What is Thermodaynamics: Definition and 151 Discussions

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Copyright strictly reserved to Prof Prof. M.S. Ananth and NPTEL, Govt of India. Duplication prohibited. Lectures: http://www.nptel.ac.in/courses/103106070/ Syllabus: http://www.nptel.ac.in/syllabus/syllabus.php?subjectId=103106070

Copyright strictly reserved to Prof Prof. M.S. Ananth and NPTEL, Govt of India. Duplication prohibited. Lectures: http://www.nptel.ac.in/courses/103106070/ Syllabus: http://www.nptel.ac.in/syllabus/syllabus.php?subjectId=103106070

Copyright strictly reserved to Prof Prof. M.S. Ananth and NPTEL, Govt of India. Duplication prohibited. Lectures: http://www.nptel.ac.in/courses/103106070/ Syllabus: http://www.nptel.ac.in/syllabus/syllabus.php?subjectId=103106070

Copyright strictly reserved to Prof Prof. M.S. Ananth and NPTEL, Govt of India. Duplication prohibited. Lectures: http://www.nptel.ac.in/courses/103106070/ Syllabus: http://www.nptel.ac.in/syllabus/syllabus.php?subjectId=103106070

Copyright strictly reserved to Prof Prof. M.S. Ananth and NPTEL, Govt of India. Duplication prohibited. Lectures: http://www.nptel.ac.in/courses/103106070/ Syllabus: http://www.nptel.ac.in/syllabus/syllabus.php?subjectId=103106070

Copyright strictly reserved to Prof Prof. M.S. Ananth and NPTEL, Govt of India. Duplication prohibited. Lectures: http://www.nptel.ac.in/courses/103106070/ Syllabus: http://www.nptel.ac.in/syllabus/syllabus.php?subjectId=103106070

Copyright strictly reserved to Prof Prof. M.S. Ananth and NPTEL, Govt of India. Duplication prohibited. Lectures: http://www.nptel.ac.in/courses/103106070/ Syllabus: http://www.nptel.ac.in/syllabus/syllabus.php?subjectId=103106070

Copyright strictly reserved to Prof Prof. M.S. Ananth and NPTEL, Govt of India. Duplication prohibited. Lectures: http://www.nptel.ac.in/courses/103106070/ Syllabus: http://www.nptel.ac.in/syllabus/syllabus.php?subjectId=103106070

Copyright strictly reserved to Prof Prof. M.S. Ananth and NPTEL, Govt of India. Duplication prohibited. Lectures: http://www.nptel.ac.in/courses/103106070/ Syllabus: http://www.nptel.ac.in/syllabus/syllabus.php?subjectId=103106070

Copyright strictly reserved to Prof Prof. M.S. Ananth and NPTEL, Govt of India. Duplication prohibited. Lectures: http://www.nptel.ac.in/courses/103106070/ Syllabus: http://www.nptel.ac.in/syllabus/syllabus.php?subjectId=103106070

Copyright strictly reserved to Prof Prof. M.S. Ananth and NPTEL, Govt of India. Duplication prohibited. Lectures: http://www.nptel.ac.in/courses/103106070/ Syllabus: http://www.nptel.ac.in/syllabus/syllabus.php?subjectId=103106070

Copyright strictly reserved to Prof Prof. M.S. Ananth and NPTEL, Govt of India. Duplication prohibited. Lectures: http://www.nptel.ac.in/courses/103106070/ Syllabus: http://www.nptel.ac.in/syllabus/syllabus.php?subjectId=103106070

Copyright strictly reserved to Prof Prof. M.S. Ananth and NPTEL, Govt of India. Duplication prohibited. Lectures: http://www.nptel.ac.in/courses/103106070/ Syllabus: http://www.nptel.ac.in/syllabus/syllabus.php?subjectId=103106070

Homework Statement Some gas at 300K is enclosed in a container. Now the container is placed on a fast moving train.is the change in temperature of the gas the same as the change dT observed when train suddenly stops? Homework Equations 1/2mv^2=dU?? or dU=0?? The Attempt at a Solution...

From wikipedia, The general equation is $$\frac{df}{dt} = (\frac{∂f}{∂t})_{force}+(\frac{∂f}{∂t})_{diff}+(\frac{∂f}{∂t})_{coll}$$ where the "force" term external force, the "diff" term represents the diffusion of particles, and "coll" is the collision term. So shouldn't be df/dt=0 when it is...

Homework Statement A rod of length ##L_o## is kept on a friction-less surface. The coefficient of linear expansion for the material of the rod is ##\alpha##. The the temperature of the rod is increased by ##\Delta T## the strain developed in the rod will be? Homework Equations $$ \Delta L=...

Hi there. Earlier today I decided to pull out ice cream from the freezer. It is a magnum-type ice-cream and comes in a plastic wrapper. Once I opened the wrapper and removed the ice cream, I left the wrapper on the kitchen table and noticed something rather bizzarre (to me at least)...

Homework Statement Let 3/2kT be the kinetic energy of ideal gas per molecules. T the absolute temperature and N the avogadro number. Answer the following questions : 1) when the volume doubled at constant temperature. How many times the kinetic energy per molecule become greater than before...

Homework Statement The initial state of 0.1 mol of an ideal monatomic gas is P0=32 Pa and v0=8m3. The final state is P1=1 Pa and V1=64m3. Suppose that the gas undergoes a process along a straight line joining these two states with an equation P=aV+b, where a =31/56 and b=255/7. Plot this...

Homework Statement I don't understand the derivation of the right side of the last equation. Homework EquationsThe Attempt at a Solution I got to this point, I also don't understand why it did not include C_2 for the variation of temp. along the fin. I am guessing the right side is the...

Homework Statement Homework EquationsThe Attempt at a Solution I thought it would become d/dx(-kAc*dT/dx)+hp(T-T)=0 instead of where the equation in the red box? I don't see how are they equivalent [/B]

Homework Statement In a waterfall about 20 billion liters of water per hour drop about 110 m. What is the increase of the water temperature, assuming that the entire gain of heat is transferred to the water? Homework Equations I'm more curious about the question in itself. Perhaps I'm missing...

I was reading the derivation of Boltzmann distribution using the reservoir model. lets call the reservoir by index R and the tiny system by index A. In the derivation they proposed that the probability for being at energy e (for A) is proportional to the number of states in reservoir. I didn't...

So, I have noticed that when people are crowded in small rooms, it feels hot. In fact, everyone in the crowd feels hot and starts sweating. I am wondering about the origin of all this heat. I do know that by first law of thermodynamics, if two people touch each other and if one of them feels...

Homework Statement A non-conducting piston of mass m and area of cross section A is placed on a non-conducting cylinder. Intial height of piston is h and spring is relaxed with a spring constant k.Then,work done in displacing pistin by heating gas is (x is the displacement of the pistion)...

I've written a short text adapted from a previous post by Count Iblis. I'll append it below. It shows that irreversible PV-work is always smaller than reversible, which fits very nicely with W = Pext ΔV. I'd be interested if there's a way to show that W is exactly equal to Pext ΔV for all...

"A Carnot engine operates using a heat source at 500 °C, and a heat sink at room temperature (20 °C). Suppose that as a heat source, you use the combustion of 100 cubic feet of natural gas at room temperature and pressure (e.g. in a fuel cell of some kind). Under ideal conditions, what is the...

Homework Statement a) A mass of 0.12 kg of air has an initial temperature of 500°C and pressure 0.8 MPa. If the air is expanded according to the law pV1.2 = c to a final volume of 90 litres, determine i) its initial volume, ii) its final pressure, iii) its final temperature...

My question is regarding a few descriptions of Entropy. I'm actually unsure if my understanding of each version of entropy is correct, so I'm looking for a two birds in one stone answer of fixing my misunderstanding of each and then hopefully linking them together. 1) A measure of the tendency...

Hello everybody. I am trying to understand better what happens at a liquid-gas phase transition for the Van Der Waals model. From what I have understood, from the Van Der Waals model we are able to plot the curve P(V) and to calculate the free energy F. Here are such curves : Then, we...

I have been trying to understand the role of a cavity as a black body radiator in the derivation of planks black body radiation law but it has left me with 5 main questions: 1. If an object is a perfect absorber it must also be a perfect emitter, meaning that (allowing for a cavity not being a...

Why is it written that enthalpy (##H##) is constant for Joule-Thompson expansion? It seems the essence of this process is to convert from one pressure to another with no heat loss. How does that connect with enthalpy being constant? When I learned about enthalpy it seemed to be most relevant to...

Homework Statement I am confused on when will pressure of two states be the same for a piston cylinder device. Below are two problems where one's final pressure equals the initial pressure and one is not. Homework EquationsThe Attempt at a Solution Initially, I thought a piston-cylinder...

Homework Statement The saturation temperature is given in the parentheses. then what is Sat. on the Temperature column? Homework EquationsThe Attempt at a Solution

[Mentor note: Thread title changed to describe actual problem being presented] 1. Homework Statement Homework Equations The Attempt at a Solution I understand you have to interpolate temperature and pressure of the saturated vapor from the table, since there is no matched final specific...

Homework Statement Homework EquationsThe Attempt at a Solution ## dS = \frac { dQ_{rev} } { T } ## Assuming that isothermal process is a reversible processes, ## dU = dQ – pdV## For isothermal process, dU = 0. ## dQ = pdV ## ## pV = nRT##, where n is number of moles. For one mole, ##...

Homework Statement Homework EquationsThe Attempt at a SolutionChemical potential is defined as ## \mu = Gibbs potential per particle ##. So, is the system consists of N particles, ##\mu = \frac { G } {N } ##. Now, dG = VdP – SdT ## \frac {dG } { N } = \frac { VdP } { N } - \frac { SdT }...

Homework Statement Homework Equations The Attempt at a Solution I don't understand how the solution got its values, not from the tables right? because I couldn't find such value from all of the tables. Since the pressure is less than the saturated pressure at given temperature, it is in...

Homework Statement The temperature of n = 19 mol of argon gas is increased from T1 = 21 oC by Q = 4.4 kJ heat transfer, while the gas pressure is kept constant. What is the new gas temperature in Celsius degrees? Homework Equations and as its a monoatomic gas I think this means that the...

Homework Statement The surface tension of a layer of water obeys ## \sigma = a- bT##, where ##T## is the temperature. Find the change in temperaure, ##\Delta T## when the area is increased isentropically. Homework Equations ## dU = dQ -dW## , ##dW = \sigma dA##, ##dU = C_A dT + [\sigma...

Homework Statement The coefficient of thermal expansion and isothermal compressibility of a gas are given by ##\alpha_P =\frac{V-b}{TV}## and ##\kappa_T = \frac{V-b}{PV}## find: a) The equation of state b) If the heat capacity at constant volume ##C_V## is constant, what is ##\delta U##? c)...

I have also asked this question in SO and CFD online Assuming that we have a pneumatic cylinder-piston with arbitrary but known surface area A, a known clarence c, and a known length L. What is the best model to describe the total steady state force applied on the piston considering the...

Homework Statement The temperature of a 12-oz (0.354-L) can of soft drink is reduced from 20 to 5 ºC by a refrigeration cycle. The cycle receives energy by heat transfer from the soft drink and discharges energy by heat transfer at 20 ºC to the surroundings. There are no other heat transfers...

A turbine operates under steady-flow conditions. It receives steam at a pressure of 15 bar, specific volume of 0.1318 m³/kg, velocity of 30 m/s and specific internal energy of 2594.5 kJ/kg. The steam leaves the turbine at a pressure of 30 kPa, velocity of 90 m/s, specific volume of 4.25 m³/kg...

Homework Statement Estimate the pressure increase required to impart 1 J of mechanical work in reversibly compressing 1 mol of silver at room temperature. What pressure rise would be required to impart 1 J of work to 1 mol of alumina at room temperature? For alumina take the molar volume to be...

Homework Statement Homework Equations The Attempt at a Solution Is it an assumption because the difference in height is small?

Homework Statement Can you please show how to solve this question (I am not asking it for homework. I am asking because it would help me understand better). Determine the entropy change in sys, surr, uni, when a sample of helium has of mass M grams at 298K and 1 bar doubles its volume in...

Homework Statement Homework Equations P=F*V, dU=Q-W?, W=m(h1-h2) The Attempt at a Solution I have the initial conditions and final conditions written out. For W=m(h1-h2), I have W=9.48(h1-h2). I am having problems with the h values, which can be found in the steam tables.

Homework Statement [/B] Im trying to find the efficiency of a gasoline engine regarded as a control volume. Am I right to use the HV as total energy input into the system? Assuming the enthalpy of formation of the fuel can't be found. I am really wondering if enthalpy of formation equals the...