Thermodynamic Definition and 459 Threads

Can someone give an example of how to compute the "thermodynamic limit" of some model? I am very confused by this concept.

Hi, after a while of searching through a thermodynamics book and not really finding what I'm looking for I come to you all with my problem :D Here it is: I am required to write a formula which will allow me to determine the outlet temperature of a pipe carrying water for any given flow...

I am looking for a liquid with a high thermal expansion coefficient. This liquid should act as a working fluid in an thermodynamic cycle based on a system where the working fluid act in the same phase (liquid phase) throughout the cycle. So far I have found pentane as one of the most...

If I have some arbitrary Thermodynamic system, and I want to find the equilibrium state what do I do? Lets say that I know Internal energy: U(S,V) Helmholtz free energy: F(T,V) Enthalpy: H(S,P) Gibbs free energy: G(T,P) (I omitted the dependence on particles N) I've been...

Homework Statement Initially, 0.745 moles of an ideal gas in a container occupies a volume of 3.55 L at a pressure of 3.82 atm with an internal energy of 1705 J. The gas is then cooled at a constant volume until its pressure is 2.06 atm. Then the gas is allowed to expand at a constant pressure...

1. One question ask "Which statement below regarding the First Law of Thermodynamics is best? Select the correct answer." One of the wrong answer is "A system can do work externally only if its internal energy decreases. " What does it mean do work externally? 2. Another question ask...

I have been wondering now for quite some time about the meaning of Euclidean Quantum Field Theory. The Wick rotation t\to it allows us to transform a QFT in Minkowski space to a QFT in Euclidean space (positive definite metric). After that the expectation values of observables can be...

Hi, Homework Statement One mole of a diatomic ideal gas performs a transformation from an initial state for which the temp. and vol. are respectively 291K and 21000 cc, to a final state in which temp. and vol. are 305K and 12700cc - a straight line in the P,V diagram. Find work performed, and...

Hello all This question is probably a bit ridiculous, but here goes: Hypothetically, If any given closed system has obtained absolute zero temp, does any media (time, gravity, events)occur within? Thermodynamically, Wouldn't this be a state of infinite entropy? Can anyone describe such a...

Homework Statement A gas within a piston-cylinder assembly undergoes a thermodynamic cycle consisting of three processes: Process 1-2: Constant volume, V_1=0.028m^3, U_2-U_1=26.4kJ Process 2-3: Expansion with pV=constant, U_3=U_2 Process 3-1: Constant pressure, p_2=1.4 bar, W_{31}=-10.5kJ...

Hi all, This has been bugging me all day, so I thought I'd seek the help and advice of the internet. When a plane is stationary, you’d have to say that its jet engines are doing no useful work. The engines apply a static force on the airframe and could be said to be running at zero...

Homework Statement Can anyone help on the below? I have been working on this for days and still can't find the solutions?!? Homework Equations Steam ar 40 bar and 400C enters the high pressure turbine of a steam power plant at a rate of 20kg/s and explands to a pressure of 3 bar at...

I got this question wrong on a test: What is the equilibrium condition for an isolated system? I think the answer he wanted is the system is a maximum entropy, and that makes sense to me. But I put dS =0, which I think is basically the same thing. dS would be zero iff the system is at...

Homework Statement I was given the hard task of matematically modeling the human urinary system. I have to keep into account all the things going on. We CAN NOT model the bladder as being a sphere. So that is the main problem. It has the shape of an onion more or less. And it reduces and...

i have studied my lecture notes back to front and looked high and low for a clue how to do this question but i tried in a) constructing an expression for u and came up with DU= +TDS -PDV - FDL BAUT I COULD BE MILES OUT. could anyone help. thanks here it goes: A piece of rubber of...

Homework Statement A cylinder has a well fitted 2.0 kg metal piston whoe cross sectional area is 2.0 cm2 The cylinder contains water and steam at constant temperature. The piston is observed to fall slwoly at a rate of 0.30 cm/s because heat flows out of the cylinder through the cylinder...

Dear collegue, I would like to ask you if some body know if there are explicit or implicit relation between "mean free path" and "thermal equilibruim" Many thanks for your response. Best regards.

1. A gas is compressed from 10.00 L to 2.00 L at a constant pressure of 0.800 atm. In the process, 400 J of energy leaves the gas by heat. (a) What is the work done by the gas? (b) What is the change in its internal energy? so for part a, i have tried: P*deltaV=W 8.106E4 * 8 =...

is it possible to have a process that is both adiabatic and isothermal? i would appreciate if someone could explained that to me. if possible, could you please give me an example in real life. Thanks

Hey just two questions i need a little bit of homework help on...they just aren't clicking and maybe I am just approaching them the wrong way. A good way to start or any help would be greatly appreciated for them. Thanks :) The pressure question: A 0.13 kg balloon is filled with helium...

I always wondered why time wasn't more of an issue in thermodynamics. for example, if I have a metal at temperature 600 Kelvin. How would one go about calculating the time it took to reach thermal equailibrium if I put the same metal in an enviornment at 300 Kelvin? What would the time to...

A cylinder contains 1kg of saturated H20 at 30C. This piston has a cross-sectional area of .065m^2, a mass of 40kg, and rests on stops. With the piston in this position, the volume of the H20 is .1m^3. The external atmospheric pressure is 94Kpa and g is 9.75m/s^2. Heat is transferred to the...

in carnot cycle isothermal heating at constant pressure cannot be achieved in practice in superheated region why?but in case of raNKINE cycle it can be obtained, WHY?

well at my chemistry class i was taught that according to the 3rd law of thermodynamic, zero entropy exist at absolute zero for perfect crystal structure. But somewhere outside the class i also notice about einstein-bohr condensation that says that at zero kelvin, all particles would come...

Appreciated members of this forum: Suppose we have an infinite set of n carnot cycles and we know the efficiency of each cycle of the set: E1,E2,E3,E4,E5,,,,,En , where En is the efficiency of the nth cycle. E1= 1-Ta/Tb1 , E2= 1-Ta/Tb2, E3= 1-Ta/Tb ... En=1-Ta/ Tbn Ta is the...

Dear friends, I have asked the following question before, but I am not still satisfied with the answer given by the experts of this forum. In Einstein equation E=m/c2 ¿ Does E equal to the thermodynamic internal energy of matter plus kinetic energy plus potential energy of a system?. ¿...

Ok, I was trying to think of a first problem/question to pose to everyone for my first pose, so here it goes... (there's a lot of questions and topics already posted, so someone may have already asked this) Situation: One Antimatter Proton and One normal matter proton are on a collision...

Believe it or not, but working in a cement plant led me to an interresting question in thermodynamics. The original problem is related to lumps formation in a silo containing hot cement. It involves gypsum dehydration and the reverse reaction, hemihydrate (or plaster) hydration...

I hope someone else finds this interesting, since it through me for a loop for a while. Ok, so time dilation occures in gravitational fields. I used the solution for the time coordinate transformation between "free" space and the space under gravitational influence: t_g =...

Dealing with isothermal lines. How would you go about proving if the two lines are parallel if no values are given for the Pressure or the Volume? This is what I've got so far: Q = -W dU = 0, where U is internal energy. P1V1 = nRT P2V2 = nRT P1V1=P2V2 Or: P1/P2 = nRT1 / nRT2...

I am confused about statistical entropy and thermodynamic entropy. Are they actually the same?

I have problem understanding what does mean when we talk about kinetic and thermodynamic stability of an oxide? Which process is related to the kinetic and which to the thermodynamically stability? Thank you!

Gas in a container is at a pressure of 1.20 atm and a volume of 8.00 m3. (a) What is the work done by the gas if it expands at constant pressure to twice its initial volume? wrong check mark J (b) If it is compressed at constant pressure to one quarter of its initial volume...

if d(G/T)=(-H/T^2)dT then why can it also equal d( delta G/T)= -delta H/T^2?

A thermometer has a quartz body within which is sealed a total volume of 0.410 cm3 of mercury. The stem contains a cylindrical hole with a bore diameter of 0.10 mm. How far does the mercury column extend in the process of rising from 10°C to 86°C? Neglect any change in volume of the quartz. I...

for the following question: spectroscopic observation of molecular N2 in an electrical discharge shows that the relative numbers of molecules in excited bivrational states with energies given by (epsilon)i=(i+1/2)hv are i 0 1 2 3 ni/n 1.00 0.25...

Our question states : "A system enclosed by an impermeable, adiabatic boundary is necessarily in thermodynamic equilbrium. True or false" The textbooks only define thermodynamic equilibrium for two systems. I.e systems have to be in thermal equilbrium (same T), and there must be no...

Hi all , I have 2 questions, I don't know how to derive the equations, please help. Thank you. 1)A reversible adiabatic expansion of 2.5 moles or He from a volume 9L at 300K to a final volume of 28L. Find work(W), heat(Q), internal energy(U) and enthalpy change(H) and final temperature. (He...

Sorry about the double post, I had technical difficulties that I was working on and the title of my orginal post got screwed up. I'm having problems getting started on this one. A gas undergoes a thermodynamic cycle consisting of 3 processes process 1-2 compression with...

I'm having problems getting started on this one. A gas undergoes a thermodynamic cycle consisting of 3 processes process 1-2 compression with pressure(p)*volume(V) = constant, from p_{1} = 1 bar V_{1} = 1.6m^3 to p_{2} = ? V_{1} = .2m^3 U_{2}-U_{1}=0 process 2-3 Constant...

Ok, the first question is this: It asks me to show that the following relation holds for a reversibe adiabatic expansion of an ideal gas: T/P ^(1 - (1/Gamma)) = constant Where Gamma = the ratio of: C_p/C_v the specific heats with constant pressure and volume, respectively. I...

I have in front of me an equation for energy in a system [ U=U(P,V) ]. I'm being asked to find "the equation of the adiabats in the P-V plane". What are they looking for? I know an adiabat is a system with no heat transfer, meaning that the energy of the system would equal the work done on...

I was wondering if anyone knows where i can find the work relations for an ideal gas including isometric, isothermal, polytropic, isobaric, etc.

An ideal gas is carried through a thermodynamic cycle consisting of 2 isobaric and 2 isothermal processes. Show that the nett work done is W=P1( V2-V1)ln ( P2/P1) i am really stuck at this qn for very long. Please help me

I've read that there is a thermodynamic arrow of time, based on the fact that entropy can only increase or stay at the same level. But why is it thought to be directed in the same direction as the psychological arrow of time. Could there be an arrow of time directed in the opposite direction to...

I can't remember for the life of me how to read Themodynamic property tables! I want to find answers to questions for example: What is the internal energy of 1kg of saturated steam at 10 bar or 3kg of water at 130C Can anyone help or know of any good websites which has information on how...

As temperature is emergent and is only describing the speed of molecules in a substance, is it meaningful to speak of temperature in an empty space? If not, can we say that the microwave background radiation is "heating" up the universe? As most of the universe is empty space

any isolated macroscopic system, like a large group of atoms, always tends to reach a state that has the maxium entropy. if the electrons in this group of atoms are excited, they will give out their energy so that more degrees of freedom are activated, hence the entropy of the whole system...

Q. A 2-m3 rigid tank contains nitrogen gas at 500kPa and 300 K. Now heat is transferred to the nitrogen in the tank and the pressure of nitrogen rises to 800 kPa. The work done during this process is ... Do we need to use W = P2v2 - P1v1/ ( 1-n) Some guidance requested please. Thanks,

an unusual but not too technical, thermodynamic question for you guy/gals hi, I've got an unusual q. that i don't think computer forums members can handle too well. they know their watercooling very well and that's what my q. relates to. but more...