Thermodynamic Definition and 459 Threads

In thermodynamic perturbation theory (chapter 32 in Landau's Statistical Physics) for the Gibbs (= canonical) distribution, we have E = E_0 + V, where V is the perturbation of our energy. When we want to calculate the free energy, we have: e^{-F/T} = \int e^{-(E+V)/T} \mathrm{d}\Gamma We can...

I have read that every body possesses some energy of vibration due to the thermodynamic character and it is equal to 1/2 kT. Does this mean that we can detect the vibrations of bodies? Or ,as it is, does it ultimately end up as heat? Regards, Boltzmann2012

If we add a small amount of heat δq to a liquid at its boiling point Tb, it could either increase its temperature a small amount dT = δq/Cv, or suffer a phase change into vapor. Experimentally, we see that liquids remain at Tb until the phase change is complete, and only then continue...

I don't have the intuitive picture of thermodynamic 2nd law, in terms of statistical mechanics. That is, why should the number of microstates be maximized in equilibrium? Anyone gives an intuitive explanation? Thanks a lot.

Homework Statement Plot cp as a function of temperature for O2? How does this compare with the cp expected for a diatomic ideal gas. Add this constant value to your plot. At what temperatures does the real value of cp approach that expected for a diatomic ideal gas. Homework Equations...

hi, I'm simulating a system of molecules (water) and in order to pass through a barrier they have to overcome an energy barrier of 4kT. What is the probability of a water molecule passing the barrier or perhaps what is the average energy of a water molecule in my system? I know it's 1/2 *kT...

Homework Statement http://i.imgur.com/2WKCR.jpg Homework Equations Potentially: L(final) = L[1 + tau/(YA) + alpha(T - To)] The Attempt at a Solution Frankly I have no idea where to begin.

dU = TdS - P dV Is in my book derived by viewing a proces of changing volume and energy in two separate steps. First you add energy with volume fixed, then change the volume. I'm just not sure that I understand why, you are allowed to do this. I know the changes are infinitesimal but why is...

Homework Statement Carpet steamer marketed for Greenland. Add up to 2 kg of snow or ice (no colder than -10°C) that will be converted to steam within 5 minutes. How powerful would the steamer need to be to make this claim? Know that 2108 J/kg K; Hf= 3.24*10^5 J/kg; Cwater= 4184 J/kg K; Hv =...

Homework Statement a) what is the density of dry air when the surface pressure is 1010hPa and the temperature is 27°C. b) what is the internal energy of 1kg of dry air under these conditions? Homework Equations P=p*R*T where P is pressure and p is density. The Attempt at a...

What the relationship between catalyst and thermodynamic. In activation energy as we know, it reduces the activation energy and what about thermodynamic way?

In thermodynamical equilibrium what would be the proportion of hydrogen to helium-4? According to the proton-proton chain branch I it would seem that the equilibrium would be 75% H-25% He-4? is this correct? (This is of course an unrealistic scenario).

Homework Statement [/B]A bullet traveling at 100 m/s strikes the wall inelastically. It is observed that the bullet's temperature rises by 10 Kelvin due to the collision. Find the specific heat capacity of the bullet if all of the bullet's energy goes into heat. Homework Equations ΔQ=mcΔT...

Homework Statement The mixing tank shown here initially contains 50 kg of water at 25°C. Suddenly the two valves and the single outlet valve are opened so that two water streams, each with a flow rate of 5 kg/min, flow into the tank, and a single exit stream with a flow rate of 10 kg/min...

Homework Statement See attachment ecxample001. Homework Equations See attachment D11. The Attempt at a Solution In the first equation (Cp/R = a+bT+cT^2...etc.), Cp/R is the constant pressure specific heat. The general formula for enthalpy change is h2-h1 = integral[Cp]dT, so does...

A heat Engine receives 6 kg/h gasoline which has a calorific value of 42000 kj/kg. If heat rejected from the engine is 40 kw, calculate a- the power done by the engine b- the engine effiecincy -this wt i got today in my exam and unfortuntely i didnt study it well but i did the following ...

For a thermodynamic process, what equations would be used to find the change in Gibbs and Helmholtz free energy when: a.)The process is adiabatic b.)The process is isothermic c.)The process is at constant volume d.)The process is at constant pressure I know ΔG=ΔH-TΔS and ΔA=ΔU-TΔS but do...

Homework Statement cp=cv+TV?^2/? Homework Equations cp=T/N(\partialS/\partialT)p The Attempt at a Solution I have the equation, just not sure how to apply it? Any help would be appreciated

Homework Statement The figure shows a thermodynamic process followed by 130 mg of helium. How much work is done on the gas during each of the three segments? p_1 = 1.08 atm, p_2 = 5.41 atm, p_3=1.08 atm T_1=133 C, T_2=T_3=1760 C V_1=V_2=1000 cm^3, V_3=5000 cm^3 These are answers...

Hi everyone, I'm learning equilibrium thermodynamics on my own. I'm wondering how is the Kp(equilibrium constants) in the JANAF tables defined? Which reaction formula does it refer to? Thanks in advance.

Homework Statement A mole of ideal gas with a temperature T1=300K is expanded isobarically until its volume is tripled .Then the gas gets colder isochorically until we reach the temperature we had in the beginning 300 K.Find the work of the gas. Hint : We have a thermodynamic cycle . Homework...

Homework Statement I have a problem which I will attach a picture of, regarding a system composing of a heat recovery steam generator and a turbine. I have to work out the power output of the turbine, which I think I will be fine with. What I would like to know is, how does the combustion...

Homework Statement The question is as following: One litre of an ideal gas, initially at atmospheric pressure, is held at a constant temperature of 300 K (by maintaining good thermal contact with a thermal reservoir held at this temperature). The volume is decreased until the pressure doubles...

Hiya guys, I've just started a project, of which the aim is to develop a thermodynamic property database for hydrcarbon fuels. I've been asked to start by reading up on the maxwell relationships and clapeyron equation etc. so hopefully this will give you an idea of what I am trying to...

Homework Statement The problem is as following: Homework Equations \Delta E = \Delta Q-\Delta W The Attempt at a Solution Now I know that if work is done by the system then work sign is negative and that if volume remains unchanged then no work is done. Am I right to say that Internal...

I'm struggling to derive some thermodynamic equations from this http://my.safaribooksonline.com/book/chemical-engineering/9780132441902/thermodynamic-properties-from-volumetric-data/ch03lev1sec1" : Homework Statement I'm trying to derive all the equations from 3.8 to 3.14 for Pressure...

I have the answer to this question but I'm finding it hard making sense of it... Q5) Dervive a relationship relating Cp-Cv to the isothermal compressibility (∂p/∂V)T and the coefficient of thermal expansion (∂V/∂T)p. Hint: consider the intensive entropy S as a function of T and V. So I've...

In an isobaric expansion process, the pressure of the gas is kept constant. Because of the increase in volume the constant pressure can only be archived by increasing temperature. Then I want to ask is the pressure of the gas necessarily equal to the external pressure throughout the whole...

1. Statement of the Problem One mole of a monatomic ideal gas is taken through the reversible cycle shown. Process bc is an adiabatic expansion, with P_b = 10.0 atm and V_b = 1.00E-3 m^3. Find a) the energy added to the gas as heat, b) the energy leaving the gas as heat, c) the net work done by...

Homework Statement Show that the work done by a reversible function from P1V1 to P2V2 is W = (P1V1 -P2V2)/ (x - 1) using the relation PVx = C where X and C are constants Homework Equations dW = PdV The Attempt at a Solution I'm going to have to update this more when i get...

Hi, before I start this is not coursework or any work attached to my degree but part of an internship at a neutron research facility at a level appropriate for Masters students and higer, so I felt it necessary to post it here rather than the homework section (sorry if I'm mistaken). I've been...

After a bit of calculation, I came up with the following quantity for the bit-entropy of a thermodynamic system. We have the following assumptions: 1. System at thermal equilibrium. 2. Ideal gas. 3. Monatomic gas (i.e. no internal degrees of freedom for particles). 4. All particles have equal...

Homework Statement I'm probably over thinking this question. An ideal gas is placed in a thin walled aluminum cylinder and slowly compressed to 25% of its original volume. The process is best described as adiabatic, isothermal, isochoric, or isobaric? Homework Equations none The...

I read that entropy is a measure of disorder. Or in other words, unpredictability. So if I have a fair 50/50 coin. It is at maximum entropy (unpredictability). If I have a two headed coin I have zero entropy. It seems that the more possible unpredictable states, the higher the entropy. Now...

A steam power plant operates on an ideal reheat–regenerative Rankine cycle with one reheater and two open feedwater heaters. Steam enters the high-pressure turbine at 10 MPa and 600°C and leaves the low-pressure turbine at 7.5 kPa. Steam is extracted from the turbine at 1.8 and 0.3 MPa, and it...

This is a very simple problem, though I have arrived at two different results and I would like some help to procceed (I'm not sure if this is the right section, though this is not a homework): "2kg are confined in an adiabatic cilinder through a frictionless piston activated by an elastic...

Homework Statement http://i754.photobucket.com/albums/xx183/reddiesel08/Q2.jpg Homework Equations e = 1 - (Tc/Th) (Temp in Kelvins) The Attempt at a Solution e = 1 - (300k/520k) = .42 or 42% No because the engine can only perform 42 J of work for each 100 J of energy. Homework...

Urgent! Thermodynamic refrigerator Homework Statement One mole of a monatomic ideal gas is allowed to expand isothermally from an initial volume of 10 liters to a final volume of 15 liters, the temperature being maintained at 400K. The work delivered is used to drive a thermodynamic...

Hi Everyone, I have been researching for days, and am still very confused, so thought I might turn here for assistance. I know the minimum free energy represents the state of maximum stability for a system. Free energy is decreased when enthalpy decreases and entropy increases. I understand...

Homework Statement A thermodynamic engine is operated between two cooler bodies A and B, extracting work until the two cooler bodies reach a common temperature T_f. This work is then used as the input to a heat pump, extracting heat from the cooler pair and heating the hot body C. Find the...

Hey everyone, I'm a bit confused with the meanings of f, g, and fg subscripts in the thermo steam tables (e.g. hf, hfg, hg). If there is saturated steam, part of the enthalpy is in liquid, hf, part is encapsulated in the vapour, hg, but what is hfg? Also h = hf + (x)hfg. h here is the total...

It is often said that phase transitions only exist in the thermodynamic limit based on some proof like: -A system has time-reversal symmetry thus its TOTAL free energy F(H)=F(-H) (H is the field) therefore the magnetization is M(H)=\frac{\partial F(H)}{\partial H}=\frac{\partial...

Homework Statement 1. Explain the term thermodynamic potential. 2. Explain the motivations for defining the enthalpy, the Helmholtz free energy and the Gibbs free energy. 3. The Helmholtz and the Gibbs free energy are measures of the distance to thermodynamic equilibrium. Explain...

Homework Statement A 80 kg man is running and each second he needs a energy of 812.77 J. Find: a) The speed (in m/S) of the runner. b) How many kcal will be burn in one hour with the speed calculated in a)? Homework Equations Kinetic energy; kcal = 4184 J The Attempt at a...

Homework Statement I was given and writing assignment which requires me to write a two-page report on how an organic matter like a potato can exist according to the Laws of Thermodynamics. I will be evaluated on how well I explain scientific principles and how accurate my statements are. The...

Well I've been doing fairly complex thermodynamics in classical mechanics lectures with a bit of medium to advanced class, first of all , it took me a very long time to wrap my head around the concept of Entropy, however I still don't understand why we use ln (Natural Log) to calculate the...

Homework Statement A 70 ft3 rigid insulated tank contains air at 14.7 psia and 80 º F. The tank is connected to a supply line through a valve. Air is flowing in the supply line at 75 psia and 80 º F. The valve is opened, and air is allowed to enter the tank until the pressure in the tank...

Question : State which type of thermodynamic system (Isolated, Closed, Open) the following are... Include in your answer which type of system they are relative to short and long time periods. A list then followed. I'm unsure about only one. A thermal flask. I know in the long term a...

Hey all, I'm looking for a version of steam/water thermodynamic properties for excel. I need it to be able to compute properties based on pressure and entropy. Something similar to the X Steam Tables (http://www.x-eng.com/XSteam_Excel.htm) would be awesome, but again, I need the ability to...

As a practical matter, the internal energy of a system is treated as a state function of a the system and is concerned only with the kinetic energy of particles, not the potential energy. So for thermodynamic entropy, S=E/T, (S=entropy, T= absolute temperature) I'm considering E to be kinetic...