Thermodynamics Definition and 1000 Threads

andrewkirk submitted a new PF Insights post Partial Differentiation Without Tears Continue reading the Original PF Insights Post.

Hello everybody, I have two questions: 1) Is it possible to define a temperature for single particle (or atom or molecule)? If so, how? 2) How to model with quantum Hamiltonian an exchange of energy between a single atom (or molecule) and a reservoir at given temperature ##T## ? Thank you...

Hi everyone! I am confusing myself with this topic and I would appreciate some insight into this. You see, one takes the area of a PV graph to obtain the work done on the system (for compression) or by the system (for expansion). However, I am learning that in the irreversible path, compression...

The reaction CO2 + 4 H2 <==> CH4 + 2 H2O (liq) at 25oC is downhill with a gibbs energy of -31 kcal/mol. It has a negative entropy of -98 cal/K. Thus an isolated system of the two starting gases should go to equilibrium on the basis of the Gibbs energy value, but the process would then...

Homework Statement When a gas is enclosed in an impermeable box and heated to a high temperature T, some of the neutral atoms lose an electron and become ions. If the number density of neutral atoms, ions and electrons is Na , N i and N e , respectively, these can be related to the average...

I learned about entropy is chemistry, can someone please explain how this term is used in physics? Thanks.

An ideal gas at initial state has temperature 300 K has been compressed under constant pressure of 30 Pa from volume 3 cubic meters to 1.8 cubic meters. In the process 75 J of heat was lost. A. Find the change in internal energy B. Find the final temperature I tried two methods in A and they...

Homework Statement Derive the equation ##U=-T(\frac{\partial A}{\partial T})_V## where ##U## is the internal energy, ##T## is the temperature, ##A## is the Helmholtz function. Reference: Heat and Thermodynamics, Zemansky, Dittman, Page 272, Problem 10.4 (a) Homework Equations ##dA=-PdV-SdT##...

I was wondering how a boundary layer would be dissipative of momentum if it was under the influence of a positive heat gradient. I understand that the reason that we don't see the boundary pressure equal the stagnation pressure is that the boundary is dissipative (so excess pressure above...

Thermodynamics (Yunus Cengel Michael Boles , 8) I'm taking Thermodynamics right now at my community college and if you saw my last post about my physics teacher, you know I have the right to be paranoid about not learning enough in my classes. I've always heard Thermo for mechanical engineers...

Hi there, After spending a lot of time reading topics on the forum, and knowing that I have a TIPE( Project in French Prep School Prior to entering engineering big schools) to do for the year (I am in 2nd year of scientific preparatory school ( So i am 19 )) I decided to launch a project to...

Hi, I have a thought experiment which seems inconsistent with the 2nd Law of Thermodynamics, so there is probably a flaw in the idea somewhere. Imagine a single molecule of a heavy gas (such as SF6) in a pipe 2.5 metres high and 100mm diametre. The pipe is upright and under the normal...

My name is Liviu Marinica, I was born in Romania, and I am an 48 yo electrical engineer. My background in engineering is related to office work (design) but also field service work for electrical power equipments such as medium and low voltage switchboards, protection relays (called IED, or RTU...

Homework Statement An ideal gas with adiabatic index γ is taken around a complete thermodynamic cycle consisting of three steps. Starting at point A, the pressure is increased at constant volume V1 from P1 to P2 at point B. From point B to point C, the gas is allowed to expand adiabatically...

Hi, I am currently studying Thermodynamics and stumbled upon this equation and is slightly confused as to how this works. Hopefully someone can help me with the understanding. According to this text here, if I am not wrong e can be h + ke + pe or u + ke + pe depending on where i am looking...

Here's a thought from other thread A reply So what's the relation between gravity and the laws of thermodynamic, or should it be conservation of energy?

Homework Statement A spherical shell has inner and outer radii r_a and r_b, respectively, and the temperatures at the inner and outer surfaces are T_a and T_b. The thermal conductivity of he shell material is k. Derive an equation for the total heat current thought the shell in the steady...

Homework Statement A silicon electric circuit is 23 mg, when electricity flows through the circuit rising the energy by 7.4 mW but this circuit wasn't design for heat ventilation. Find the rate of how much the temperature is rising per second ( ΔT/Δt ) The specific heat of silicon is 705...

HOMEWORK POSTED IN WRONG FORUM, SO NO TEMPLATE I have encountered a problem at the university in which there is a thermally isolated container of constant volume in which the number of particles and temperature change with time(the temperature increases). The change in particle number ensures...

There's one equation that I've seen being used already, which by itself is quite simple, but I can't understand where it comes from. The context is as follows: suppose we have one heat engine operating between systems A and B whose temperatures are T_A>T_B. Let's suppose further that the...

1. Can I say Carnot efficiency of a heat engine is always smaller than 100 because the temperature of cold reservoir is always greater than 0 Kelvin? 2. Is the following analogy correct to describe the relation between temperature and heat energy? "Heat energy affects internal energy which...

How do you find a value for Z using the compressibility chart when the temperature line you're trying to use ends? For example, if you look at the compressibility chart and try to find a value for z with P_r = .75 and T_r = .96, you will notice that the line for T_r = .95 ends well before the...

A rigid tank with a volume of 2.00m3 contains 5.77 kg of saturated liquid-vapor mixture of water at 75 deg C. Now the water is slowly heated. Determine the temperature at which the liquid in the tank is completely vaporized. Why isn't the temperature just 75C? If it is already a mixture in...

In what follows I refer to the ideas of "Thermodynamic: Foundations and Applications" by Gyftoploulos and Beretta. The abbreviated form of my question is: In a reversible weight process, Ω1R-Ω2R = E1 - E2 (see eqn. 6.18, p. 99) is transferred out of the composite of a system A and a reservoir R...

For example, in this question.. A 11 L rigid container contains 10-kg of R134a at 100kPa. Determine the temperature and total enthalpy in the container. Why can we just assume that the temperature we're looking for is T_sat, how do we know this isn't a compressed liquid? How do we know it...

Homework Statement An ideal monatomic gas has initial pressure Po and occupies initial volume Vo. The gas undergoes an adiabatic expansion in which the volume is doubled. Calculate in terms of Po and Vo a) the final pressure of the gas b) the change in its enthalpy during the...

I'm reading Thermodynamics: Foundations and Applications by Gyftoploulos and Beretta, because the authors claim to give a presentation of classical thermodynamics without "... the lack of logical consistency and completeness in the many presentations of the foundations of thermodynamics" [from...

So I need to give an exciting thermodynamics demo based on one of the first two laws. I have found it difficult to either make it exciting enough or to make it apply to thermodynamics enough. I have a few that I have come up with but I don't think any really apply as well as I want. 1)Can...

Homework Statement Air flows steadily into a well isnulated piping junction through the two pipes and is heated by an electric resistor at uknown rate befoe exiting through the pipe. Pressure renaubs approcimetaly constant p=0.1 MPa, first inlet: volumetric flow rate = 10m^3/s, t1= 20 C, 2nd...

Hi, rank newbie here, with my first post. This one is something I figure every first year student comes up with at some point, but I don't know enough keywords to Search for an answer. (I'm not a student except in the category "of life": this isn't assigned homework) I figger, using a bit of...

For a business project, I'm looking into the viability of a greenhouse situated in Canada's far northern town of Iqaluit. The problem is how to mathematically simulate the internal air temperature of the greenhouse. What I already have are detailed 3D renderings of the greenhouse as well as all...

I was reading an answer on Quora written by Richard Muller ,a retired professor from Berkeley https://www.quora.com/Does-Richard-Mullers-new-time-theory-account-for-the-second-law-of-thermodynamics-or-any-of-times-arrows/answer/Richard-Muller-3?srid=E7fv What are your views ? I am from...

Hi I had a question about this video. Indeed if I understand the video correctly it states that energy is linked to information. But how does that work indeed knowing that energy is constant, that more entropy = less information and that entropy increases. It seems that the universe will end...

When dealing with heat transfer, there are cases where Q can be expressed by C*ΔT, for some proportionality constant C. However, in isothermal processes for example, this formula would lead to a mistake, for any value of C (because it would imply Q=0, which is not true generally speaking). What...

A very neat video showing a phase transition in rotating balls in a cup. Serves as a good analogy to other phase transions.

Hello - I just starting out in chemical engineering. I hold a batchelor's degree in Chemistry, and am making a transition to ChemE. This isn't for any class, just in general for reference, does anyone know of a good book that is primarily just thermodynamic charts, like T-S diagrams? I have...

Homework Statement A block of radioactive material is ti be used as a power source for a deep space probe which may be treated ideally as a single Carnot engine. Radioactive decay generates heat in the block at a rate Pin = dQin/dt and heat is extracted from the block to operate the probe at a...

Homework Statement Using equipartition law, find specific heat of gas containing triatomic linear molecules. Will the result be different if the molecule was non- linear? In what way? Homework Equations According to equipartion theorem, each degree of freedom gets (1/2)kT kinetic energy and...

1. Steam is the working in an ideal rankine cycle with super heating . Super heated vapor (state 1) enters the turbine at a temperature of 440 °C. Saturated vapor(state 2) exits the turbine at a pressure of 3.0 bar.2. a) Sketch T-S diagram. b)Determine the thermal efficiency of the ideal...

All of my information comes from my current chemistry class, I just want to know where I either may have misread, misinterpreted, or was mistold information. With the 2nd Law of Thermodynamics we can say $$[1]\space\space \Delta{S}_{universe} = \Delta{S}_{surroundings} + \Delta{S}_{system} >...

I know thermodynamics are the macroscopic coarse graining of microscopic degrees of freedom (like temperature and Brownian motion). But is there a case where let's say the bohmian wave function can create trajectories of particles that can control the macroscopic thermodynamics or has...

Why all liquids vaporize on boiling point instead of the temperature gradually increasing along with vapor pressure and more liquid atoms evaporating? Does it have anything to do with formation of vapor bubbles?

Homework Statement Homework EquationsThe Attempt at a Solution If I consider a specific case of adiabatic process , then ##dQ = 0 ## and ##dU = -PdV ## If we differentiate with respect to T on both sides , ##\frac{dU}{dT} = -P\frac{dV}{dT}## . Now , the closest I see is option B) , but...

Homework Statement I would very much like getting some help with my problem regarding the equations in some black hole thermodynamics. "Using the expression for the Schwarzschild radius, the entropy of a black hole of event-horizon area A=πR^2 can be written in terms of its mass using Eq. (1)...

Say you wanted to heat up your room. You could choose between an electric heater that outputs 500W or a PC that draws 500W. In both cases, the amount your room would heat up by would be the same, but the second case is much more advantageous because the computer can process information before...

Hello! There are so many Thermodynamics and Statistical Mechanics books that people suggest, that I don't know which one to use in my upcoming undergraduate course. So, which one is your favorite? Thanks in advance!

Hello, I have used Greiner's "Quantum Mechanics: An introduction" and found it to be awesome, bridging the ga between undergraduate and graduate courses. So, I am thinking of buying some of Greiner's book to use for my other courses and I wanted to ask you what your opinions about the books in...

Hello guys! I'm new here, so sorry if I'm posting on wrong place or wrong way. I just need help to solve a problem: (∂E/∂V)β, N + β(∂p/∂β)N, V = - p PS: There is a bar over E and over p (this in both sides) - meaning that is an average. I don't know how to start, so any help will be amazing...

Hi everyone Would like some help here. If I draw a control volume across a valve that I can control the flow area to, and I know the temperature and pressure upstream of the valve, I will know its enthalpy:in. High temperature liquid going through this valve supposedly changes to steam due...

Homework Statement Consider a rigid piston cylinder arrangement. Assume that the cylinder and the piston are covered by a perfectly insulating material and the piston cylinder interface is very smooth. Two types of ideal gases are separated in the cylinder by the piston. The number of gas...