Thermodynamic Definition and 502 Threads

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 Using information from tables, calculate the equilibrium constant K of the following reaction at 32 degrees C. PCl_5 \rightarrow PCl_3 + Cl_2 \Delta H^0_{rxn} = 68.6kJ a) 4.62 \times 10^{-3}atm b) 216 atm c) 7.81 \times 10^{-11}atm d) 163 atm Homework Equations \Delta...

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.

Hi Guys! please help me in deriving this: A container of volume V_{c} contains gas at a high temperature. The container id connected through a stopcock and a capillary tube to a cylinder equipped with a frictionless piston. When the stopcock is opened, the gas enters the cylinder while at...

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...

Sorry for some many questions here. I'm stuck on all of these problems and it's starting to really frustrate me. I'm not sure what more to do. 1. A sample of Helium behaves as an ideal gas as energy is added by heat at constant pressure from 273 K to 403 K. If the gas does 20.0 J of work...

I got into a discussion about the "arrow of time" recently, and one point I brought up is that for a system governed by time-symmetric laws, if you place no special restrictions on the initial conditions but instead pick an initial state randomly from the system's entire phase space, you will be...

Let’s say we have a 1 mol system in a state A (Pa,Va,Ta are given) and we take it to a state B(Pb,Vb are given) . We want to know what’s the maximum work we can give to a reversible work source. Considering the process is carried out attached to a 150 K heat source, the only data available is...

Dear friends, I’m having trouble with this thermodynamic problem. I apologise if you don’t understand my poor English (I’m writing to you from Spain!) We’ve got two cylinders (1 is adiabatically isolated from 2 but not from the outside, where Pressure P and Tº are constant) and cylinder 1...

Dear friends, I’m having trouble with this thermodynamic problem. I apologise if you don’t understand my poor English (I’m writing to you from Spain!) We’ve got two cylinders (1 is adiabatically isolated from 2 but not from the outside, where Pressure P and Tº are constant) and cylinder 1...

Thermodynamics textbooks indicates that the total energy of a system E is given by the following equation E = U + Ek +Ep where U is the internal energy due to atomic or molecular interactions, Ek is the kinetic energy due to the velocity of the system ,and Ep is the potential...

Determine the thermodynamic equilibrium constant of the following reaction to explain why graphite is not an easily converted, inexpensive source of diamond at 90 F… C(graphite) = C(diamond). Given this evidence, need diamond owners worry about disintegration of their diamond jewelry to...