of randomness or disorder in a system. This doesn't make sense to me. It seems that it is a term made for humans. For example, if we knew all the information about every particle in the universe...

hi all, this is Entropy Rate Balance for Control Volumes. in the case of throttling process, .throttling process is irreversible process, so (S2- S1) must be greater than zero. what i want to know is to prove that (s2-s1) is greater than zero. Thank you in advance.

Homework Statement The evaporation enthalpy of Hg is ##59.3 kJmol^-1## at its boiling temperature ##356.6ºC##. Calculate: (a) the vaporization entropy of Hg at this temperature (b) the change in entropy of the surroundings and universe (c) the vaporization entropy of Hg at 400ºC.I was also...

Homework Statement I am suppose to calculate the relative entropy between two sets of data: Base set Set 1: A C G T 0 0 0 10 0 0 0 10 0 0 10 0 0 10 0 0 10 0 0 0 * * * * //Randomized 0 0 0 10 0 10 0...

Dear PF Forum, I have a question to ask, Can two celestial bodies orbiting each other eternally without external influence? Does this process need energy? Thanks for any answer Steven

We all know that in free expansion of gases under adiabatic condition and keeping the temperture constant ,we get that no work is done by the gas.Moreover since del(Q)=0, del(U)=0 according to first law of thermodynamics.But we get a increase of entropy by an amount Rln2.Now the question is that...

Homework Statement A vessel containing 500 g of water, at a starting temperature of 15.0 ◦C, is placed in a freezer at −10.0 ◦C, and left to freeze. (i) If the heat capacity of the vessel is negligible, show that the total entropy change for the system of the water and the inside of the...

I realize this question has arisen before in the following thread: https://www.physicsforums.com/threads/difference-between-heat-and-work.461711/ but I felt there may be more room for discussion. I feel that the nature of the effect of heat on physical systems is a rather deep one. If the flow...

Homework Statement 1kg of silver is heated by a large heat reservoir at 373 K from 273K. Calculate the change of entropy in: a) the silver b) the reservoir c) the universe. Homework Equations ΔS = ∫dQ/T The Attempt at a Solution calculating the change in the silver first ΔS = ∫dQ/T...

Imagine a maximum entropy information system: This system would hold meaningful information, not just random noise, but still be of maximum possible entropy in the sense that you could randomly change the order of the smallest bits of information in it without actually changing the overall...

Chestermiller submitted a new PF Insights post Understanding Entropy and the 2nd Law of Thermodynamics Continue reading the Original PF Insights Post.

http://arxiv.org/abs/1503.02981 Four-Dimensional Entropy from Three-Dimensional Gravity S. Carlip (Submitted on 10 Mar 2015) At the horizon of a black hole, the action of (3+1)-dimensional loop quantum gravity acquires a boundary term that is formally identical to an action for three-dimensional...

Homework Statement [/B] Problem: In order to simplify your analysis, you will assume alcohol has the same properties of water so you can use the steam tables. You load the 30 gallon still 1/3 full with nearby water at 1 bar and 20°C and mash(assume the mash has negligible influence on...

Hi all Why the entropy increase across the stock wave.? How we can explain it Thanks

Homework Statement The question is says: Two vessels divided by a partition contain 1 mol of N2 and 2 mol of O2 gas. If the partition is removed and gases ate mixed isothermally, then find the change in entropy due to mixing assuming initial and final pressure are same . Homework Equations...

Homework Statement The question says: In a process involving n moles of an ideal gas , what is the entropy change of the system ? Homework Equations ΔS=qrev/T=(ΔU-w)/T (I have used the chemistry's equation of 1st law of thermodynamics which has the -ve sign) The Attempt at a Solution The...

Homework Statement There is a line in a question: "Entropy of an isolated system is always maximised at equilibrium." And it is given true. But Why? Homework Equations None The Attempt at a Solution In an isolated system heat input is equal to zero. And we know that entropy= heat...

Homework Statement Consider ##n## moles of gas, initially confined within a volume ##V## and held at temperature ##T##. The gas is expanded to a total volume ##\alpha V##, where ##\alpha## is a constant, by a reversible isothermal expansion. Assume that the gas obeys the van der Waals equation...

Homework Statement It is given in my book that: ΔStotal=ΔSsystem+ΔSsurrounding Where S is entropy. ΔSsurr=-ΔH/T Therefore: ΔStotal=ΔSsystem+[-ΔHsystem/T] As we can see here that ΔSsurrounding=-ΔHsystem/T is applied here . But is this relation correct? Homework Equations ΔS=qreversible/T Where...

The main result of thermodynamics is that if you have a place that is hot and another place that is colder, you can operate a heat engine by absorbing heat from the hot place and dumping it in the cold place, extracting some useful work in the process. It gives you a way to calculate the...

I'm taking thermal physics this semester and I have two questions that have been floating around my head, 1. Time's arrow and second law: If I have system (box of gas) and at t_i I know all the positions and momenta of all the particles, let's assume it's not in a state with maximum entropy...

Is there agreement here regarding the relationship between expansion of the universe from its initial conditions, entropy (2nd law), time, (and more tenuously perhaps) "evolution"? I asked a question awhile back that was too specific I think that tried to tie the constant of expansion to the...

Let's say we have two samples of pure Helium-4, and two other samples of pure hydrogen fluoride (consisting of Hydrogen-1 and Fluorine-19) all in separate containers. One container of each chemical is at the same initial temperature of 200°C at a pressure of 101kPa, and the other ones are at...

Homework Statement Planck famously argued that if identical particles are considered indistinguishable this would resolve Gibbs paradox by correcting for over-counting of the states. If the number of possible arrangements, W, of the N particles of an ideal gas at volume, V, and temperatureT...

I have a few questions about entropy and path Scenario I have a closed system of Ideal Gas- Volume is Fixed , Mol Vol is fixed. At room temperature the system is in thermal equilibrium with its surroundings I then cool this system removing Q . To this system I then re-add Q until it is again in...

I know that a black hole sucks stuff into a singularity, and I know about the second law of thermodynamics (that the entropy in an isolated system can only stay the same or increase), so if a black hole sucks something in it reduces the total entropy of the Universe, right? This was brought up...

Hello everybody, For my thermodynamics test I have to tell whether or not a quantity is a state function, which is obviously not all too difficult when regarding entropy, enthalpy etc. on their own. However there are a lot of questions where it is about "H-S" or "G-H". Are these not always...

Homework Statement 5 kg of water at 60 degrees are put in contact with 1 kg of ice at 0 degrees and are thermally isolated from everything else. The latent heat of ice is 3.3x105 J/kg What is the change of entropy of the universe when 100J of energy are transferred from the water to the ice...

One hundred 1:00 kg bricks are removed from a ring kiln, which operates at a temperature of 500 C; and are allowed to cool in the atmosphere at 20:0 C: If the process irreversibility is 18:8 MJ determine the entropy change of the Universe and the specic heat capacity of the material from which...

Penrose wrote in the Road to Reality that gravitational clumping increases the entropy of the universe. The early universe was very low in entropy because it was very smooth, with very little clumping. So, is it accurate to say that the early universe was high in entropy except for the...

Note: This is a question on a particular cosmological scheme, mainly Conformal Cyclic Cosmology. In Cycles of Time, Penrose says that Black Hole Information Loss causes the entropy to decrease in a way that doesn't violate the 2nd law. I think his analysis is correct, IF it was the case that...

Perhaps aptly, the subject of entropy is a serious mess when one attempts to use Prof. Google to learn about it. There's just too many disparate concepts across too many different domains for me to be able to piece it all together. With the baseline that I've learned the simplified...

Does the universe as a whole ever change from being the universe as a whole? Does it ever break into pieces and cease being the universe? And if anything (like the universe) never changed its state, wouldn't that mean its entropy never changed? Are there any constant thermodynamic properties...

Homework Statement A system is made up of two halves. In one there's 10kg neon gas with the temperature ##20 \circ##C, in the other 10kg nitrogen gas with the temperature ##100 \circ## C. Suppose the septum is removed so that thermodynamic equilibrium may appear and the gases mix. Calculate...

Today in my thermodynamics class my professor spoke about how a process must satisfy the laws of thermodynamics in order to work. He gave an example of current going through a wire generating heat. (See attached picture) But he also talked about how adding heat to a wire and it generating a...

Does entropy increase during spontaneous emission? If not, how is the information about the emitted photon mode encoded into the initial state of the atom (and/or environment)? If so, where does the extra information come from?

The equation for entropy S=delta(Q)/T is derived from reversible processes such as Carnot cycle. The delta(Q) in the equation is the reversible heat added or taken out from the system. So, why is this equation valid in the case of processes like cooling of a body which is irreversible?

Does "Entropy" play a role in Quantum Physics?

A lot of the less maths-y definitions of entropy talk about disorder and how disordered a system is. I'm given to understand that entropy is a measure of energy over temperate. Could someone clear up these misconceptions? I don't understand why 'disorder' is used. Isn't that subjective? Second...

Homework Statement A thermally conducting, uniform and homogeneous bar of length L, cross section A, density p and specific heat at constant pressure cp is brought to a nonuniform temperature distribution by contact at one end with a hot reservoir at a temperature TH and at the other end with a...

In Bojowald's 2010 popularization of Loop Quantum Cosmology Once Before Time, there's a sketchy diagram (on his p.125) showing quantum perturbations in a transitional phase between contracting and expanding universes as widest at earlier times of decreasing volume, narrowing at the...

just working my way through Susskind's "Theoretical Minimum". At the Langrangian formalism I'm in novel territory so this may be a dumb question. Kind of multiple choice or fill in a real answer. Why is there no term for the Entropy of a system in the Lagrangian? Is it because time is an...

Homework Statement 10 moles of an ideal gas Cv = 20.8 J/mol at T0 = 300 K and P0 =0.3 MPa occupy the left half of an insulated vessel. At time t=0 a 1 kW electrical heating element is turned on. after 30 s, the partition dividing the vessel ruptures and the heating element is turned off...

Homework Statement Determine ΔSsys when 3.0 mol of an ideal gas at 25°C and 1 atm is heatedd to 125°C and expanded to 5 atm. Rationalize the sign of ΔSsys. Homework Equations State Function: dS = (dU)/T + (PdV)/T State Function for Entropy of Ideal Gas: dS = (CV,mdT)/T + (nRdV)/V Ideal gas...